<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <link:roleRef roleURI="http://www.nrgenergy.com/role/AccountingForDerivativeInstrumentsAndHedgingActivitiesAccountingForDerivativeInstrumentsAndHedgingActivitiesAociDetails" xlink:href="nrg-20180331.xsd#AccountingForDerivativeInstrumentsAndHedgingActivitiesAccountingForDerivativeInstrumentsAndHedgingActivitiesAociDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/AccountingForDerivativeInstrumentsAndHedgingActivitiesAccountingForDerivativeInstrumentsAndHedgingActivitiesFvOfDerivativesDetails" xlink:href="nrg-20180331.xsd#AccountingForDerivativeInstrumentsAndHedgingActivitiesAccountingForDerivativeInstrumentsAndHedgingActivitiesFvOfDerivativesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/AccountingForDerivativeInstrumentsAndHedgingActivitiesAccountingForDerivativeInstrumentsAndHedgingActivitiesImpactOnStatementOfOperationsDetails" xlink:href="nrg-20180331.xsd#AccountingForDerivativeInstrumentsAndHedgingActivitiesAccountingForDerivativeInstrumentsAndHedgingActivitiesImpactOnStatementOfOperationsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/AccountingForDerivativeInstrumentsAndHedgingActivitiesNotes" xlink:href="nrg-20180331.xsd#AccountingForDerivativeInstrumentsAndHedgingActivitiesNotes" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/AccountingForDerivativeInstrumentsAndHedgingActivitiesTables" xlink:href="nrg-20180331.xsd#AccountingForDerivativeInstrumentsAndHedgingActivitiesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/BusinessAcquisitions2018AcquisitionsDetails" xlink:href="nrg-20180331.xsd#BusinessAcquisitions2018AcquisitionsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/BusinessAcquisitionsBusinessAcquisitionsBuckthornSolarDropDownAssetDetails" xlink:href="nrg-20180331.xsd#BusinessAcquisitionsBusinessAcquisitionsBuckthornSolarDropDownAssetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/BusinessAcquisitionsBusinessAcquisitionsCvsrDetails" xlink:href="nrg-20180331.xsd#BusinessAcquisitionsBusinessAcquisitionsCvsrDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/BusinessAcquisitionsBusinessAcquisitionsMarch2017DropDowndetails" xlink:href="nrg-20180331.xsd#BusinessAcquisitionsBusinessAcquisitionsMarch2017DropDowndetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/BusinessAcquisitionsBusinessAcquisitionsNotes" xlink:href="nrg-20180331.xsd#BusinessAcquisitionsBusinessAcquisitionsNotes" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/BusinessAcquisitionsBusinessAcquisitionsNovember2017DropDownDetails" xlink:href="nrg-20180331.xsd#BusinessAcquisitionsBusinessAcquisitionsNovember2017DropDownDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/BusinessAcquisitionsBusinessAcquisitionsTables" xlink:href="nrg-20180331.xsd#BusinessAcquisitionsBusinessAcquisitionsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/BusinessAcquisitionsBusinessCombinationAugust2017DropDownDetails" xlink:href="nrg-20180331.xsd#BusinessAcquisitionsBusinessCombinationAugust2017DropDownDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/CommitmentsAndContingenciesDetails" xlink:href="nrg-20180331.xsd#CommitmentsAndContingenciesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/CommitmentsAndContingenciesNotes" xlink:href="nrg-20180331.xsd#CommitmentsAndContingenciesNotes" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/CommitmentsAndContingenciesTables" xlink:href="nrg-20180331.xsd#CommitmentsAndContingenciesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/CondensedConsolidatedStatementsOfOperations" xlink:href="nrg-20180331.xsd#CondensedConsolidatedStatementsOfOperations" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationCondensedConsolidatingFinancialInformation" xlink:href="nrg-20180331.xsd#CondensedConsolidatingFinancialInformationCondensedConsolidatingFinancialInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationCondensedConsolidatingFinancialInformationTables" xlink:href="nrg-20180331.xsd#CondensedConsolidatingFinancialInformationCondensedConsolidatingFinancialInformationTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationCpBalanceSheetDetails" xlink:href="nrg-20180331.xsd#CondensedConsolidatingFinancialInformationCpBalanceSheetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationCpCashFlowsDetails" xlink:href="nrg-20180331.xsd#CondensedConsolidatingFinancialInformationCpCashFlowsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationCpComprehensiveIncomeDetails" xlink:href="nrg-20180331.xsd#CondensedConsolidatingFinancialInformationCpComprehensiveIncomeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationCpIncomeStatementDetails" xlink:href="nrg-20180331.xsd#CondensedConsolidatingFinancialInformationCpIncomeStatementDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationPpBalanceSheetDetails" xlink:href="nrg-20180331.xsd#CondensedConsolidatingFinancialInformationPpBalanceSheetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationPpCashFlowsDetails" xlink:href="nrg-20180331.xsd#CondensedConsolidatingFinancialInformationPpCashFlowsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationPpComprehensiveIncomeDetails" xlink:href="nrg-20180331.xsd#CondensedConsolidatingFinancialInformationPpComprehensiveIncomeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationPpIncomeStatementDetails" xlink:href="nrg-20180331.xsd#CondensedConsolidatingFinancialInformationPpIncomeStatementDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/ConsolidatedBalanceSheets" xlink:href="nrg-20180331.xsd#ConsolidatedBalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/ConsolidatedStatementsOfCashFlows" xlink:href="nrg-20180331.xsd#ConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:href="nrg-20180331.xsd#ConsolidatedStatementsOfComprehensiveIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/DocumentAndEntityInformation" xlink:href="nrg-20180331.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/FairValueOfFinancialInstruments" xlink:href="nrg-20180331.xsd#FairValueOfFinancialInstruments" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/FairValueOfFinancialInstrumentsFairValueOfFinancialInstrumentsBalanceSheetGroupingDetails" xlink:href="nrg-20180331.xsd#FairValueOfFinancialInstrumentsFairValueOfFinancialInstrumentsBalanceSheetGroupingDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/FairValueOfFinancialInstrumentsFairValueOfFinancialInstrumentsCreditRiskAndDerivativeFvMeasurementsDetails" xlink:href="nrg-20180331.xsd#FairValueOfFinancialInstrumentsFairValueOfFinancialInstrumentsCreditRiskAndDerivativeFvMeasurementsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/FairValueOfFinancialInstrumentsFairValueOfFinancialInstrumentsRecurringFairValueDetails" xlink:href="nrg-20180331.xsd#FairValueOfFinancialInstrumentsFairValueOfFinancialInstrumentsRecurringFairValueDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/FairValueOfFinancialInstrumentsTables" xlink:href="nrg-20180331.xsd#FairValueOfFinancialInstrumentsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/LongTermDebt" xlink:href="nrg-20180331.xsd#LongTermDebt" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/LongTermDebtLongTermDebtDebtDisclosuresDetails" xlink:href="nrg-20180331.xsd#LongTermDebtLongTermDebtDebtDisclosuresDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/LongTermDebtLongTermDebtDebtTableDetails" xlink:href="nrg-20180331.xsd#LongTermDebtLongTermDebtDebtTableDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/LongTermDebtTables" xlink:href="nrg-20180331.xsd#LongTermDebtTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/NatureOfBusiness" xlink:href="nrg-20180331.xsd#NatureOfBusiness" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/NatureOfBusinessDetails" xlink:href="nrg-20180331.xsd#NatureOfBusinessDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/NatureOfBusinessNatureOfBusinessTables" xlink:href="nrg-20180331.xsd#NatureOfBusinessNatureOfBusinessTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/RelatedPartyTransactions" xlink:href="nrg-20180331.xsd#RelatedPartyTransactions" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/RelatedPartyTransactionsDetails" xlink:href="nrg-20180331.xsd#RelatedPartyTransactionsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/RelatedPartyTransactionsRelatedPartyTransactionsTables" xlink:href="nrg-20180331.xsd#RelatedPartyTransactionsRelatedPartyTransactionsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/SegmentReporting" xlink:href="nrg-20180331.xsd#SegmentReporting" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/SegmentReportingDetails" xlink:href="nrg-20180331.xsd#SegmentReportingDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/SegmentReportingSegmentReportingPolicies" xlink:href="nrg-20180331.xsd#SegmentReportingSegmentReportingPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/SegmentReportingTables" xlink:href="nrg-20180331.xsd#SegmentReportingTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/SummaryOfSignificantAccountingPolicies" xlink:href="nrg-20180331.xsd#SummaryOfSignificantAccountingPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/SummaryOfSignificantAccountingPoliciesDetails" xlink:href="nrg-20180331.xsd#SummaryOfSignificantAccountingPoliciesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/SummaryOfSignificantAccountingPoliciesSummaryOfSignificantAccountingPoliciesPolicies" xlink:href="nrg-20180331.xsd#SummaryOfSignificantAccountingPoliciesSummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/SummaryOfSignificantAccountingPoliciesSummaryOfSignificantAccountingPoliciesTables" xlink:href="nrg-20180331.xsd#SummaryOfSignificantAccountingPoliciesSummaryOfSignificantAccountingPoliciesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/VariableInterestEntities" xlink:href="nrg-20180331.xsd#VariableInterestEntities" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/VariableInterestEntitiesTables" xlink:href="nrg-20180331.xsd#VariableInterestEntitiesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/VariableInterestEntitiesVariableInterestEntitiesConsolidatedEntitiesDetails" xlink:href="nrg-20180331.xsd#VariableInterestEntitiesVariableInterestEntitiesConsolidatedEntitiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/VariableInterestEntitiesVariableInterestEntitiesDebtHeldByUnconsolidatedAffiliatesDetails" xlink:href="nrg-20180331.xsd#VariableInterestEntitiesVariableInterestEntitiesDebtHeldByUnconsolidatedAffiliatesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/VariableInterestEntitiesVariableInterestEntitiesUnconsolidatedEntitiesDetails" xlink:href="nrg-20180331.xsd#VariableInterestEntitiesVariableInterestEntitiesUnconsolidatedEntitiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nrgenergy.com/role/VariableInterestEntitiesVariableInterestEntitiesUtahSolarPortfolioDetails" xlink:href="nrg-20180331.xsd#VariableInterestEntitiesVariableInterestEntitiesUtahSolarPortfolioDetails" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/AccountingForDerivativeInstrumentsAndHedgingActivitiesAccountingForDerivativeInstrumentsAndHedgingActivitiesAociDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_E197BC0B63467FBDB022FD65C4D95E02" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_C20EB955DB73BA409634FD65C4D99912" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_E197BC0B63467FBDB022FD65C4D95E02" xlink:to="loc_us-gaap_DerivativeTable_C20EB955DB73BA409634FD65C4D99912" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_A51A3B70EEDA8A6B5F49FD65C4D91D09" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_C20EB955DB73BA409634FD65C4D99912" xlink:to="loc_us-gaap_StatementScenarioAxis_A51A3B70EEDA8A6B5F49FD65C4D91D09" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_C104087CECF96AEC8A3AFD65C4D9AD85_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_A51A3B70EEDA8A6B5F49FD65C4D91D09" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_C104087CECF96AEC8A3AFD65C4D9AD85_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_C104087CECF96AEC8A3AFD65C4D9AD85" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_A51A3B70EEDA8A6B5F49FD65C4D91D09" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_C104087CECF96AEC8A3AFD65C4D9AD85" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SuccessorMember" xlink:label="loc_us-gaap_SuccessorMember_435CFC7305B7EB83797CFD65C4D9325C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScenarioUnspecifiedDomain_C104087CECF96AEC8A3AFD65C4D9AD85" xlink:to="loc_us-gaap_SuccessorMember_435CFC7305B7EB83797CFD65C4D9325C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_AAABCF1BC99143D1AB24FD65C4D9F225" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_C20EB955DB73BA409634FD65C4D99912" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_AAABCF1BC99143D1AB24FD65C4D9F225" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_DA3AEE5802480ADCEECAFD65C4D92D0F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_AAABCF1BC99143D1AB24FD65C4D9F225" xlink:to="loc_us-gaap_EquityComponentDomain_DA3AEE5802480ADCEECAFD65C4D92D0F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_DA3AEE5802480ADCEECAFD65C4D92D0F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_AAABCF1BC99143D1AB24FD65C4D9F225" xlink:to="loc_us-gaap_EquityComponentDomain_DA3AEE5802480ADCEECAFD65C4D92D0F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="loc_us-gaap_NoncontrollingInterestMember_EA719E8ED65BC0340AAFFD65C4D9E146" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_DA3AEE5802480ADCEECAFD65C4D92D0F" xlink:to="loc_us-gaap_NoncontrollingInterestMember_EA719E8ED65BC0340AAFFD65C4D9E146" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax_2382D9EE7AD96D242BD4FD65C4D97BE3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_E197BC0B63467FBDB022FD65C4D95E02" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax_2382D9EE7AD96D242BD4FD65C4D97BE3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet_D256BE02E441857828C5FD65C4D9F3F4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_E197BC0B63467FBDB022FD65C4D95E02" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet_D256BE02E441857828C5FD65C4D9F3F4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax_73960EEB90B35000C2F7FD65C4D94663" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_E197BC0B63467FBDB022FD65C4D95E02" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax_73960EEB90B35000C2F7FD65C4D94663" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths" xlink:label="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_46034A02FBC9CC9F818CFD65C4D9C868" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_E197BC0B63467FBDB022FD65C4D95E02" xlink:to="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_46034A02FBC9CC9F818CFD65C4D9C868" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GainLossOnCashFlowHedgeIneffectivenessNet" xlink:label="loc_us-gaap_GainLossOnCashFlowHedgeIneffectivenessNet_C8B96F7FA97444D936C2FD65C4D904AF" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_E197BC0B63467FBDB022FD65C4D95E02" xlink:to="loc_us-gaap_GainLossOnCashFlowHedgeIneffectivenessNet_C8B96F7FA97444D936C2FD65C4D904AF" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/AccountingForDerivativeInstrumentsAndHedgingActivitiesAccountingForDerivativeInstrumentsAndHedgingActivitiesFvOfDerivativesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativesFairValueLineItems" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_C2F1019DF5E4F26FF7D9FD65C4E042CB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_C2F1019DF5E4F26FF7D9FD65C4E042CB" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_EB768E564801F2F9330BFD65C4E0D135" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_C2F1019DF5E4F26FF7D9FD65C4E042CB" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_EB768E564801F2F9330BFD65C4E0D135" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_2EA2094C9FF2DA1C0C41FD65C4E08DF0_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_EB768E564801F2F9330BFD65C4E0D135" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_2EA2094C9FF2DA1C0C41FD65C4E08DF0_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_2EA2094C9FF2DA1C0C41FD65C4E08DF0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_EB768E564801F2F9330BFD65C4E0D135" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_2EA2094C9FF2DA1C0C41FD65C4E08DF0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestExpenseMember" xlink:label="loc_us-gaap_InterestExpenseMember_7270FFBB2D5A853A557FFD65C4E0E0EA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_2EA2094C9FF2DA1C0C41FD65C4E08DF0" xlink:to="loc_us-gaap_InterestExpenseMember_7270FFBB2D5A853A557FFD65C4E0E0EA" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_MeasurementUnitAxis" xlink:label="loc_nrg_MeasurementUnitAxis_3984B7ACDEEF8DE642BDFD65C4E01D81" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_C2F1019DF5E4F26FF7D9FD65C4E042CB" xlink:to="loc_nrg_MeasurementUnitAxis_3984B7ACDEEF8DE642BDFD65C4E01D81" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_MeasurementUnitDomain" xlink:label="loc_nrg_MeasurementUnitDomain_54683DF4E97CB312E472FD65C4E0C963_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_nrg_MeasurementUnitAxis_3984B7ACDEEF8DE642BDFD65C4E01D81" xlink:to="loc_nrg_MeasurementUnitDomain_54683DF4E97CB312E472FD65C4E0C963_default" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_MeasurementUnitDomain" xlink:label="loc_nrg_MeasurementUnitDomain_54683DF4E97CB312E472FD65C4E0C963" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_nrg_MeasurementUnitAxis_3984B7ACDEEF8DE642BDFD65C4E01D81" xlink:to="loc_nrg_MeasurementUnitDomain_54683DF4E97CB312E472FD65C4E0C963" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/currency/2017/currency-2017-01-31.xsd#currency_USD" xlink:label="loc_currency_USD_F6EFCE95CFE032B63B07FD65C4E05ED2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_MeasurementUnitDomain_54683DF4E97CB312E472FD65C4E0C963" xlink:to="loc_currency_USD_F6EFCE95CFE032B63B07FD65C4E05ED2" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_MmbtuMember" xlink:label="loc_nrg_MmbtuMember_BE69F68D9C87EE121A85FD65C4E0CC1F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_MeasurementUnitDomain_54683DF4E97CB312E472FD65C4E0C963" xlink:to="loc_nrg_MmbtuMember_BE69F68D9C87EE121A85FD65C4E0CC1F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnderlyingAssetClassAxis" xlink:label="loc_us-gaap_UnderlyingAssetClassAxis_33FBB362441707186E50FD65C4E053A0" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_C2F1019DF5E4F26FF7D9FD65C4E042CB" xlink:to="loc_us-gaap_UnderlyingAssetClassAxis_33FBB362441707186E50FD65C4E053A0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnderlyingAssetClassDomain" xlink:label="loc_us-gaap_UnderlyingAssetClassDomain_44C48658547DDB6239E6FD65C4E091AD_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_UnderlyingAssetClassAxis_33FBB362441707186E50FD65C4E053A0" xlink:to="loc_us-gaap_UnderlyingAssetClassDomain_44C48658547DDB6239E6FD65C4E091AD_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnderlyingAssetClassDomain" xlink:label="loc_us-gaap_UnderlyingAssetClassDomain_44C48658547DDB6239E6FD65C4E091AD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_UnderlyingAssetClassAxis_33FBB362441707186E50FD65C4E053A0" xlink:to="loc_us-gaap_UnderlyingAssetClassDomain_44C48658547DDB6239E6FD65C4E091AD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NaturalGasReservesMember" xlink:label="loc_us-gaap_NaturalGasReservesMember_CB1A16ED097B28393FEFFD65C4E0B547" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnderlyingAssetClassDomain_44C48658547DDB6239E6FD65C4E091AD" xlink:to="loc_us-gaap_NaturalGasReservesMember_CB1A16ED097B28393FEFFD65C4E0B547" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_InterestMember" xlink:label="loc_nrg_InterestMember_433D41C2D381E3C88B1BFD65C4E0B788" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnderlyingAssetClassDomain_44C48658547DDB6239E6FD65C4E091AD" xlink:to="loc_nrg_InterestMember_433D41C2D381E3C88B1BFD65C4E0B788" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_BA40FAA6753A9532B877FD65C4E07BD2" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_C2F1019DF5E4F26FF7D9FD65C4E042CB" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_BA40FAA6753A9532B877FD65C4E07BD2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_4EB09ABD509D73C3A467FD65C4E022DF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_BA40FAA6753A9532B877FD65C4E07BD2" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_4EB09ABD509D73C3A467FD65C4E022DF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_4EB09ABD509D73C3A467FD65C4E022DF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_BA40FAA6753A9532B877FD65C4E07BD2" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_4EB09ABD509D73C3A467FD65C4E022DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommodityContractMember" xlink:label="loc_us-gaap_CommodityContractMember_281CBC93603E59D638EEFD65C4E05E0C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_4EB09ABD509D73C3A467FD65C4E022DF" xlink:to="loc_us-gaap_CommodityContractMember_281CBC93603E59D638EEFD65C4E05E0C" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_InterestRateContractCurrentMember" xlink:label="loc_nrg_InterestRateContractCurrentMember_A9CAE18EF6AF81A8600FFD65C4E1756E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_4EB09ABD509D73C3A467FD65C4E022DF" xlink:to="loc_nrg_InterestRateContractCurrentMember_A9CAE18EF6AF81A8600FFD65C4E1756E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_InterestRateContractNonCurrentMember" xlink:label="loc_nrg_InterestRateContractNonCurrentMember_01B9BB4A211CEBB576CDFD65C4E159D1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_4EB09ABD509D73C3A467FD65C4E022DF" xlink:to="loc_nrg_InterestRateContractNonCurrentMember_01B9BB4A211CEBB576CDFD65C4E159D1" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CommodityContractCurrentMember" xlink:label="loc_nrg_CommodityContractCurrentMember_0AFF06D49CE70996CB8DFD65C4E18B95" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_4EB09ABD509D73C3A467FD65C4E022DF" xlink:to="loc_nrg_CommodityContractCurrentMember_0AFF06D49CE70996CB8DFD65C4E18B95" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestRateContractMember" xlink:label="loc_us-gaap_InterestRateContractMember_9C30A00959B1992C7C86FD65C4E191D0" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_4EB09ABD509D73C3A467FD65C4E022DF" xlink:to="loc_us-gaap_InterestRateContractMember_9C30A00959B1992C7C86FD65C4E191D0" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CommodityContractNonCurrentMember" xlink:label="loc_nrg_CommodityContractNonCurrentMember_50053E3FEBE7A1FEE340FD65C4E147DB" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_4EB09ABD509D73C3A467FD65C4E022DF" xlink:to="loc_nrg_CommodityContractNonCurrentMember_50053E3FEBE7A1FEE340FD65C4E147DB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_4BEAD9A574802F9D0C50FD65C4E1AD39" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_C2F1019DF5E4F26FF7D9FD65C4E042CB" xlink:to="loc_us-gaap_HedgingDesignationAxis_4BEAD9A574802F9D0C50FD65C4E1AD39" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_98B1826BF5910AC600F2FD65C4E1FDFE_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_4BEAD9A574802F9D0C50FD65C4E1AD39" xlink:to="loc_us-gaap_HedgingDesignationDomain_98B1826BF5910AC600F2FD65C4E1FDFE_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_98B1826BF5910AC600F2FD65C4E1FDFE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_4BEAD9A574802F9D0C50FD65C4E1AD39" xlink:to="loc_us-gaap_HedgingDesignationDomain_98B1826BF5910AC600F2FD65C4E1FDFE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_39D828DFC6CFE674417EFD65C4E12A7D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_98B1826BF5910AC600F2FD65C4E1FDFE" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_39D828DFC6CFE674417EFD65C4E12A7D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NondesignatedMember" xlink:label="loc_us-gaap_NondesignatedMember_F4D7ADF3E3D9DC3810B4FD65C4E1878F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_98B1826BF5910AC600F2FD65C4E1FDFE" xlink:to="loc_us-gaap_NondesignatedMember_F4D7ADF3E3D9DC3810B4FD65C4E1878F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_C39CBC2FDC0060976291FD65C4E10552" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_C39CBC2FDC0060976291FD65C4E10552" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_DerivativeNotionalAmount" xlink:label="loc_invest_DerivativeNotionalAmount_7647DC2C54F7F0FC25C8FD65C4E1F9A1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:to="loc_invest_DerivativeNotionalAmount_7647DC2C54F7F0FC25C8FD65C4E1F9A1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_18F98CC93EBC5A1D8C47FD65C4E1290B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_18F98CC93EBC5A1D8C47FD65C4E1290B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeCollateralRightToReclaimCash" xlink:label="loc_us-gaap_DerivativeCollateralRightToReclaimCash_F590E8D34B93B66796FEFD65C4E141FF" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:to="loc_us-gaap_DerivativeCollateralRightToReclaimCash_F590E8D34B93B66796FEFD65C4E141FF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeCollateralObligationToReturnCash" xlink:label="loc_us-gaap_DerivativeCollateralObligationToReturnCash_2B805BBD086B2830B94DFD65C4E13DDE" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:to="loc_us-gaap_DerivativeCollateralObligationToReturnCash_2B805BBD086B2830B94DFD65C4E13DDE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeAssetFairValueGrossLiability" xlink:label="loc_us-gaap_DerivativeAssetFairValueGrossLiability_62A86AC290B41B3EC956FD65C4E2EB94" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:to="loc_us-gaap_DerivativeAssetFairValueGrossLiability_62A86AC290B41B3EC956FD65C4E2EB94" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeAssets" xlink:label="loc_us-gaap_DerivativeAssets_EA4DEF6B0261A76C00F7FD65C4E25954" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:to="loc_us-gaap_DerivativeAssets_EA4DEF6B0261A76C00F7FD65C4E25954" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilityFairValueGrossAsset" xlink:label="loc_us-gaap_DerivativeLiabilityFairValueGrossAsset_4F1A59A1B3438555161AFD65C4E28573" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:to="loc_us-gaap_DerivativeLiabilityFairValueGrossAsset_4F1A59A1B3438555161AFD65C4E28573" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilities" xlink:label="loc_us-gaap_DerivativeLiabilities_9EC45421AF58FE09026AFD65C4E21BE9" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:to="loc_us-gaap_DerivativeLiabilities_9EC45421AF58FE09026AFD65C4E21BE9" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_FairValueofGrossDerivativeAssetsLiabilitiesNet" xlink:label="loc_nrg_FairValueofGrossDerivativeAssetsLiabilitiesNet_BB99C04DF794DF81C786FD65C4E26297" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:to="loc_nrg_FairValueofGrossDerivativeAssetsLiabilitiesNet_BB99C04DF794DF81C786FD65C4E26297" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_DerivativeAssetFairValueGrossLiabilityNetOfDerivativeLiabilityFairValueGrossAsset" xlink:label="loc_nrg_DerivativeAssetFairValueGrossLiabilityNetOfDerivativeLiabilityFairValueGrossAsset_AE20CDEBB450A497846CFD65C4E2A0BF" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:to="loc_nrg_DerivativeAssetFairValueGrossLiabilityNetOfDerivativeLiabilityFairValueGrossAsset_AE20CDEBB450A497846CFD65C4E2A0BF" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_DerivativeAssetFairValueAmountOffsetAgainstCollateralNetOfDerivativeLiabilityFairValueAmountOffsetAgainstCollateral" xlink:label="loc_nrg_DerivativeAssetFairValueAmountOffsetAgainstCollateralNetOfDerivativeLiabilityFairValueAmountOffsetAgainstCollateral_AB55691671983CB60FC4FD65C4E23329" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:to="loc_nrg_DerivativeAssetFairValueAmountOffsetAgainstCollateralNetOfDerivativeLiabilityFairValueAmountOffsetAgainstCollateral_AB55691671983CB60FC4FD65C4E23329" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnrealizedGainLossOnDerivatives" xlink:label="loc_us-gaap_UnrealizedGainLossOnDerivatives_038F50A2DA36A6657DC6FD65C4E27067" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_24A17B35ACBBBFB33EC4FD65C4E141BF" xlink:to="loc_us-gaap_UnrealizedGainLossOnDerivatives_038F50A2DA36A6657DC6FD65C4E27067" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/AccountingForDerivativeInstrumentsAndHedgingActivitiesAccountingForDerivativeInstrumentsAndHedgingActivitiesImpactOnStatementOfOperationsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_5E38BA04B850371CC36C1769DF047E69" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_D9EC0BDFDCB0B77C826F1769DF0264E7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_5E38BA04B850371CC36C1769DF047E69" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_D9EC0BDFDCB0B77C826F1769DF0264E7" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_546D0025F239EA5B65CF1769DF030EFC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_D9EC0BDFDCB0B77C826F1769DF0264E7" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_546D0025F239EA5B65CF1769DF030EFC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_08688B835F5F127189571769DF03F553_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_546D0025F239EA5B65CF1769DF030EFC" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_08688B835F5F127189571769DF03F553_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_08688B835F5F127189571769DF03F553" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_546D0025F239EA5B65CF1769DF030EFC" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_08688B835F5F127189571769DF03F553" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestRateContractMember" xlink:label="loc_us-gaap_InterestRateContractMember_BE28283F0F4BF64A10EA1769DF039136" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_08688B835F5F127189571769DF03F553" xlink:to="loc_us-gaap_InterestRateContractMember_BE28283F0F4BF64A10EA1769DF039136" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_93E0BDB5550D2C105E861769DF036D30" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_D9EC0BDFDCB0B77C826F1769DF0264E7" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_93E0BDB5550D2C105E861769DF036D30" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_E876BE0D1666C63DB5861769DF03D042_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_93E0BDB5550D2C105E861769DF036D30" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_E876BE0D1666C63DB5861769DF03D042_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_E876BE0D1666C63DB5861769DF03D042" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_93E0BDB5550D2C105E861769DF036D30" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_E876BE0D1666C63DB5861769DF03D042" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestExpenseMember" xlink:label="loc_us-gaap_InterestExpenseMember_629D6DFF71E62376D6381769DF03C2F4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_E876BE0D1666C63DB5861769DF03D042" xlink:to="loc_us-gaap_InterestExpenseMember_629D6DFF71E62376D6381769DF03C2F4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnrealizedGainLossOnDerivatives" xlink:label="loc_us-gaap_UnrealizedGainLossOnDerivatives_3C8B020705E75CF436041769DF044501" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_5E38BA04B850371CC36C1769DF047E69" xlink:to="loc_us-gaap_UnrealizedGainLossOnDerivatives_3C8B020705E75CF436041769DF044501" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/AccountingForDerivativeInstrumentsAndHedgingActivitiesNotes" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/AccountingForDerivativeInstrumentsAndHedgingActivitiesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/BusinessAcquisitions2018AcquisitionsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:label="loc_us-gaap_SubsequentEventLineItems_8C10D06C148C291713C70741D79A31CE" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTable" xlink:label="loc_us-gaap_SubsequentEventTable_707028F673D6D8D9097E0741D7991C1C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_8C10D06C148C291713C70741D79A31CE" xlink:to="loc_us-gaap_SubsequentEventTable_707028F673D6D8D9097E0741D7991C1C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_1EE4DB764C22E35632CA0741D7997115" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_707028F673D6D8D9097E0741D7991C1C" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_1EE4DB764C22E35632CA0741D7997115" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C9FEED5C304E69B34D4E0741D79AD229_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_1EE4DB764C22E35632CA0741D7997115" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C9FEED5C304E69B34D4E0741D79AD229_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C9FEED5C304E69B34D4E0741D79AD229" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_1EE4DB764C22E35632CA0741D7997115" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C9FEED5C304E69B34D4E0741D79AD229" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CentralCAFuelCell1Member" xlink:label="loc_nrg_CentralCAFuelCell1Member_D2490FCDE7A0D2BD375D0741D79A108E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C9FEED5C304E69B34D4E0741D79AD229" xlink:to="loc_nrg_CentralCAFuelCell1Member_D2490FCDE7A0D2BD375D0741D79A108E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_17F6961633424D3CA3400741D79A4635" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_707028F673D6D8D9097E0741D7991C1C" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_17F6961633424D3CA3400741D79A4635" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_93796E0BA70695274F9A0741D79AB32D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_17F6961633424D3CA3400741D79A4635" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_93796E0BA70695274F9A0741D79AB32D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_93796E0BA70695274F9A0741D79AB32D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_17F6961633424D3CA3400741D79A4635" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_93796E0BA70695274F9A0741D79AB32D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_759DB915F945737F82BD0741D79A8FC7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_93796E0BA70695274F9A0741D79AB32D" xlink:to="loc_us-gaap_SubsequentEventMember_759DB915F945737F82BD0741D79A8FC7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_F3257ADCDFD4997D11460741D79A3B0E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_8C10D06C148C291713C70741D79A31CE" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_F3257ADCDFD4997D11460741D79A3B0E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationCapacityMegawatts" xlink:label="loc_nrg_PowerGenerationCapacityMegawatts_23447462460A81D02C310741D79B5C4D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_8C10D06C148C291713C70741D79A31CE" xlink:to="loc_nrg_PowerGenerationCapacityMegawatts_23447462460A81D02C310741D79B5C4D" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerPurchaseAgreementPeriod" xlink:label="loc_nrg_PowerPurchaseAgreementPeriod_FCEB3E57AFC375046AE20741D79B1085" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_8C10D06C148C291713C70741D79A31CE" xlink:to="loc_nrg_PowerPurchaseAgreementPeriod_FCEB3E57AFC375046AE20741D79B1085" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/BusinessAcquisitionsBusinessAcquisitionsBuckthornSolarDropDownAssetDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_172C935F9B8CB0D0C6290741D7A18F77" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_172C935F9B8CB0D0C6290741D7A18F77" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_E036E07B309361133CB40741D7A1405A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_172C935F9B8CB0D0C6290741D7A18F77" xlink:to="loc_us-gaap_DebtInstrumentAxis_E036E07B309361133CB40741D7A1405A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_315364087D6797F26CDA0741D7A11FAA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_E036E07B309361133CB40741D7A1405A" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_315364087D6797F26CDA0741D7A11FAA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_315364087D6797F26CDA0741D7A11FAA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_E036E07B309361133CB40741D7A1405A" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_315364087D6797F26CDA0741D7A11FAA" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BuckthornSolarDropDownAssetMember" xlink:label="loc_nrg_BuckthornSolarDropDownAssetMember_52F6223E531BB2BEA5210741D7A1BDA5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_315364087D6797F26CDA0741D7A11FAA" xlink:to="loc_nrg_BuckthornSolarDropDownAssetMember_52F6223E531BB2BEA5210741D7A1BDA5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_78B55D9DFF043D9D28A90741D7A1F77E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_172C935F9B8CB0D0C6290741D7A18F77" xlink:to="loc_us-gaap_StatementScenarioAxis_78B55D9DFF043D9D28A90741D7A1F77E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_9087C2327155281ADC480741D7A15622_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_78B55D9DFF043D9D28A90741D7A1F77E" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_9087C2327155281ADC480741D7A15622_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_9087C2327155281ADC480741D7A15622" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_78B55D9DFF043D9D28A90741D7A1F77E" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_9087C2327155281ADC480741D7A15622" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioPreviouslyReportedMember" xlink:label="loc_us-gaap_ScenarioPreviouslyReportedMember_9A588AE130C30579D8AB0741D7A14479" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScenarioUnspecifiedDomain_9087C2327155281ADC480741D7A15622" xlink:to="loc_us-gaap_ScenarioPreviouslyReportedMember_9A588AE130C30579D8AB0741D7A14479" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_1FDB29E5CB16194E13820741D7A2AA1A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_172C935F9B8CB0D0C6290741D7A18F77" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_1FDB29E5CB16194E13820741D7A2AA1A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_FD98B1E767E7D345A2D20741D7A20411_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_1FDB29E5CB16194E13820741D7A2AA1A" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_FD98B1E767E7D345A2D20741D7A20411_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_FD98B1E767E7D345A2D20741D7A20411" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_1FDB29E5CB16194E13820741D7A2AA1A" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_FD98B1E767E7D345A2D20741D7A20411" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BuckthornSolarDropDownAssetMember" xlink:label="loc_nrg_BuckthornSolarDropDownAssetMember_284A4911B1D6E2D9E72D0741D7A22283" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_FD98B1E767E7D345A2D20741D7A20411" xlink:to="loc_nrg_BuckthornSolarDropDownAssetMember_284A4911B1D6E2D9E72D0741D7A22283" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_C407239E23C4892FCBE90741D7A29349" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_172C935F9B8CB0D0C6290741D7A18F77" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_C407239E23C4892FCBE90741D7A29349" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_EC1312D686ED660295230741D7A2E6E4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_C407239E23C4892FCBE90741D7A29349" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_EC1312D686ED660295230741D7A2E6E4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_EC1312D686ED660295230741D7A2E6E4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_C407239E23C4892FCBE90741D7A29349" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_EC1312D686ED660295230741D7A2E6E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipAxis" xlink:label="loc_us-gaap_OwnershipAxis_61EC9646E5ADA64D85580741D7A2A2F7" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_172C935F9B8CB0D0C6290741D7A18F77" xlink:to="loc_us-gaap_OwnershipAxis_61EC9646E5ADA64D85580741D7A2A2F7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipDomain" xlink:label="loc_us-gaap_OwnershipDomain_1AD0939F396D170D05920741D7A2E57D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OwnershipAxis_61EC9646E5ADA64D85580741D7A2A2F7" xlink:to="loc_us-gaap_OwnershipDomain_1AD0939F396D170D05920741D7A2E57D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipDomain" xlink:label="loc_us-gaap_OwnershipDomain_1AD0939F396D170D05920741D7A2E57D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OwnershipAxis_61EC9646E5ADA64D85580741D7A2A2F7" xlink:to="loc_us-gaap_OwnershipDomain_1AD0939F396D170D05920741D7A2E57D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_A219BC9156634806F7610741D7A2A9BA" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_172C935F9B8CB0D0C6290741D7A18F77" xlink:to="loc_us-gaap_StatementClassOfStockAxis_A219BC9156634806F7610741D7A2A9BA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_7B286C88BD9B5A13CAA70741D7A2D4CB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_A219BC9156634806F7610741D7A2A9BA" xlink:to="loc_us-gaap_ClassOfStockDomain_7B286C88BD9B5A13CAA70741D7A2D4CB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_7B286C88BD9B5A13CAA70741D7A2D4CB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_A219BC9156634806F7610741D7A2A9BA" xlink:to="loc_us-gaap_ClassOfStockDomain_7B286C88BD9B5A13CAA70741D7A2D4CB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_FF5D2A46DB47A76B2B750741D7A31D4C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_FF5D2A46DB47A76B2B750741D7A31D4C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_FBEDFB0CB07832E2A4F40741D7A3AA77" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_FBEDFB0CB07832E2A4F40741D7A3AA77" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_2CB7C860CEB5E08BB09F0741D7A331DC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_2CB7C860CEB5E08BB09F0741D7A331DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_4817FE12E4903D6886C10741D7A31DFE" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_LongTermDebt_4817FE12E4903D6886C10741D7A31DFE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue_670A57E44C835865A5F6076A49482D58" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue_670A57E44C835865A5F6076A49482D58" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationCapacityMegawatts" xlink:label="loc_nrg_PowerGenerationCapacityMegawatts_4C71BB03C16AB40CA1C90741D7A3B58D" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_nrg_PowerGenerationCapacityMegawatts_4C71BB03C16AB40CA1C90741D7A3B58D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_F8696A13AB4B9749F8C40741D7A31965" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_F8696A13AB4B9749F8C40741D7A31965" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_56B71E69B2CA23D4D4300741D7A3FFC9" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_AssetsCurrent_56B71E69B2CA23D4D4300741D7A3FFC9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_D433C05A6C3327EEECA50741D7A3A3FB" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_D433C05A6C3327EEECA50741D7A3A3FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssets" xlink:label="loc_us-gaap_OtherAssets_ACD996E614C13B4DABFE0741D7A3A914" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_OtherAssets_ACD996E614C13B4DABFE0741D7A3A914" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_9C2DEB235A904C823A140741D7A36DF2" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_Assets_9C2DEB235A904C823A140741D7A36DF2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtLongtermAndShorttermCombinedAmount" xlink:label="loc_us-gaap_DebtLongtermAndShorttermCombinedAmount_37D4F796F13806DC722F0741D7A48659" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_DebtLongtermAndShorttermCombinedAmount_37D4F796F13806DC722F0741D7A48659" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilities" xlink:label="loc_us-gaap_OtherLiabilities_05BFFB21CD0F72E59D5D0741D7A45F1A" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_OtherLiabilities_05BFFB21CD0F72E59D5D0741D7A45F1A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_5F96CD06D1FB238BC5D80741D7A4FEAB" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_Liabilities_5F96CD06D1FB238BC5D80741D7A4FEAB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_20D0F7C798ED2BF227A40741D7A45AE0" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_20D0F7C798ED2BF227A40741D7A45AE0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MembersEquity" xlink:label="loc_us-gaap_MembersEquity_2E5BBBFD7B6C705342A50741D7A41CB9" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_MembersEquity_2E5BBBFD7B6C705342A50741D7A41CB9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_E78FAC430A0285FD221A0741D7A41638" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_E78FAC430A0285FD221A0741D7A41638" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_3334BA44912AC9B9E0930741D7A4EB0F" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_3334BA44912AC9B9E0930741D7A4EB0F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancialLiabilities" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancialLiabilities_7D36F45A8DC055B53E7C0741D7A4B61D" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancialLiabilities_7D36F45A8DC055B53E7C0741D7A4B61D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_03EA6B2FEBB56A914CA20741D7A40472" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_03EA6B2FEBB56A914CA20741D7A40472" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_0E2B2F53F507B95AF81F0741D7A4E052" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_0E2B2F53F507B95AF81F0741D7A4E052" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BusinessAcquisitionConsiderationTransferredWorkingCapital" xlink:label="loc_nrg_BusinessAcquisitionConsiderationTransferredWorkingCapital_86A50C96C19CF8F55957076A4E5B098E" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_EE8389E205BBD047DAF00741D7A2D04F" xlink:to="loc_nrg_BusinessAcquisitionConsiderationTransferredWorkingCapital_86A50C96C19CF8F55957076A4E5B098E" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/BusinessAcquisitionsBusinessAcquisitionsCvsrDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_E8D19BA53BFAC1B4CA741C5E596BC6F1" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0B8DB9A33BA886785B8E1C5E59683DAD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E8D19BA53BFAC1B4CA741C5E596BC6F1" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0B8DB9A33BA886785B8E1C5E59683DAD" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_59C1014F3AE64D7E83121C5E59697E42" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0B8DB9A33BA886785B8E1C5E59683DAD" xlink:to="loc_us-gaap_DebtInstrumentAxis_59C1014F3AE64D7E83121C5E59697E42" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_1E38B50ED0F88A2FC33D1C5E59693C47_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_59C1014F3AE64D7E83121C5E59697E42" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_1E38B50ED0F88A2FC33D1C5E59693C47_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_1E38B50ED0F88A2FC33D1C5E59693C47" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_59C1014F3AE64D7E83121C5E59697E42" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_1E38B50ED0F88A2FC33D1C5E59693C47" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CvsrFinancingAgreementMember" xlink:label="loc_nrg_CvsrFinancingAgreementMember_DA5054FD3A9903B5DBF41C5E5969EE39" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1E38B50ED0F88A2FC33D1C5E59693C47" xlink:to="loc_nrg_CvsrFinancingAgreementMember_DA5054FD3A9903B5DBF41C5E5969EE39" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CVSRHoldcodue2037Member" xlink:label="loc_nrg_CVSRHoldcodue2037Member_072ABA0B3995E5A9E77B1C5E5969F54F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1E38B50ED0F88A2FC33D1C5E59693C47" xlink:to="loc_nrg_CVSRHoldcodue2037Member_072ABA0B3995E5A9E77B1C5E5969F54F" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationFacilitiesByTypeAxis" xlink:label="loc_nrg_PowerGenerationFacilitiesByTypeAxis_617CDBBA4A4D280B01F51C5E5969D624" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0B8DB9A33BA886785B8E1C5E59683DAD" xlink:to="loc_nrg_PowerGenerationFacilitiesByTypeAxis_617CDBBA4A4D280B01F51C5E5969D624" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationFacilitiesTypeDomain" xlink:label="loc_nrg_PowerGenerationFacilitiesTypeDomain_5461CA88D9081AB6C3601C5E5969444A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_nrg_PowerGenerationFacilitiesByTypeAxis_617CDBBA4A4D280B01F51C5E5969D624" xlink:to="loc_nrg_PowerGenerationFacilitiesTypeDomain_5461CA88D9081AB6C3601C5E5969444A_default" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationFacilitiesTypeDomain" xlink:label="loc_nrg_PowerGenerationFacilitiesTypeDomain_5461CA88D9081AB6C3601C5E5969444A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_nrg_PowerGenerationFacilitiesByTypeAxis_617CDBBA4A4D280B01F51C5E5969D624" xlink:to="loc_nrg_PowerGenerationFacilitiesTypeDomain_5461CA88D9081AB6C3601C5E5969444A" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_UtilityScaleSolarMember" xlink:label="loc_nrg_UtilityScaleSolarMember_3C596AEA3673912A6CED1C5E59691612" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_PowerGenerationFacilitiesTypeDomain_5461CA88D9081AB6C3601C5E5969444A" xlink:to="loc_nrg_UtilityScaleSolarMember_3C596AEA3673912A6CED1C5E59691612" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_1DDD874FEB4154DA93461C5E59695B27" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0B8DB9A33BA886785B8E1C5E59683DAD" xlink:to="loc_dei_LegalEntityAxis_1DDD874FEB4154DA93461C5E59695B27" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_4C826387F118246D1A251C5E596AA11A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_1DDD874FEB4154DA93461C5E59695B27" xlink:to="loc_dei_EntityDomain_4C826387F118246D1A251C5E596AA11A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_4C826387F118246D1A251C5E596AA11A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_1DDD874FEB4154DA93461C5E59695B27" xlink:to="loc_dei_EntityDomain_4C826387F118246D1A251C5E596AA11A" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CvsrMember" xlink:label="loc_nrg_CvsrMember_A268218C90AFBEA35CA11C5E596A5A87" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_4C826387F118246D1A251C5E596AA11A" xlink:to="loc_nrg_CvsrMember_A268218C90AFBEA35CA11C5E596A5A87" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_889F9549BF6E53A437541C5E596A8BD3" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0B8DB9A33BA886785B8E1C5E59683DAD" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_889F9549BF6E53A437541C5E596A8BD3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_6DCEE74753B831174E921C5E596ABA98_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_889F9549BF6E53A437541C5E596A8BD3" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_6DCEE74753B831174E921C5E596ABA98_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_6DCEE74753B831174E921C5E596ABA98" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_889F9549BF6E53A437541C5E596A8BD3" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_6DCEE74753B831174E921C5E596ABA98" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_March2017DropDownAssetsMember" xlink:label="loc_nrg_March2017DropDownAssetsMember_3AD2CDCF51E0C49631041C5E596A54F1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_6DCEE74753B831174E921C5E596ABA98" xlink:to="loc_nrg_March2017DropDownAssetsMember_3AD2CDCF51E0C49631041C5E596A54F1" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CvsrMember" xlink:label="loc_nrg_CvsrMember_834C0856EBBCD21DDA491C5E596A48A8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_6DCEE74753B831174E921C5E596ABA98" xlink:to="loc_nrg_CvsrMember_834C0856EBBCD21DDA491C5E596A48A8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_C84BE4CE86BCD6FE47251C5E596A6556" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0B8DB9A33BA886785B8E1C5E59683DAD" xlink:to="loc_us-gaap_StatementScenarioAxis_C84BE4CE86BCD6FE47251C5E596A6556" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_0B32DDFF2229B0B7077E1C5E596A141B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_C84BE4CE86BCD6FE47251C5E596A6556" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_0B32DDFF2229B0B7077E1C5E596A141B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_0B32DDFF2229B0B7077E1C5E596A141B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_C84BE4CE86BCD6FE47251C5E596A6556" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_0B32DDFF2229B0B7077E1C5E596A141B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioPreviouslyReportedMember" xlink:label="loc_us-gaap_ScenarioPreviouslyReportedMember_6B950E6C3C4E3DA339EE1C5E596A8A76" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScenarioUnspecifiedDomain_0B32DDFF2229B0B7077E1C5E596A141B" xlink:to="loc_us-gaap_ScenarioPreviouslyReportedMember_6B950E6C3C4E3DA339EE1C5E596A8A76" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_B12E3009D3D93CFDBE551C5E596B11A0" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0B8DB9A33BA886785B8E1C5E59683DAD" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_B12E3009D3D93CFDBE551C5E596B11A0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_A13F10F3100E59BA15501C5E596B0654_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_B12E3009D3D93CFDBE551C5E596B11A0" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_A13F10F3100E59BA15501C5E596B0654_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_A13F10F3100E59BA15501C5E596B0654" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_B12E3009D3D93CFDBE551C5E596B11A0" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_A13F10F3100E59BA15501C5E596B0654" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CvsrMember" xlink:label="loc_nrg_CvsrMember_6F071EE2EDA3FA53AC691C5E596BA2C9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_A13F10F3100E59BA15501C5E596B0654" xlink:to="loc_nrg_CvsrMember_6F071EE2EDA3FA53AC691C5E596BA2C9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_E3D2E96EC67D984F84901C5E596BF56B" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0B8DB9A33BA886785B8E1C5E59683DAD" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_E3D2E96EC67D984F84901C5E596BF56B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_FEE2C44BA63B646B03271C5E596BD0E9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_E3D2E96EC67D984F84901C5E596BF56B" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_FEE2C44BA63B646B03271C5E596BD0E9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_FEE2C44BA63B646B03271C5E596BD0E9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_E3D2E96EC67D984F84901C5E596BF56B" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_FEE2C44BA63B646B03271C5E596BD0E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipAxis" xlink:label="loc_us-gaap_OwnershipAxis_C43673C0ADDA681E635F1C5E596BD23D" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0B8DB9A33BA886785B8E1C5E59683DAD" xlink:to="loc_us-gaap_OwnershipAxis_C43673C0ADDA681E635F1C5E596BD23D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipDomain" xlink:label="loc_us-gaap_OwnershipDomain_32BA9D4B92CB1519442E1C5E596B6A15_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OwnershipAxis_C43673C0ADDA681E635F1C5E596BD23D" xlink:to="loc_us-gaap_OwnershipDomain_32BA9D4B92CB1519442E1C5E596B6A15_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipDomain" xlink:label="loc_us-gaap_OwnershipDomain_32BA9D4B92CB1519442E1C5E596B6A15" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OwnershipAxis_C43673C0ADDA681E635F1C5E596BD23D" xlink:to="loc_us-gaap_OwnershipDomain_32BA9D4B92CB1519442E1C5E596B6A15" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_F81BBCE042D1B7E394A71C5E596BF0B8" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0B8DB9A33BA886785B8E1C5E59683DAD" xlink:to="loc_us-gaap_StatementClassOfStockAxis_F81BBCE042D1B7E394A71C5E596BF0B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_8169E0BE2186D3E734351C5E596B8FB6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_F81BBCE042D1B7E394A71C5E596BF0B8" xlink:to="loc_us-gaap_ClassOfStockDomain_8169E0BE2186D3E734351C5E596B8FB6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_8169E0BE2186D3E734351C5E596B8FB6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_F81BBCE042D1B7E394A71C5E596BF0B8" xlink:to="loc_us-gaap_ClassOfStockDomain_8169E0BE2186D3E734351C5E596B8FB6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:label="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_A0C229AC3C36E5CF9F6A1C5E596B3EA9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E8D19BA53BFAC1B4CA741C5E596BC6F1" xlink:to="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_A0C229AC3C36E5CF9F6A1C5E596B3EA9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsNetGainsAndLosses" xlink:label="loc_us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsNetGainsAndLosses_C92CEBDD60FF5627392F1C5E596C5DF9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E8D19BA53BFAC1B4CA741C5E596BC6F1" xlink:to="loc_us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsNetGainsAndLosses_C92CEBDD60FF5627392F1C5E596C5DF9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_ACFB90D6A02A7FF919831C5E596C4580" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E8D19BA53BFAC1B4CA741C5E596BC6F1" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_ACFB90D6A02A7FF919831C5E596C4580" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PercentageOfOwnership" xlink:label="loc_nrg_PercentageOfOwnership_9BF6001B5C9368B4AC981C5E596CDC6F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E8D19BA53BFAC1B4CA741C5E596BC6F1" xlink:to="loc_nrg_PercentageOfOwnership_9BF6001B5C9368B4AC981C5E596CDC6F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_C32FE92A82322AF634D91C5E596CF817" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E8D19BA53BFAC1B4CA741C5E596BC6F1" xlink:to="loc_us-gaap_LongTermDebt_C32FE92A82322AF634D91C5E596CF817" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/BusinessAcquisitionsBusinessAcquisitionsMarch2017DropDowndetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3F08C76876D3A11C14311C5E5975E80D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3F08C76876D3A11C14311C5E5975E80D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_8DDA93597A76812381411C5E5975284B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3F08C76876D3A11C14311C5E5975E80D" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_8DDA93597A76812381411C5E5975284B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_551C5253B65BF00F76E61C5E5976BF79_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_8DDA93597A76812381411C5E5975284B" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_551C5253B65BF00F76E61C5E5976BF79_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_551C5253B65BF00F76E61C5E5976BF79" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_8DDA93597A76812381411C5E5975284B" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_551C5253B65BF00F76E61C5E5976BF79" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_March2017DropDownAssetsMember" xlink:label="loc_nrg_March2017DropDownAssetsMember_30AF5EA0D386F1FF615A1C5E59768CCD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_551C5253B65BF00F76E61C5E5976BF79" xlink:to="loc_nrg_March2017DropDownAssetsMember_30AF5EA0D386F1FF615A1C5E59768CCD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_F13C75F487B322B09B861C5E59769FFE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3F08C76876D3A11C14311C5E5975E80D" xlink:to="loc_us-gaap_StatementScenarioAxis_F13C75F487B322B09B861C5E59769FFE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_6E9E13B2A7D0A6BEAFC41C5E59760578_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_F13C75F487B322B09B861C5E59769FFE" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_6E9E13B2A7D0A6BEAFC41C5E59760578_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_6E9E13B2A7D0A6BEAFC41C5E59760578" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_F13C75F487B322B09B861C5E59769FFE" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_6E9E13B2A7D0A6BEAFC41C5E59760578" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioPreviouslyReportedMember" xlink:label="loc_us-gaap_ScenarioPreviouslyReportedMember_8EC812AB9BBC7F055F5E1C5E5976ADE1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScenarioUnspecifiedDomain_6E9E13B2A7D0A6BEAFC41C5E59760578" xlink:to="loc_us-gaap_ScenarioPreviouslyReportedMember_8EC812AB9BBC7F055F5E1C5E5976ADE1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_8439553D7346A4E87B311C5E59765E31" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3F08C76876D3A11C14311C5E5975E80D" xlink:to="loc_dei_LegalEntityAxis_8439553D7346A4E87B311C5E59765E31" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_17D7336F7DC0228BEBFC1C5E5976699D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_8439553D7346A4E87B311C5E59765E31" xlink:to="loc_dei_EntityDomain_17D7336F7DC0228BEBFC1C5E5976699D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_17D7336F7DC0228BEBFC1C5E5976699D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_8439553D7346A4E87B311C5E59765E31" xlink:to="loc_dei_EntityDomain_17D7336F7DC0228BEBFC1C5E5976699D" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NrgMember" xlink:label="loc_nrg_NrgMember_B88D4EEFDA06DB946B5B1C5E5977BA29" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_17D7336F7DC0228BEBFC1C5E5976699D" xlink:to="loc_nrg_NrgMember_B88D4EEFDA06DB946B5B1C5E5977BA29" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_437F50D6B9FEF93CC74A1C5E59777B86" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3F08C76876D3A11C14311C5E5975E80D" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_437F50D6B9FEF93CC74A1C5E59777B86" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_95C854AE83AB248057F81C5E5977404D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_437F50D6B9FEF93CC74A1C5E59777B86" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_95C854AE83AB248057F81C5E5977404D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_95C854AE83AB248057F81C5E5977404D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_437F50D6B9FEF93CC74A1C5E59777B86" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_95C854AE83AB248057F81C5E5977404D" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AguaCalienteMember" xlink:label="loc_nrg_AguaCalienteMember_C79F8E5951D8DA71F03E1C5E59774E4A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_95C854AE83AB248057F81C5E5977404D" xlink:to="loc_nrg_AguaCalienteMember_C79F8E5951D8DA71F03E1C5E59774E4A" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AguaCalienteBorrower2Member" xlink:label="loc_nrg_AguaCalienteBorrower2Member_3A7370DC43CF19E9934E1C5E597718FF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_95C854AE83AB248057F81C5E5977404D" xlink:to="loc_nrg_AguaCalienteBorrower2Member_3A7370DC43CF19E9934E1C5E597718FF" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_UtahPortfolioMember" xlink:label="loc_nrg_UtahPortfolioMember_0C4D7D35A88CF8FF3B681C5E59779769" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_95C854AE83AB248057F81C5E5977404D" xlink:to="loc_nrg_UtahPortfolioMember_0C4D7D35A88CF8FF3B681C5E59779769" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_March2017DropDownAssetsMember" xlink:label="loc_nrg_March2017DropDownAssetsMember_862DE4AC3954BD2CB87F1C5E5977B9C2" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_95C854AE83AB248057F81C5E5977404D" xlink:to="loc_nrg_March2017DropDownAssetsMember_862DE4AC3954BD2CB87F1C5E5977B9C2" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_August2017DropDownAssetsMember" xlink:label="loc_nrg_August2017DropDownAssetsMember_F49534BCDDC4A6EED9991C5E5977655B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_95C854AE83AB248057F81C5E5977404D" xlink:to="loc_nrg_August2017DropDownAssetsMember_F49534BCDDC4A6EED9991C5E5977655B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_69A4476835A013154C911C5E597803F3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_Revenues_69A4476835A013154C911C5E597803F3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_409E7B2D5A61A32B9D921C5E5978E4E7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_409E7B2D5A61A32B9D921C5E5978E4E7" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PercentageofNRGsOwnership" xlink:label="loc_nrg_PercentageofNRGsOwnership_5FCA7DBD9577C07CB2FC1C5E59780E1B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_nrg_PercentageofNRGsOwnership_5FCA7DBD9577C07CB2FC1C5E59780E1B" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PercentageOfOwnership" xlink:label="loc_nrg_PercentageOfOwnership_365024F3324104E92C081C5E59789F89" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_nrg_PercentageOfOwnership_365024F3324104E92C081C5E59789F89" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationCapacityMegawatts" xlink:label="loc_nrg_PowerGenerationCapacityMegawatts_D465A78BA949862D5BDE1C5E59789A01" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_nrg_PowerGenerationCapacityMegawatts_D465A78BA949862D5BDE1C5E59789A01" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerPurchaseAgreementPeriod" xlink:label="loc_nrg_PowerPurchaseAgreementPeriod_440973C90EFBE8E9FE521C5E5978DC29" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_nrg_PowerPurchaseAgreementPeriod_440973C90EFBE8E9FE521C5E5978DC29" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_RemainingPowerPurchaseAgreementterm" xlink:label="loc_nrg_RemainingPowerPurchaseAgreementterm_2B7FCF9AAA8260C7E5581C5E59786F07" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_nrg_RemainingPowerPurchaseAgreementterm_2B7FCF9AAA8260C7E5581C5E59786F07" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PercentageofCashAvailableforDistributions" xlink:label="loc_nrg_PercentageofCashAvailableforDistributions_B37C42870AC3E52F64691C5E597800B0" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_nrg_PercentageofCashAvailableforDistributions_B37C42870AC3E52F64691C5E597800B0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_EF48D62458320A45941C1C5E5978FBE9" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_EF48D62458320A45941C1C5E5978FBE9" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BusinessAcquisitionConsiderationTransferredWorkingCapital" xlink:label="loc_nrg_BusinessAcquisitionConsiderationTransferredWorkingCapital_CCD2BB1B748E727F71CF1C5E5978FD67" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_nrg_BusinessAcquisitionConsiderationTransferredWorkingCapital_CCD2BB1B748E727F71CF1C5E5978FD67" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonRecourseDebt" xlink:label="loc_us-gaap_NonRecourseDebt_ED77F7A8DC35BEE865501C5E5978E4D3" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_NonRecourseDebt_ED77F7A8DC35BEE865501C5E5978E4D3" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ProRateShareofDebtHeldbyUnconsolidatedAffiliates" xlink:label="loc_nrg_ProRateShareofDebtHeldbyUnconsolidatedAffiliates_1801874074BA560BD02A1C5E597852F9" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_nrg_ProRateShareofDebtHeldbyUnconsolidatedAffiliates_1801874074BA560BD02A1C5E597852F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsNetGainsAndLosses" xlink:label="loc_us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsNetGainsAndLosses_B2449451322A485B42181C5E5979E7C7" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsNetGainsAndLosses_B2449451322A485B42181C5E5979E7C7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:label="loc_us-gaap_EquityMethodInvestments_E8F1202EC9D966D50B801C5E59797885" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_EquityMethodInvestments_E8F1202EC9D966D50B801C5E59797885" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_9CDEE38F170ED86223061C5E5979CF40" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_9CDEE38F170ED86223061C5E5979CF40" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancialLiabilities" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancialLiabilities_E7AD20AAF6B0AD2D5ED51C5E5979E88D" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancialLiabilities_E7AD20AAF6B0AD2D5ED51C5E5979E88D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_6E1E1B5622792FF438B61C5E5979D54E" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_6E1E1B5622792FF438B61C5E5979D54E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_69182AC7FB9CCD618CC71C5E5979C838" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_69182AC7FB9CCD618CC71C5E5979C838" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_7CE0D0BE04D1DBCC0C891C5E59797C8C" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_7CE0D0BE04D1DBCC0C891C5E59797C8C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredFinanceCostsNet" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_D055E97786BB1407CD511C5E5979BF32" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_D055E97786BB1407CD511C5E5979BF32" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_9E9819CD0144B58A770C1C5E59792036" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_OperatingIncomeLoss_9E9819CD0144B58A770C1C5E59792036" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_00AB37FBD96564F8606F1C5E59798C17" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_ProfitLoss_00AB37FBD96564F8606F1C5E59798C17" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_87C85C45C1C3EBC9E62C1C5E5979F81C" xlink:type="locator" />
    <link:definitionArc order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_F5DE81F70DC37FF6F9701C5E59779C16" xlink:to="loc_us-gaap_NetIncomeLoss_87C85C45C1C3EBC9E62C1C5E5979F81C" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/BusinessAcquisitionsBusinessAcquisitionsNotes" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/BusinessAcquisitionsBusinessAcquisitionsNovember2017DropDownDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_915090692939B6C3E96D187E338E0374" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_915090692939B6C3E96D187E338E0374" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E24A430924A6BBDB9B71187E338E87CA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_915090692939B6C3E96D187E338E0374" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E24A430924A6BBDB9B71187E338E87CA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_C0CAD818C78D9E4B3B9E187E338E208C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E24A430924A6BBDB9B71187E338E87CA" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_C0CAD818C78D9E4B3B9E187E338E208C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_C0CAD818C78D9E4B3B9E187E338E208C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E24A430924A6BBDB9B71187E338E87CA" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_C0CAD818C78D9E4B3B9E187E338E208C" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_March2017DropDownAssetsMember" xlink:label="loc_nrg_March2017DropDownAssetsMember_A622D3FC0D82FF28B97B187E338F61E6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_C0CAD818C78D9E4B3B9E187E338E208C" xlink:to="loc_nrg_March2017DropDownAssetsMember_A622D3FC0D82FF28B97B187E338F61E6" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_August2017DropDownAssetsMember" xlink:label="loc_nrg_August2017DropDownAssetsMember_6BD024C54E511FA55187187E338FB0E1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_C0CAD818C78D9E4B3B9E187E338E208C" xlink:to="loc_nrg_August2017DropDownAssetsMember_6BD024C54E511FA55187187E338FB0E1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_F1929A497C9786DBF54B187E338FC5F8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_915090692939B6C3E96D187E338E0374" xlink:to="loc_us-gaap_StatementScenarioAxis_F1929A497C9786DBF54B187E338FC5F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_072D5A4F243FAAE854AB187E338F2C42_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_F1929A497C9786DBF54B187E338FC5F8" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_072D5A4F243FAAE854AB187E338F2C42_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_072D5A4F243FAAE854AB187E338F2C42" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_F1929A497C9786DBF54B187E338FC5F8" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_072D5A4F243FAAE854AB187E338F2C42" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioPreviouslyReportedMember" xlink:label="loc_us-gaap_ScenarioPreviouslyReportedMember_2B728D93F01A93E94089187E338FBE1E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScenarioUnspecifiedDomain_072D5A4F243FAAE854AB187E338F2C42" xlink:to="loc_us-gaap_ScenarioPreviouslyReportedMember_2B728D93F01A93E94089187E338FBE1E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_5CBBD522612E6431B0A8187E338FBB72" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_915090692939B6C3E96D187E338E0374" xlink:to="loc_us-gaap_DebtInstrumentAxis_5CBBD522612E6431B0A8187E338FBB72" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_95EE2CB401AC7CC6CFDC187E338F4EC4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_5CBBD522612E6431B0A8187E338FBB72" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_95EE2CB401AC7CC6CFDC187E338F4EC4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_95EE2CB401AC7CC6CFDC187E338F4EC4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_5CBBD522612E6431B0A8187E338FBB72" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_95EE2CB401AC7CC6CFDC187E338F4EC4" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_November2017DropDownAssetsMember" xlink:label="loc_nrg_November2017DropDownAssetsMember_2208848DED9E47426044187E339038CA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_95EE2CB401AC7CC6CFDC187E338F4EC4" xlink:to="loc_nrg_November2017DropDownAssetsMember_2208848DED9E47426044187E339038CA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_9F7C1B048CE5A407CC87187E3390D7B1" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_915090692939B6C3E96D187E338E0374" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_9F7C1B048CE5A407CC87187E3390D7B1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_BE6ABCAA20C48D7FAFA1187E339096DF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_9F7C1B048CE5A407CC87187E3390D7B1" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_BE6ABCAA20C48D7FAFA1187E339096DF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_BE6ABCAA20C48D7FAFA1187E339096DF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_9F7C1B048CE5A407CC87187E3390D7B1" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_BE6ABCAA20C48D7FAFA1187E339096DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_578FB99B15629A3D9E0C187E3390C219" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_BE6ABCAA20C48D7FAFA1187E339096DF" xlink:to="loc_us-gaap_SubsequentEventMember_578FB99B15629A3D9E0C187E3390C219" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_5FDD09D1CBECDF04D2E8187E33900B3B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_915090692939B6C3E96D187E338E0374" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_5FDD09D1CBECDF04D2E8187E33900B3B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7493E4892FF5FD45EE02187E33904990_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_5FDD09D1CBECDF04D2E8187E33900B3B" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7493E4892FF5FD45EE02187E33904990_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7493E4892FF5FD45EE02187E33904990" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_5FDD09D1CBECDF04D2E8187E33900B3B" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7493E4892FF5FD45EE02187E33904990" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_November2017DropDownAssetsMember" xlink:label="loc_nrg_November2017DropDownAssetsMember_568A7F9233C5C2A9EB55187E3390CC2E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7493E4892FF5FD45EE02187E33904990" xlink:to="loc_nrg_November2017DropDownAssetsMember_568A7F9233C5C2A9EB55187E3390CC2E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_2FCDDE756C7D3F6A955C187E3391610A" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_915090692939B6C3E96D187E338E0374" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_2FCDDE756C7D3F6A955C187E3391610A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_8058C5075D2B76D83A98187E3391198C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_2FCDDE756C7D3F6A955C187E3391610A" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_8058C5075D2B76D83A98187E3391198C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_8058C5075D2B76D83A98187E3391198C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_2FCDDE756C7D3F6A955C187E3391610A" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_8058C5075D2B76D83A98187E3391198C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipAxis" xlink:label="loc_us-gaap_OwnershipAxis_90FD5BEE00FE8B0DF9C7187E33917CDD" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_915090692939B6C3E96D187E338E0374" xlink:to="loc_us-gaap_OwnershipAxis_90FD5BEE00FE8B0DF9C7187E33917CDD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipDomain" xlink:label="loc_us-gaap_OwnershipDomain_6B04B665550CC8A9A3C1187E339141BB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OwnershipAxis_90FD5BEE00FE8B0DF9C7187E33917CDD" xlink:to="loc_us-gaap_OwnershipDomain_6B04B665550CC8A9A3C1187E339141BB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipDomain" xlink:label="loc_us-gaap_OwnershipDomain_6B04B665550CC8A9A3C1187E339141BB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OwnershipAxis_90FD5BEE00FE8B0DF9C7187E33917CDD" xlink:to="loc_us-gaap_OwnershipDomain_6B04B665550CC8A9A3C1187E339141BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_D698B85288ADAA1AFC69187E3391F078" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_915090692939B6C3E96D187E338E0374" xlink:to="loc_us-gaap_StatementClassOfStockAxis_D698B85288ADAA1AFC69187E3391F078" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_BB2F25B27DC41C58A623187E339118B5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_D698B85288ADAA1AFC69187E3391F078" xlink:to="loc_us-gaap_ClassOfStockDomain_BB2F25B27DC41C58A623187E339118B5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_BB2F25B27DC41C58A623187E339118B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_D698B85288ADAA1AFC69187E3391F078" xlink:to="loc_us-gaap_ClassOfStockDomain_BB2F25B27DC41C58A623187E339118B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_47C35E9DA6E07C4C3600187E339194A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_Revenues_47C35E9DA6E07C4C3600187E339194A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredFinanceCostsNet" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_552EC64D47414B8E4D25187E3392FA83" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_552EC64D47414B8E4D25187E3392FA83" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationCapacityMegawatts" xlink:label="loc_nrg_PowerGenerationCapacityMegawatts_F46A304E4BAD914C2A69187E33924F3A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_nrg_PowerGenerationCapacityMegawatts_F46A304E4BAD914C2A69187E33924F3A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_044A877C9FAC6D4FC359187E33924AEB" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_044A877C9FAC6D4FC359187E33924AEB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonRecourseDebt" xlink:label="loc_us-gaap_NonRecourseDebt_EB253B6644F3E5802008187E3392D9C5" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_NonRecourseDebt_EB253B6644F3E5802008187E3392D9C5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_001345907CC195D35D21187E33926CD1" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_001345907CC195D35D21187E33926CD1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_979C44A7CDBD68BAC8A6187E33921DC5" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_979C44A7CDBD68BAC8A6187E33921DC5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_64803D3E14ED0DDA7581187E33921C6D" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_64803D3E14ED0DDA7581187E33921C6D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_D3FB25799D08ED0F4495187E3392F216" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_D3FB25799D08ED0F4495187E3392F216" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancialLiabilities" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancialLiabilities_96B4116839A943663EBE187E33921828" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancialLiabilities_96B4116839A943663EBE187E33921828" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_EF76ED9E70A7E11BF6DB187E3393F521" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_EF76ED9E70A7E11BF6DB187E3393F521" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_0B8A0F2588292BD084B1187E33939B59" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_0B8A0F2588292BD084B1187E33939B59" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_3F83488E60766A5F02AC187E33936379" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_3F83488E60766A5F02AC187E33936379" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_9DBDD0B493691D407624187E3393A776" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_LongTermDebt_9DBDD0B493691D407624187E3393A776" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_B814865CF275AAEFEC34187E33935A4A" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_OperatingIncomeLoss_B814865CF275AAEFEC34187E33935A4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_3748E56797A8814D1C58187E3393C30C" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_ProfitLoss_3748E56797A8814D1C58187E3393C30C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_782FD9EEFF5182DD6045187E3393B041" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_782FD9EEFF5182DD6045187E3393B041" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_E3EE555D4DA3BE1DDD19187E33938943" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_E79259933F565FF10052187E339169EE" xlink:to="loc_us-gaap_NetIncomeLoss_E3EE555D4DA3BE1DDD19187E33938943" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/BusinessAcquisitionsBusinessAcquisitionsTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_1883DA2AB74AE88A0CDA187BDAA2E61C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_9AF190986C3B3FD3ABEA187BDAA0E386" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_1883DA2AB74AE88A0CDA187BDAA2E61C" xlink:to="loc_us-gaap_StatementTable_9AF190986C3B3FD3ABEA187BDAA0E386" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_6E3D5BB0BECDE4D2717D187BDAA1BBDE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9AF190986C3B3FD3ABEA187BDAA0E386" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_6E3D5BB0BECDE4D2717D187BDAA1BBDE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_753C064B0B043D1547B9187BDAA15715_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_6E3D5BB0BECDE4D2717D187BDAA1BBDE" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_753C064B0B043D1547B9187BDAA15715_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_753C064B0B043D1547B9187BDAA15715" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_6E3D5BB0BECDE4D2717D187BDAA1BBDE" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_753C064B0B043D1547B9187BDAA15715" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_November2017DropDownAssetsandAugust2017DropDownAssetsMember" xlink:label="loc_nrg_November2017DropDownAssetsandAugust2017DropDownAssetsMember_79E6CD1A1717A7560DCD187BDAA1652C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_753C064B0B043D1547B9187BDAA15715" xlink:to="loc_nrg_November2017DropDownAssetsandAugust2017DropDownAssetsMember_79E6CD1A1717A7560DCD187BDAA1652C" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BuckthornSolarDropDownAssetMember" xlink:label="loc_nrg_BuckthornSolarDropDownAssetMember_DEA5E824636580B09360187BDAA15232" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_753C064B0B043D1547B9187BDAA15715" xlink:to="loc_nrg_BuckthornSolarDropDownAssetMember_DEA5E824636580B09360187BDAA15232" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_November2017DropDownAssetsMember" xlink:label="loc_nrg_November2017DropDownAssetsMember_0B1D65F23E7620B26487187BDAA13026" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_753C064B0B043D1547B9187BDAA15715" xlink:to="loc_nrg_November2017DropDownAssetsMember_0B1D65F23E7620B26487187BDAA13026" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_March2017DropDownAssetsMember" xlink:label="loc_nrg_March2017DropDownAssetsMember_08C5E0B62701B5EF2D3D187BDAA28C13" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_753C064B0B043D1547B9187BDAA15715" xlink:to="loc_nrg_March2017DropDownAssetsMember_08C5E0B62701B5EF2D3D187BDAA28C13" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_16F76C7E50CFAC991F0C187BDAA2FB14" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_1883DA2AB74AE88A0CDA187BDAA2E61C" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_16F76C7E50CFAC991F0C187BDAA2FB14" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTextBlock" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTextBlock_DD2C3A4DA883236F4EDC187BDAA2227E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_1883DA2AB74AE88A0CDA187BDAA2E61C" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTextBlock_DD2C3A4DA883236F4EDC187BDAA2227E" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/BusinessAcquisitionsBusinessCombinationAugust2017DropDownDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_AEDB5D8C908BD6D98E99FD65C5304EB5" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_B6D83963CCEAC4472F21FD65C52F6390" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_AEDB5D8C908BD6D98E99FD65C5304EB5" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_B6D83963CCEAC4472F21FD65C52F6390" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_7AF81A8406818070626DFD65C52F2EFE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_B6D83963CCEAC4472F21FD65C52F6390" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_7AF81A8406818070626DFD65C52F2EFE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_225804E38E620A9D0DAEFD65C5305346_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_7AF81A8406818070626DFD65C52F2EFE" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_225804E38E620A9D0DAEFD65C5305346_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_225804E38E620A9D0DAEFD65C5305346" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_7AF81A8406818070626DFD65C52F2EFE" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_225804E38E620A9D0DAEFD65C5305346" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_August2017DropDownAssetsMember" xlink:label="loc_nrg_August2017DropDownAssetsMember_BAA919561239B9AC6C72FD65C530277A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_225804E38E620A9D0DAEFD65C5305346" xlink:to="loc_nrg_August2017DropDownAssetsMember_BAA919561239B9AC6C72FD65C530277A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_0A60EBDCE00494461B54FD65C530C629" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_B6D83963CCEAC4472F21FD65C52F6390" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_0A60EBDCE00494461B54FD65C530C629" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_21E3806A6D020AC5949DFD65C53031E5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_0A60EBDCE00494461B54FD65C530C629" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_21E3806A6D020AC5949DFD65C53031E5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_21E3806A6D020AC5949DFD65C53031E5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_0A60EBDCE00494461B54FD65C530C629" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_21E3806A6D020AC5949DFD65C53031E5" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_August2017DropDownAssetsMember" xlink:label="loc_nrg_August2017DropDownAssetsMember_5511A3ADF397553DE9ACFD65C530535C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_21E3806A6D020AC5949DFD65C53031E5" xlink:to="loc_nrg_August2017DropDownAssetsMember_5511A3ADF397553DE9ACFD65C530535C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_181E343F2CFF045810C2FD65C53070E1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_B6D83963CCEAC4472F21FD65C52F6390" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_181E343F2CFF045810C2FD65C53070E1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_553EBDD390FC08DA4C26FD65C530B898_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_181E343F2CFF045810C2FD65C53070E1" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_553EBDD390FC08DA4C26FD65C530B898_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_553EBDD390FC08DA4C26FD65C530B898" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_181E343F2CFF045810C2FD65C53070E1" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_553EBDD390FC08DA4C26FD65C530B898" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipAxis" xlink:label="loc_us-gaap_OwnershipAxis_A25647C7BE29A3EB5099FD65C530C226" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_B6D83963CCEAC4472F21FD65C52F6390" xlink:to="loc_us-gaap_OwnershipAxis_A25647C7BE29A3EB5099FD65C530C226" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipDomain" xlink:label="loc_us-gaap_OwnershipDomain_802A9DB69D67A8929494FD65C5301842_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OwnershipAxis_A25647C7BE29A3EB5099FD65C530C226" xlink:to="loc_us-gaap_OwnershipDomain_802A9DB69D67A8929494FD65C5301842_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipDomain" xlink:label="loc_us-gaap_OwnershipDomain_802A9DB69D67A8929494FD65C5301842" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OwnershipAxis_A25647C7BE29A3EB5099FD65C530C226" xlink:to="loc_us-gaap_OwnershipDomain_802A9DB69D67A8929494FD65C5301842" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_98EB8E0786187C419818FD65C530B0BA" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_B6D83963CCEAC4472F21FD65C52F6390" xlink:to="loc_us-gaap_StatementClassOfStockAxis_98EB8E0786187C419818FD65C530B0BA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_21BE49CA7C1A568AB3D6FD65C530E952_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_98EB8E0786187C419818FD65C530B0BA" xlink:to="loc_us-gaap_ClassOfStockDomain_21BE49CA7C1A568AB3D6FD65C530E952_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_21BE49CA7C1A568AB3D6FD65C530E952" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_98EB8E0786187C419818FD65C530B0BA" xlink:to="loc_us-gaap_ClassOfStockDomain_21BE49CA7C1A568AB3D6FD65C530E952" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:label="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_D8FA66BAAD868E189C29FD65C5305A4A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_AEDB5D8C908BD6D98E99FD65C5304EB5" xlink:to="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_D8FA66BAAD868E189C29FD65C5305A4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_B31273496C7F0F2283B9FD65C530656A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_AEDB5D8C908BD6D98E99FD65C5304EB5" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_B31273496C7F0F2283B9FD65C530656A" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BusinessAcquisitionConsiderationTransferredWorkingCapital" xlink:label="loc_nrg_BusinessAcquisitionConsiderationTransferredWorkingCapital_7EF38574CFFDB9148F54FD65C53098D8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_AEDB5D8C908BD6D98E99FD65C5304EB5" xlink:to="loc_nrg_BusinessAcquisitionConsiderationTransferredWorkingCapital_7EF38574CFFDB9148F54FD65C53098D8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_E0B7913B35DAE5454DE2FD65C53040D5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_AEDB5D8C908BD6D98E99FD65C5304EB5" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_E0B7913B35DAE5454DE2FD65C53040D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_494D0D40491DD8D9A2A4FD65C530BBF5" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_AEDB5D8C908BD6D98E99FD65C5304EB5" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_494D0D40491DD8D9A2A4FD65C530BBF5" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/CommitmentsAndContingenciesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/CommitmentsAndContingenciesNotes" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/CommitmentsAndContingenciesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/CondensedConsolidatedStatementsOfOperations" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_8BD60903F79721BBC3151C5E5A19A65A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_1A423F35759F662CA57D1C5E5A1854B0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_8BD60903F79721BBC3151C5E5A19A65A" xlink:to="loc_us-gaap_StatementTable_1A423F35759F662CA57D1C5E5A1854B0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_4D7A009F7CA22B6C30461C5E5A188067" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1A423F35759F662CA57D1C5E5A1854B0" xlink:to="loc_us-gaap_ConsolidationItemsAxis_4D7A009F7CA22B6C30461C5E5A188067" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_F0B0928C6B38F39B64941C5E5A18FEA0_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_4D7A009F7CA22B6C30461C5E5A188067" xlink:to="loc_us-gaap_ConsolidationItemsDomain_F0B0928C6B38F39B64941C5E5A18FEA0_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_F0B0928C6B38F39B64941C5E5A18FEA0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_4D7A009F7CA22B6C30461C5E5A188067" xlink:to="loc_us-gaap_ConsolidationItemsDomain_F0B0928C6B38F39B64941C5E5A18FEA0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_1C01B8A1495F4F9C261C1C5E5A183C75" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_F0B0928C6B38F39B64941C5E5A18FEA0" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_1C01B8A1495F4F9C261C1C5E5A183C75" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_6446B5CB302B89404FFC1C5E5A18865F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1A423F35759F662CA57D1C5E5A1854B0" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_6446B5CB302B89404FFC1C5E5A18865F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_0D6A14DA5F201A66CB0D1C5E5A18A3E7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6446B5CB302B89404FFC1C5E5A18865F" xlink:to="loc_us-gaap_EquityComponentDomain_0D6A14DA5F201A66CB0D1C5E5A18A3E7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_0D6A14DA5F201A66CB0D1C5E5A18A3E7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6446B5CB302B89404FFC1C5E5A18865F" xlink:to="loc_us-gaap_EquityComponentDomain_0D6A14DA5F201A66CB0D1C5E5A18A3E7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="loc_us-gaap_NoncontrollingInterestMember_79A1A529258D658047AF1C5E5A18166B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0D6A14DA5F201A66CB0D1C5E5A18A3E7" xlink:to="loc_us-gaap_NoncontrollingInterestMember_79A1A529258D658047AF1C5E5A18166B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_04FE61BB524A548293BF1C5E5A18AECC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1A423F35759F662CA57D1C5E5A1854B0" xlink:to="loc_us-gaap_StatementScenarioAxis_04FE61BB524A548293BF1C5E5A18AECC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_EE3EA7B502FE1A3C1D0F1C5E5A18EE02_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_04FE61BB524A548293BF1C5E5A18AECC" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_EE3EA7B502FE1A3C1D0F1C5E5A18EE02_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_EE3EA7B502FE1A3C1D0F1C5E5A18EE02" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_04FE61BB524A548293BF1C5E5A18AECC" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_EE3EA7B502FE1A3C1D0F1C5E5A18EE02" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationCondensedConsolidatingFinancialInformation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationCondensedConsolidatingFinancialInformationTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationCpBalanceSheetDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedBalanceSheetStatementTable" xlink:label="loc_us-gaap_CondensedBalanceSheetStatementTable_D4F7BFBECC2755963CC41C5E5716F669" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_CondensedBalanceSheetStatementTable_D4F7BFBECC2755963CC41C5E5716F669" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_B126240E2FC63ACB0BD71C5E5716CE47" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementTable_D4F7BFBECC2755963CC41C5E5716F669" xlink:to="loc_us-gaap_ConsolidationItemsAxis_B126240E2FC63ACB0BD71C5E5716CE47" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_2417F1478231A3C549D41C5E571697BE_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_B126240E2FC63ACB0BD71C5E5716CE47" xlink:to="loc_us-gaap_ConsolidationItemsDomain_2417F1478231A3C549D41C5E571697BE_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_2417F1478231A3C549D41C5E571697BE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_B126240E2FC63ACB0BD71C5E5716CE47" xlink:to="loc_us-gaap_ConsolidationItemsDomain_2417F1478231A3C549D41C5E571697BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_2D32E3509F92633469081C5E57169FE6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_2417F1478231A3C549D41C5E571697BE" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_2D32E3509F92633469081C5E57169FE6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_3B21A430F7326AE6A89B1C5E5716A063" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementTable_D4F7BFBECC2755963CC41C5E5716F669" xlink:to="loc_dei_LegalEntityAxis_3B21A430F7326AE6A89B1C5E5716A063" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_53102FD6D405FF9DB4921C5E57175A0A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_3B21A430F7326AE6A89B1C5E5716A063" xlink:to="loc_dei_EntityDomain_53102FD6D405FF9DB4921C5E57175A0A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_53102FD6D405FF9DB4921C5E57175A0A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_3B21A430F7326AE6A89B1C5E5716A063" xlink:to="loc_dei_EntityDomain_53102FD6D405FF9DB4921C5E57175A0A" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldLLCMember" xlink:label="loc_nrg_NRGYieldLLCMember_BCC8B749569BC7701E241C5E571781B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_53102FD6D405FF9DB4921C5E57175A0A" xlink:to="loc_nrg_NRGYieldLLCMember_BCC8B749569BC7701E241C5E571781B5" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldOperatingLLCMember" xlink:label="loc_nrg_NRGYieldOperatingLLCMember_E3EBD57C921906B454DC1C5E5717EAE7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_53102FD6D405FF9DB4921C5E57175A0A" xlink:to="loc_nrg_NRGYieldOperatingLLCMember_E3EBD57C921906B454DC1C5E5717EAE7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_D7F362CF123078E6412F1C5E571787DA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementTable_D4F7BFBECC2755963CC41C5E5716F669" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_D7F362CF123078E6412F1C5E571787DA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_C591F05FC4BAFB78C0A41C5E571727B0_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_D7F362CF123078E6412F1C5E571787DA" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_C591F05FC4BAFB78C0A41C5E571727B0_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_C591F05FC4BAFB78C0A41C5E571727B0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_D7F362CF123078E6412F1C5E571787DA" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_C591F05FC4BAFB78C0A41C5E571727B0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_B2A9858BCE24C3F803EF1C5E57174A3E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_C591F05FC4BAFB78C0A41C5E571727B0" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_B2A9858BCE24C3F803EF1C5E57174A3E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_9CD043D60CC0C449BB291C5E5717E5E0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_C591F05FC4BAFB78C0A41C5E571727B0" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_9CD043D60CC0C449BB291C5E5717E5E0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_456CF65041F86D9543A61C5E571D2F44" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_456CF65041F86D9543A61C5E571D2F44" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_B6626470C22705FA72E81C5E571D71ED" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_B6626470C22705FA72E81C5E571D71ED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_6ED18A3AFEC2B60570AE1C5E571D76F7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_6ED18A3AFEC2B60570AE1C5E571D76F7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_B93286F09E30B00E39CB1C5E571D7AF0" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_InventoryNet_B93286F09E30B00E39CB1C5E571D7AF0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeAssets" xlink:label="loc_us-gaap_DerivativeAssets_3E668F0842B39A6D91981C5E571D236C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_DerivativeAssets_3E668F0842B39A6D91981C5E571D236C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NotesAndLoansReceivableNetCurrent" xlink:label="loc_us-gaap_NotesAndLoansReceivableNetCurrent_12DF15F60260FA657F671C5E571D1A83" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_NotesAndLoansReceivableNetCurrent_12DF15F60260FA657F671C5E571D1A83" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_7A69C58C024E83CD95361C5E571D190D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_7A69C58C024E83CD95361C5E571D190D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_70E5B4EE6ECD42ACD15C1C5E571D4094" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_AssetsCurrent_70E5B4EE6ECD42ACD15C1C5E571D4094" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_087CAA729117F25EDBD31C5E571E3682" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_087CAA729117F25EDBD31C5E571E3682" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:label="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_0762F8C3D1A3A18F682F1C5E571EEB63" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_0762F8C3D1A3A18F682F1C5E571EEB63" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:label="loc_us-gaap_EquityMethodInvestments_803039D11D081BE2A8DB1C5E571E44B7" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_EquityMethodInvestments_803039D11D081BE2A8DB1C5E571E44B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_45F86DFE9455F4D4FBB91C5E571EB602" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_45F86DFE9455F4D4FBB91C5E571EB602" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeAssetsNoncurrent" xlink:label="loc_us-gaap_DerivativeAssetsNoncurrent_1D47CFAC3BD7701952ED1C5E571EB0AF" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_DerivativeAssetsNoncurrent_1D47CFAC3BD7701952ED1C5E571EB0AF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_AA4114BAEBCF7E0061C41C5E571E7D40" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_AA4114BAEBCF7E0061C41C5E571E7D40" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssets" xlink:label="loc_us-gaap_OtherAssets_35B66CA40B5C7F3DD6871C5E571EC143" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_OtherAssets_35B66CA40B5C7F3DD6871C5E571EC143" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_74B81CA2148C4F8A40191C5E571E1D06" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_Assets_74B81CA2148C4F8A40191C5E571E1D06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_6E2012308CE65DB585931C5E571EF54A" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_6E2012308CE65DB585931C5E571EF54A" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AffiliateCurrentDebt" xlink:label="loc_nrg_AffiliateCurrentDebt_79FCA193E0E6246CB17A1C5E571EEB53" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_nrg_AffiliateCurrentDebt_79FCA193E0E6246CB17A1C5E571EEB53" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_9E63D2E50279DB3441BE1C5E571F05BE" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_AccountsPayableCurrent_9E63D2E50279DB3441BE1C5E571F05BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToAffiliateCurrent" xlink:label="loc_us-gaap_DueToAffiliateCurrent_E088B5C515E42BC45C841C5E571FC548" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_DueToAffiliateCurrent_E088B5C515E42BC45C841C5E571FC548" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilitiesCurrent" xlink:label="loc_us-gaap_DerivativeLiabilitiesCurrent_430211D278188FA0C3971C5E571FE45A" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_DerivativeLiabilitiesCurrent_430211D278188FA0C3971C5E571FE45A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent_ABC788B3C1E8906180051C5E571FC97D" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesCurrent_ABC788B3C1E8906180051C5E571FC97D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_597DC2A92F3A816E58031C5E571F5760" xlink:type="locator" />
    <link:definitionArc order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_LiabilitiesCurrent_597DC2A92F3A816E58031C5E571F5760" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesNoncurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesNoncurrentAbstract_CE83396B10CB65A3FE2E1C5E571FD75A" xlink:type="locator" />
    <link:definitionArc order="24" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_LiabilitiesNoncurrentAbstract_CE83396B10CB65A3FE2E1C5E571FD75A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligations" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_15D944C651FA3BD0754A1C5E571FA5C5" xlink:type="locator" />
    <link:definitionArc order="25" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_15D944C651FA3BD0754A1C5E571FA5C5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToAffiliateNoncurrent" xlink:label="loc_us-gaap_DueToAffiliateNoncurrent_2AB04745C1535C9135E61C5E571F91EC" xlink:type="locator" />
    <link:definitionArc order="26" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_DueToAffiliateNoncurrent_2AB04745C1535C9135E61C5E571F91EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilitiesNoncurrent" xlink:label="loc_us-gaap_DerivativeLiabilitiesNoncurrent_4154F8E152729C21B3501C5E571F94D9" xlink:type="locator" />
    <link:definitionArc order="27" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_DerivativeLiabilitiesNoncurrent_4154F8E152729C21B3501C5E571F94D9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_9C9F34541B1704335E021C5E571F0B14" xlink:type="locator" />
    <link:definitionArc order="28" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_9C9F34541B1704335E021C5E571F0B14" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesNoncurrent" xlink:label="loc_us-gaap_LiabilitiesNoncurrent_4827CEFD8E2AF9511F701C5E5725CFF1" xlink:type="locator" />
    <link:definitionArc order="29" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_LiabilitiesNoncurrent_4827CEFD8E2AF9511F701C5E5725CFF1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_B84E4D4B1ED795CBD6661C5E57250E4A" xlink:type="locator" />
    <link:definitionArc order="30" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_Liabilities_B84E4D4B1ED795CBD6661C5E57250E4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_E347AC87CF406A3F6B3F1C5E5725A147" xlink:type="locator" />
    <link:definitionArc order="31" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_CommitmentsAndContingencies_E347AC87CF406A3F6B3F1C5E5725A147" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MembersCapital" xlink:label="loc_us-gaap_MembersCapital_32C42C3BA8D6148E7E351C5E572522ED" xlink:type="locator" />
    <link:definitionArc order="32" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_MembersCapital_32C42C3BA8D6148E7E351C5E572522ED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_B9CC01778ECA06F180EC1C5E572585BB" xlink:type="locator" />
    <link:definitionArc order="33" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_B9CC01778ECA06F180EC1C5E572585BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MembersEquityAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_MembersEquityAttributableToNoncontrollingInterest_4B7B19FFC69C8FBDE4FE1C5E5725A12A" xlink:type="locator" />
    <link:definitionArc order="34" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_MembersEquityAttributableToNoncontrollingInterest_4B7B19FFC69C8FBDE4FE1C5E5725A12A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_831AA17FF6AB48F106DB1C5E572579F4" xlink:type="locator" />
    <link:definitionArc order="35" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_831AA17FF6AB48F106DB1C5E572579F4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinorityInterest" xlink:label="loc_us-gaap_MinorityInterest_64461550E1EE67E6443C1C5E572526E5" xlink:type="locator" />
    <link:definitionArc order="36" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_MinorityInterest_64461550E1EE67E6443C1C5E572526E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MembersEquity" xlink:label="loc_us-gaap_MembersEquity_AD80BF6FA5F6768BA93D1C5E5725A2DF" xlink:type="locator" />
    <link:definitionArc order="37" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_MembersEquity_AD80BF6FA5F6768BA93D1C5E5725A2DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_FE34D258CF123233B11D1C5E57256FD0" xlink:type="locator" />
    <link:definitionArc order="38" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_9F278503F2D580B99B551C5E571761EF" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_FE34D258CF123233B11D1C5E57256FD0" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationCpCashFlowsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedCashFlowStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedCashFlowStatementTable" xlink:label="loc_us-gaap_CondensedCashFlowStatementTable_E36489D0982F81F4B1871C5D088D727B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_CondensedCashFlowStatementTable_E36489D0982F81F4B1871C5D088D727B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_30BB837DEFB50ED415A51C5D088DD238" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedCashFlowStatementTable_E36489D0982F81F4B1871C5D088D727B" xlink:to="loc_us-gaap_ConsolidationItemsAxis_30BB837DEFB50ED415A51C5D088DD238" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_A23D42A972B03D365C721C5D088DF26D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_30BB837DEFB50ED415A51C5D088DD238" xlink:to="loc_us-gaap_ConsolidationItemsDomain_A23D42A972B03D365C721C5D088DF26D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_A23D42A972B03D365C721C5D088DF26D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_30BB837DEFB50ED415A51C5D088DD238" xlink:to="loc_us-gaap_ConsolidationItemsDomain_A23D42A972B03D365C721C5D088DF26D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_8EF68D42A7B0794354781C5D088D448E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_A23D42A972B03D365C721C5D088DF26D" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_8EF68D42A7B0794354781C5D088D448E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_AB55AF67B087E142E6AB1C5D088E7A09" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedCashFlowStatementTable_E36489D0982F81F4B1871C5D088D727B" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_AB55AF67B087E142E6AB1C5D088E7A09" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_D5AC48F8B59EFCD9004C1C5D088E40F5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_AB55AF67B087E142E6AB1C5D088E7A09" xlink:to="loc_us-gaap_RelatedPartyDomain_D5AC48F8B59EFCD9004C1C5D088E40F5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_D5AC48F8B59EFCD9004C1C5D088E40F5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_AB55AF67B087E142E6AB1C5D088E7A09" xlink:to="loc_us-gaap_RelatedPartyDomain_D5AC48F8B59EFCD9004C1C5D088E40F5" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NrgMember" xlink:label="loc_nrg_NrgMember_77885491255E0FEE49431C5D088E8E7B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_D5AC48F8B59EFCD9004C1C5D088E40F5" xlink:to="loc_nrg_NrgMember_77885491255E0FEE49431C5D088E8E7B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_CABE598FACFDD287BC571C5D088E1437" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedCashFlowStatementTable_E36489D0982F81F4B1871C5D088D727B" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_CABE598FACFDD287BC571C5D088E1437" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_77AEA81F3159D6D293091C5D088E31AA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_CABE598FACFDD287BC571C5D088E1437" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_77AEA81F3159D6D293091C5D088E31AA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_77AEA81F3159D6D293091C5D088E31AA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_CABE598FACFDD287BC571C5D088E1437" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_77AEA81F3159D6D293091C5D088E31AA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_834154C18424B5E99C271C5D088F961C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedCashFlowStatementTable_E36489D0982F81F4B1871C5D088D727B" xlink:to="loc_dei_LegalEntityAxis_834154C18424B5E99C271C5D088F961C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_E07C3E483A05FD3E37091C5D088FC950_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_834154C18424B5E99C271C5D088F961C" xlink:to="loc_dei_EntityDomain_E07C3E483A05FD3E37091C5D088FC950_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_E07C3E483A05FD3E37091C5D088FC950" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_834154C18424B5E99C271C5D088F961C" xlink:to="loc_dei_EntityDomain_E07C3E483A05FD3E37091C5D088FC950" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldLLCMember" xlink:label="loc_nrg_NRGYieldLLCMember_D1F2FD72D234D74788781C5D088F1D91" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_E07C3E483A05FD3E37091C5D088FC950" xlink:to="loc_nrg_NRGYieldLLCMember_D1F2FD72D234D74788781C5D088F1D91" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldOperatingLLCMember" xlink:label="loc_nrg_NRGYieldOperatingLLCMember_41868183F8CE0F4DFBFC1C5D08941AC9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_E07C3E483A05FD3E37091C5D088FC950" xlink:to="loc_nrg_NRGYieldOperatingLLCMember_41868183F8CE0F4DFBFC1C5D08941AC9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_CD4E8841210238BADD061C5D0894B7E9" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedCashFlowStatementTable_E36489D0982F81F4B1871C5D088D727B" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_CD4E8841210238BADD061C5D0894B7E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_141915CE02AC0FA8140A1C5D08945FCB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_CD4E8841210238BADD061C5D0894B7E9" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_141915CE02AC0FA8140A1C5D08945FCB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_141915CE02AC0FA8140A1C5D08945FCB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_CD4E8841210238BADD061C5D0894B7E9" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_141915CE02AC0FA8140A1C5D08945FCB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_117448C193F8041363481C5D0895CE4C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_141915CE02AC0FA8140A1C5D08945FCB" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_117448C193F8041363481C5D0895CE4C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_E784EC6B06F025B7F6FC1C5D089536DB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_141915CE02AC0FA8140A1C5D08945FCB" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_E784EC6B06F025B7F6FC1C5D089536DB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromPaymentsToMinorityShareholders" xlink:label="loc_us-gaap_ProceedsFromPaymentsToMinorityShareholders_85C80F60CC25357FE5DF1C5D0895BFB9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_ProceedsFromPaymentsToMinorityShareholders_85C80F60CC25357FE5DF1C5D0895BFB9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_8141474AC049E5948A6C1C5D08953853" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_8141474AC049E5948A6C1C5D08953853" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_IntercompanyPaymentstoReceiptsfromConsolidatedSubsidiaries" xlink:label="loc_nrg_IntercompanyPaymentstoReceiptsfromConsolidatedSubsidiaries_E80DD3CC5A04965E0CF11C5D08958E34" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_nrg_IntercompanyPaymentstoReceiptsfromConsolidatedSubsidiaries_E80DD3CC5A04965E0CF11C5D08958E34" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PaymenttoAcquireBusinessunderCommonControl" xlink:label="loc_nrg_PaymenttoAcquireBusinessunderCommonControl_57D85BB1238A8DA824F61C5D08954567" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_nrg_PaymenttoAcquireBusinessunderCommonControl_57D85BB1238A8DA824F61C5D08954567" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_C09AF0B6A6A2C928437C1C5D0895F0C4" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_C09AF0B6A6A2C928437C1C5D0895F0C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInNotesReceivables" xlink:label="loc_us-gaap_IncreaseDecreaseInNotesReceivables_3734CCEC8884C9EFFE291C5D08956032" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_IncreaseDecreaseInNotesReceivables_3734CCEC8884C9EFFE291C5D08956032" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital" xlink:label="loc_us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital_0806902BCA56E4351DBA1C5D08952131" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital_0806902BCA56E4351DBA1C5D08952131" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesAndInterestInAffiliates" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesAndInterestInAffiliates_BBC1CC36E98F74584C961C5D08968BCF" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesAndInterestInAffiliates_BBC1CC36E98F74584C961C5D08968BCF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsForProceedsFromOtherInvestingActivities" xlink:label="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_5F5EA464A315596B45D21C5D08964383" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_5F5EA464A315596B45D21C5D08964383" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_97E349205A5BFC87FBAA1C5D08963811" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_97E349205A5BFC87FBAA1C5D08963811" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ProceedsFromPaymentsToIntercompanyLoans" xlink:label="loc_nrg_ProceedsFromPaymentsToIntercompanyLoans_1A951D81A7CF11F69E5D1C5D089648F5" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_nrg_ProceedsFromPaymentsToIntercompanyLoans_1A951D81A7CF11F69E5D1C5D089648F5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromMinorityShareholders" xlink:label="loc_us-gaap_ProceedsFromMinorityShareholders_A1342AECEC4C362E2C981C5D0896B7FF" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_ProceedsFromMinorityShareholders_A1342AECEC4C362E2C981C5D0896B7FF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsOfCapitalDistribution" xlink:label="loc_us-gaap_PaymentsOfCapitalDistribution_AE1274C58777669A1CFD1C5D08960442" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_PaymentsOfCapitalDistribution_AE1274C58777669A1CFD1C5D08960442" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_1A33639BA08344A6EC401C5D0896BF8B" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_1A33639BA08344A6EC401C5D0896BF8B" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PaymentsofProceedsfromdistributions" xlink:label="loc_nrg_PaymentsofProceedsfromdistributions_8F5B52A01ECE452F99981C5D08961BEB" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_nrg_PaymentsofProceedsfromdistributions_8F5B52A01ECE452F99981C5D08961BEB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_7042DCC76A28240DD7D01C5D0896E9C5" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_7042DCC76A28240DD7D01C5D0896E9C5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_608DCA41858AC88C67701C5D0896F44E" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_608DCA41858AC88C67701C5D0896F44E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_6E1BF62A9A2A118680351C5D08968688" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_6E1BF62A9A2A118680351C5D08968688" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_A98F45BEB8487328F4CC1C5D089C3E93" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_A98F45BEB8487328F4CC1C5D089C3E93" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromLinesOfCredit" xlink:label="loc_us-gaap_ProceedsFromLinesOfCredit_B8EE25661DAAFE2418E71C5D089CE80F" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_AC3D87A0425223AD78861C5D089559E2" xlink:to="loc_us-gaap_ProceedsFromLinesOfCredit_B8EE25661DAAFE2418E71C5D089CE80F" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationCpComprehensiveIncomeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedStatementOfIncomeCaptionsLineItems" xlink:label="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_BFF179C05CEF5C171F43FD65C45BDF6D" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedStatementOfComprehensiveIncomeTable" xlink:label="loc_us-gaap_CondensedStatementOfComprehensiveIncomeTable_3E2CCBF033A7712B6690FD65C45B6268" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_BFF179C05CEF5C171F43FD65C45BDF6D" xlink:to="loc_us-gaap_CondensedStatementOfComprehensiveIncomeTable_3E2CCBF033A7712B6690FD65C45B6268" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_C78C0A26FB1CC79BE93FFD65C45BA8C8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedStatementOfComprehensiveIncomeTable_3E2CCBF033A7712B6690FD65C45B6268" xlink:to="loc_us-gaap_ConsolidationItemsAxis_C78C0A26FB1CC79BE93FFD65C45BA8C8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_0795E8798128BBD2F176FD65C45B2714_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_C78C0A26FB1CC79BE93FFD65C45BA8C8" xlink:to="loc_us-gaap_ConsolidationItemsDomain_0795E8798128BBD2F176FD65C45B2714_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_0795E8798128BBD2F176FD65C45B2714" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_C78C0A26FB1CC79BE93FFD65C45BA8C8" xlink:to="loc_us-gaap_ConsolidationItemsDomain_0795E8798128BBD2F176FD65C45B2714" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_A1617FEC852E2F4F9719FD65C45B5C9E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_0795E8798128BBD2F176FD65C45B2714" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_A1617FEC852E2F4F9719FD65C45B5C9E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_52EC343F082F78D30B5CFD65C45BDA4E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedStatementOfComprehensiveIncomeTable_3E2CCBF033A7712B6690FD65C45B6268" xlink:to="loc_dei_LegalEntityAxis_52EC343F082F78D30B5CFD65C45BDA4E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_91C839C0410C38B61ADAFD65C45B3DD5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_52EC343F082F78D30B5CFD65C45BDA4E" xlink:to="loc_dei_EntityDomain_91C839C0410C38B61ADAFD65C45B3DD5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_91C839C0410C38B61ADAFD65C45B3DD5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_52EC343F082F78D30B5CFD65C45BDA4E" xlink:to="loc_dei_EntityDomain_91C839C0410C38B61ADAFD65C45B3DD5" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldLLCMember" xlink:label="loc_nrg_NRGYieldLLCMember_BF7D9A0FDF358C89CB1EFD65C45BB47E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_91C839C0410C38B61ADAFD65C45B3DD5" xlink:to="loc_nrg_NRGYieldLLCMember_BF7D9A0FDF358C89CB1EFD65C45BB47E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldOperatingLLCMember" xlink:label="loc_nrg_NRGYieldOperatingLLCMember_6DD0A5FE2AA728156FEBFD65C45BDFD7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_91C839C0410C38B61ADAFD65C45B3DD5" xlink:to="loc_nrg_NRGYieldOperatingLLCMember_6DD0A5FE2AA728156FEBFD65C45BDFD7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_905068CC5C79435FD11AFD65C45BCBC3" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedStatementOfComprehensiveIncomeTable_3E2CCBF033A7712B6690FD65C45B6268" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_905068CC5C79435FD11AFD65C45BCBC3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_641B7EB5468F69058458FD65C45B9189_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_905068CC5C79435FD11AFD65C45BCBC3" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_641B7EB5468F69058458FD65C45B9189_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_641B7EB5468F69058458FD65C45B9189" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_905068CC5C79435FD11AFD65C45BCBC3" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_641B7EB5468F69058458FD65C45B9189" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_3822BE9341AE56B959D8FD65C45B731B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_641B7EB5468F69058458FD65C45B9189" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_3822BE9341AE56B959D8FD65C45B731B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_E2DC71A389F382D57C04FD65C45B25D1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_641B7EB5468F69058458FD65C45B9189" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_E2DC71A389F382D57C04FD65C45B25D1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_F4FBC36869F05565924EFD65C45BD3F2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_BFF179C05CEF5C171F43FD65C45BDF6D" xlink:to="loc_us-gaap_ProfitLoss_F4FBC36869F05565924EFD65C45BD3F2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_437F608D448BAFE381F5FD65C45B098A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_BFF179C05CEF5C171F43FD65C45BDF6D" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_437F608D448BAFE381F5FD65C45B098A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_B830F388BC89076495E6FD65C45B99AC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_BFF179C05CEF5C171F43FD65C45BDF6D" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_B830F388BC89076495E6FD65C45B99AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_6E4F6F673D6DF44DFC60FD65C45B9EB7" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_BFF179C05CEF5C171F43FD65C45BDF6D" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_6E4F6F673D6DF44DFC60FD65C45B9EB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest_115A990EDBA81A7DB14CFD65C45BD932" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_BFF179C05CEF5C171F43FD65C45BDF6D" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest_115A990EDBA81A7DB14CFD65C45BD932" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_FF6637403937B4E94C68FD65C45BD283" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_BFF179C05CEF5C171F43FD65C45BDF6D" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_FF6637403937B4E94C68FD65C45BD283" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationCpIncomeStatementDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedIncomeStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedIncomeStatementTable" xlink:label="loc_us-gaap_CondensedIncomeStatementTable_8E69CC810A08E0D0AE921C5AD647AD0B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_CondensedIncomeStatementTable_8E69CC810A08E0D0AE921C5AD647AD0B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_DF5424ECCB81842664381C5AD647B1ED" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedIncomeStatementTable_8E69CC810A08E0D0AE921C5AD647AD0B" xlink:to="loc_us-gaap_DebtInstrumentAxis_DF5424ECCB81842664381C5AD647B1ED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_D05B12ED93391EA6CE3D1C5AD647EE59_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_DF5424ECCB81842664381C5AD647B1ED" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_D05B12ED93391EA6CE3D1C5AD647EE59_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_D05B12ED93391EA6CE3D1C5AD647EE59" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_DF5424ECCB81842664381C5AD647B1ED" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_D05B12ED93391EA6CE3D1C5AD647EE59" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_A5.00SeniorNotesduein2026Member" xlink:label="loc_nrg_A5.00SeniorNotesduein2026Member_D6BDD5F6A3D167214A1B1C5AD6470693" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_D05B12ED93391EA6CE3D1C5AD647EE59" xlink:to="loc_nrg_A5.00SeniorNotesduein2026Member_D6BDD5F6A3D167214A1B1C5AD6470693" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_7ACB35C6E23B4DE719AB1C5AD6477C3C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedIncomeStatementTable_8E69CC810A08E0D0AE921C5AD647AD0B" xlink:to="loc_us-gaap_ConsolidationItemsAxis_7ACB35C6E23B4DE719AB1C5AD6477C3C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_A36771904EFD2D6AC0621C5AD64770F3_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_7ACB35C6E23B4DE719AB1C5AD6477C3C" xlink:to="loc_us-gaap_ConsolidationItemsDomain_A36771904EFD2D6AC0621C5AD64770F3_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_A36771904EFD2D6AC0621C5AD64770F3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_7ACB35C6E23B4DE719AB1C5AD6477C3C" xlink:to="loc_us-gaap_ConsolidationItemsDomain_A36771904EFD2D6AC0621C5AD64770F3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_9B1265768646ED2F47771C5AD64803F7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_A36771904EFD2D6AC0621C5AD64770F3" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_9B1265768646ED2F47771C5AD64803F7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_A2393021EF4B8E640D8B1C5AD648FE59" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedIncomeStatementTable_8E69CC810A08E0D0AE921C5AD647AD0B" xlink:to="loc_dei_LegalEntityAxis_A2393021EF4B8E640D8B1C5AD648FE59" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_5196C531FAC8C06197D41C5AD6480E70_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_A2393021EF4B8E640D8B1C5AD648FE59" xlink:to="loc_dei_EntityDomain_5196C531FAC8C06197D41C5AD6480E70_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_5196C531FAC8C06197D41C5AD6480E70" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_A2393021EF4B8E640D8B1C5AD648FE59" xlink:to="loc_dei_EntityDomain_5196C531FAC8C06197D41C5AD6480E70" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldLLCMember" xlink:label="loc_nrg_NRGYieldLLCMember_6A830C6F3361862A40881C5AD648EE55" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_5196C531FAC8C06197D41C5AD6480E70" xlink:to="loc_nrg_NRGYieldLLCMember_6A830C6F3361862A40881C5AD648EE55" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldOperatingLLCMember" xlink:label="loc_nrg_NRGYieldOperatingLLCMember_ACD53D06C10A3A9B97461C5AD648190F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_5196C531FAC8C06197D41C5AD6480E70" xlink:to="loc_nrg_NRGYieldOperatingLLCMember_ACD53D06C10A3A9B97461C5AD648190F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_2F226441D8BAF7CBAC221C5AD648C0BF" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedIncomeStatementTable_8E69CC810A08E0D0AE921C5AD647AD0B" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_2F226441D8BAF7CBAC221C5AD648C0BF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_DC690B3C0A7A62FF323E1C5AD648A262_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_2F226441D8BAF7CBAC221C5AD648C0BF" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_DC690B3C0A7A62FF323E1C5AD648A262_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_DC690B3C0A7A62FF323E1C5AD648A262" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_2F226441D8BAF7CBAC221C5AD648C0BF" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_DC690B3C0A7A62FF323E1C5AD648A262" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_DCDA17C6EFD2B8DEBC9F1C5AD648621F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_DC690B3C0A7A62FF323E1C5AD648A262" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_DCDA17C6EFD2B8DEBC9F1C5AD648621F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_9F26C2FCB151B2CD1C681C5AD64876CC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_DC690B3C0A7A62FF323E1C5AD648A262" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_9F26C2FCB151B2CD1C681C5AD64876CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SeniorNotes" xlink:label="loc_us-gaap_SeniorNotes_E12137C2B26BA8D16A0C1C5AD64811BC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_SeniorNotes_E12137C2B26BA8D16A0C1C5AD64811BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_B0F0F9A3E21D9822C4321C5AD64912EC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_Revenues_B0F0F9A3E21D9822C4321C5AD64912EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingCostsAndExpensesAbstract" xlink:label="loc_us-gaap_OperatingCostsAndExpensesAbstract_E5AF81C8FAA9E6F5F8B81C5AD64927A8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_OperatingCostsAndExpensesAbstract_E5AF81C8FAA9E6F5F8B81C5AD64927A8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostOfRevenue" xlink:label="loc_us-gaap_CostOfRevenue_672508559BCB672C48F81C5AD6494FB7" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_CostOfRevenue_672508559BCB672C48F81C5AD6494FB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_82201BAFDBAA51058AA21C5AD6492008" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_82201BAFDBAA51058AA21C5AD6492008" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_9237409D9A24CE7BCE4A1C5AD649DED0" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_9237409D9A24CE7BCE4A1C5AD649DED0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostsAndExpenses" xlink:label="loc_us-gaap_CostsAndExpenses_8752700C989547151BCA1C5AD6497EB4" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_CostsAndExpenses_8752700C989547151BCA1C5AD6497EB4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_789C59E70C19EE8F2FEA1C5AD6498877" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_OperatingIncomeLoss_789C59E70C19EE8F2FEA1C5AD6498877" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostsAndExpensesAbstract" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_B2596D9FCBE849A1A85F1C5AD6497805" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_B2596D9FCBE849A1A85F1C5AD6497805" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_EquityInEarningsOfConsolidatedSubsidiaries" xlink:label="loc_nrg_EquityInEarningsOfConsolidatedSubsidiaries_BA7E104384BB6FC928BB1C5AD64988FC" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_nrg_EquityInEarningsOfConsolidatedSubsidiaries_BA7E104384BB6FC928BB1C5AD64988FC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_40D957B14B8B515D12AA1C5AD649B604" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_40D957B14B8B515D12AA1C5AD649B604" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_59270553951D6C6A473F1C5AD649AD06" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_59270553951D6C6A473F1C5AD649AD06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_EFCA4A9E9123FDB6FCCB1C5AD64F880F" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_InterestExpense_EFCA4A9E9123FDB6FCCB1C5AD64F880F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_BFD1E7100DD697259A661C5AD64F337C" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_BFD1E7100DD697259A661C5AD64F337C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_6437C21A903D2A9327FF1C5AD64F6324" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_ProfitLoss_6437C21A903D2A9327FF1C5AD64F6324" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_79309F706328626546BB1C5AD64FAABA" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_79309F706328626546BB1C5AD64FAABA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_F85C40138C0C7CD342441C5AD64F4B60" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_2C02B603FCE028CEE0971C5AD648BD87" xlink:to="loc_us-gaap_NetIncomeLoss_F85C40138C0C7CD342441C5AD64F4B60" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationPpBalanceSheetDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedBalanceSheetStatementTable" xlink:label="loc_us-gaap_CondensedBalanceSheetStatementTable_25EA7254F8EDC25751801C5E56967AEE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_CondensedBalanceSheetStatementTable_25EA7254F8EDC25751801C5E56967AEE" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_F339FC47DC69C14829861C5E56969C2D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementTable_25EA7254F8EDC25751801C5E56967AEE" xlink:to="loc_us-gaap_ConsolidationItemsAxis_F339FC47DC69C14829861C5E56969C2D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_686E5BB9FA8E804A8F1A1C5E5696F62B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_F339FC47DC69C14829861C5E56969C2D" xlink:to="loc_us-gaap_ConsolidationItemsDomain_686E5BB9FA8E804A8F1A1C5E5696F62B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_686E5BB9FA8E804A8F1A1C5E5696F62B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_F339FC47DC69C14829861C5E56969C2D" xlink:to="loc_us-gaap_ConsolidationItemsDomain_686E5BB9FA8E804A8F1A1C5E5696F62B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_065F6538AA165EEA794F1C5E5696B564" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_686E5BB9FA8E804A8F1A1C5E5696F62B" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_065F6538AA165EEA794F1C5E5696B564" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_0B4AD9F7813C98A46CA11C5E569712AE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementTable_25EA7254F8EDC25751801C5E56967AEE" xlink:to="loc_dei_LegalEntityAxis_0B4AD9F7813C98A46CA11C5E569712AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_AD2474D186FDAC8F80211C5E5697B3E5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_0B4AD9F7813C98A46CA11C5E569712AE" xlink:to="loc_dei_EntityDomain_AD2474D186FDAC8F80211C5E5697B3E5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_AD2474D186FDAC8F80211C5E5697B3E5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_0B4AD9F7813C98A46CA11C5E569712AE" xlink:to="loc_dei_EntityDomain_AD2474D186FDAC8F80211C5E5697B3E5" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldLLCMember" xlink:label="loc_nrg_NRGYieldLLCMember_75A9932D55B2FB894C6C1C5E56976427" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_AD2474D186FDAC8F80211C5E5697B3E5" xlink:to="loc_nrg_NRGYieldLLCMember_75A9932D55B2FB894C6C1C5E56976427" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldOperatingLLCMember" xlink:label="loc_nrg_NRGYieldOperatingLLCMember_79FF4B487A59CBE8FC2B1C5E56976750" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_AD2474D186FDAC8F80211C5E5697B3E5" xlink:to="loc_nrg_NRGYieldOperatingLLCMember_79FF4B487A59CBE8FC2B1C5E56976750" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_A9C99B6B7837C817360D1C5E569CC65F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementTable_25EA7254F8EDC25751801C5E56967AEE" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_A9C99B6B7837C817360D1C5E569CC65F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_CCB477EDF13F6127A95D1C5E569D5A03_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_A9C99B6B7837C817360D1C5E569CC65F" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_CCB477EDF13F6127A95D1C5E569D5A03_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_CCB477EDF13F6127A95D1C5E569D5A03" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_A9C99B6B7837C817360D1C5E569CC65F" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_CCB477EDF13F6127A95D1C5E569D5A03" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_373738CF097A24DDF0771C5E569DDC6E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_CCB477EDF13F6127A95D1C5E569D5A03" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_373738CF097A24DDF0771C5E569DDC6E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_882ACD11135008DDA7E41C5E569DCDB3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_CCB477EDF13F6127A95D1C5E569D5A03" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_882ACD11135008DDA7E41C5E569DCDB3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_8B86ACDA1D1F80CC63EC1C5E569EECB6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_8B86ACDA1D1F80CC63EC1C5E569EECB6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_7E3306B902E5DFE676F11C5E569E4E7F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_7E3306B902E5DFE676F11C5E569E4E7F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_7AA94E45E830D1EE1DAF1C5E569E149B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_7AA94E45E830D1EE1DAF1C5E569E149B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_2E354F9D63D7A769ADD11C5E569E3D43" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_InventoryNet_2E354F9D63D7A769ADD11C5E569E3D43" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NotesAndLoansReceivableNetCurrent" xlink:label="loc_us-gaap_NotesAndLoansReceivableNetCurrent_CFC9871DD2B275CB59C31C5E569EB76E" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_NotesAndLoansReceivableNetCurrent_CFC9871DD2B275CB59C31C5E569EB76E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_B3A5A5CDC9EFCB1E39171C5E569F1F58" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_B3A5A5CDC9EFCB1E39171C5E569F1F58" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_DA21CE5CA1C89EB9B9261C5E569F4BC2" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_AssetsCurrent_DA21CE5CA1C89EB9B9261C5E569F4BC2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_20E8D95F294B1023FB811C5E569F9F77" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_20E8D95F294B1023FB811C5E569F9F77" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:label="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_8056E1649F9F06E2CE601C5E569FA1CF" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_8056E1649F9F06E2CE601C5E569FA1CF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:label="loc_us-gaap_EquityMethodInvestments_4B244C02F2D703BD69B81C5E569FCEB3" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_EquityMethodInvestments_4B244C02F2D703BD69B81C5E569FCEB3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_95353810CF6EF15D05AC1C5E569FADFD" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_95353810CF6EF15D05AC1C5E569FADFD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentsAndHedgesNoncurrent" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgesNoncurrent_C577526B5A906F1408B21C5E569FBC61" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_DerivativeInstrumentsAndHedgesNoncurrent_C577526B5A906F1408B21C5E569FBC61" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_50390BCC3D034E7165921C5E56A029FC" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_50390BCC3D034E7165921C5E56A029FC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssets" xlink:label="loc_us-gaap_OtherAssets_378B5DF2EFE60AF0F87E1C5E56A007B4" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_OtherAssets_378B5DF2EFE60AF0F87E1C5E56A007B4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_E3D1499BA2F966E950C91C5E56A0444F" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_Assets_E3D1499BA2F966E950C91C5E56A0444F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_BA05BCCFE5320484823D1C5E56A096B7" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_BA05BCCFE5320484823D1C5E56A096B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_23E93D1C917B13B6C8961C5E56A0EF7B" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_AccountsPayableCurrent_23E93D1C917B13B6C8961C5E56A0EF7B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToAffiliateCurrent" xlink:label="loc_us-gaap_DueToAffiliateCurrent_1BD67883F94EC95FB8041C5E56A0673D" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_DueToAffiliateCurrent_1BD67883F94EC95FB8041C5E56A0673D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilitiesCurrent" xlink:label="loc_us-gaap_DerivativeLiabilitiesCurrent_B80048D6712E11531D161C5E56A074E6" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_DerivativeLiabilitiesCurrent_B80048D6712E11531D161C5E56A074E6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent_6F4F410795A23AF92ADA1C5E56A1490A" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesCurrent_6F4F410795A23AF92ADA1C5E56A1490A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_5EC2DE5A1FBD4CC7E9E51C5E56A626D4" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_LiabilitiesCurrent_5EC2DE5A1FBD4CC7E9E51C5E56A626D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesNoncurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesNoncurrentAbstract_6C6ED2F5EE7B7C6107751C5E56A67515" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_LiabilitiesNoncurrentAbstract_6C6ED2F5EE7B7C6107751C5E56A67515" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligations" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_A90312783D95E6AF73571C5E56A669D5" xlink:type="locator" />
    <link:definitionArc order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_A90312783D95E6AF73571C5E56A669D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToAffiliateNoncurrent" xlink:label="loc_us-gaap_DueToAffiliateNoncurrent_EE62F7E4F4FAEBC9B5241C5E56A74985" xlink:type="locator" />
    <link:definitionArc order="24" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_DueToAffiliateNoncurrent_EE62F7E4F4FAEBC9B5241C5E56A74985" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilitiesNoncurrent" xlink:label="loc_us-gaap_DerivativeLiabilitiesNoncurrent_B86EF9F8F0AA761EF49B1C5E56A7B839" xlink:type="locator" />
    <link:definitionArc order="25" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_DerivativeLiabilitiesNoncurrent_B86EF9F8F0AA761EF49B1C5E56A7B839" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_5AB3218CF324BFFC30DF1C5E56A74E8E" xlink:type="locator" />
    <link:definitionArc order="26" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_5AB3218CF324BFFC30DF1C5E56A74E8E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesNoncurrent" xlink:label="loc_us-gaap_LiabilitiesNoncurrent_E6DF33A3A73AB76B56F11C5E56A7E25A" xlink:type="locator" />
    <link:definitionArc order="27" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_LiabilitiesNoncurrent_E6DF33A3A73AB76B56F11C5E56A7E25A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_68014C2374FFA6AE7B881C5E56A7872F" xlink:type="locator" />
    <link:definitionArc order="28" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_Liabilities_68014C2374FFA6AE7B881C5E56A7872F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_C0308094BC24423BA66A1C5E56A7FDB9" xlink:type="locator" />
    <link:definitionArc order="29" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_CommitmentsAndContingencies_C0308094BC24423BA66A1C5E56A7FDB9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MembersCapital" xlink:label="loc_us-gaap_MembersCapital_22E62975B5918B4315DA1C5E56A712B2" xlink:type="locator" />
    <link:definitionArc order="30" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_MembersCapital_22E62975B5918B4315DA1C5E56A712B2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_B07BE229675B4E9B83DB1C5E56A80CCF" xlink:type="locator" />
    <link:definitionArc order="31" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_B07BE229675B4E9B83DB1C5E56A80CCF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_1C88325988473E9F41A81C5E56A9E686" xlink:type="locator" />
    <link:definitionArc order="32" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_1C88325988473E9F41A81C5E56A9E686" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinorityInterest" xlink:label="loc_us-gaap_MinorityInterest_A0080E7816B702FD0F1C1C5E56A91BC6" xlink:type="locator" />
    <link:definitionArc order="33" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_MinorityInterest_A0080E7816B702FD0F1C1C5E56A91BC6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MembersEquity" xlink:label="loc_us-gaap_MembersEquity_6DCE501E8B34BD5093541C5E56A9926F" xlink:type="locator" />
    <link:definitionArc order="34" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_MembersEquity_6DCE501E8B34BD5093541C5E56A9926F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_8B0C7DAF6EE278798BA11C5E56A97F3B" xlink:type="locator" />
    <link:definitionArc order="35" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_8B0C7DAF6EE278798BA11C5E56A97F3B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeAssets" xlink:label="loc_us-gaap_DerivativeAssets_EE3AAE01BC72652131F11C5E56A9B40C" xlink:type="locator" />
    <link:definitionArc order="36" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_B3A955F23E5AA84D03A01C5E569E6BBD" xlink:to="loc_us-gaap_DerivativeAssets_EE3AAE01BC72652131F11C5E56A9B40C" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationPpCashFlowsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedCashFlowStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedCashFlowStatementTable" xlink:label="loc_us-gaap_CondensedCashFlowStatementTable_A041E335E522243F09B5187F2D4295F7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_CondensedCashFlowStatementTable_A041E335E522243F09B5187F2D4295F7" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_75BB68B9579EAD26F437187F2D4203BE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedCashFlowStatementTable_A041E335E522243F09B5187F2D4295F7" xlink:to="loc_us-gaap_ConsolidationItemsAxis_75BB68B9579EAD26F437187F2D4203BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_D1938B1595CB49743E93187F2D43173E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_75BB68B9579EAD26F437187F2D4203BE" xlink:to="loc_us-gaap_ConsolidationItemsDomain_D1938B1595CB49743E93187F2D43173E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_D1938B1595CB49743E93187F2D43173E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_75BB68B9579EAD26F437187F2D4203BE" xlink:to="loc_us-gaap_ConsolidationItemsDomain_D1938B1595CB49743E93187F2D43173E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_7CF87A0F71155FD699CB187F2D43EED9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_D1938B1595CB49743E93187F2D43173E" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_7CF87A0F71155FD699CB187F2D43EED9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_01C9E1A6E54AE8131148187F2D437489" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedCashFlowStatementTable_A041E335E522243F09B5187F2D4295F7" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_01C9E1A6E54AE8131148187F2D437489" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_F1A9346960E52EEA21B6187F2D436488_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_01C9E1A6E54AE8131148187F2D437489" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_F1A9346960E52EEA21B6187F2D436488_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_F1A9346960E52EEA21B6187F2D436488" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_01C9E1A6E54AE8131148187F2D437489" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_F1A9346960E52EEA21B6187F2D436488" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_DropDownAssetsMember" xlink:label="loc_nrg_DropDownAssetsMember_4D97F6E4A16C5E6BB0E8187F2D4306C6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_F1A9346960E52EEA21B6187F2D436488" xlink:to="loc_nrg_DropDownAssetsMember_4D97F6E4A16C5E6BB0E8187F2D4306C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_C4BA1D5645A02D422228187F2D43693A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedCashFlowStatementTable_A041E335E522243F09B5187F2D4295F7" xlink:to="loc_dei_LegalEntityAxis_C4BA1D5645A02D422228187F2D43693A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_91A7E153C92A169B8BF5187F2D43BE88_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_C4BA1D5645A02D422228187F2D43693A" xlink:to="loc_dei_EntityDomain_91A7E153C92A169B8BF5187F2D43BE88_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_91A7E153C92A169B8BF5187F2D43BE88" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_C4BA1D5645A02D422228187F2D43693A" xlink:to="loc_dei_EntityDomain_91A7E153C92A169B8BF5187F2D43BE88" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldLLCMember" xlink:label="loc_nrg_NRGYieldLLCMember_CEDF5B1E4FC6756FEC9E187F2D44E90B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_91A7E153C92A169B8BF5187F2D43BE88" xlink:to="loc_nrg_NRGYieldLLCMember_CEDF5B1E4FC6756FEC9E187F2D44E90B" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldOperatingLLCMember" xlink:label="loc_nrg_NRGYieldOperatingLLCMember_D537755D60021FBFCECE187F2D44C6AB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_91A7E153C92A169B8BF5187F2D43BE88" xlink:to="loc_nrg_NRGYieldOperatingLLCMember_D537755D60021FBFCECE187F2D44C6AB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_AB358BB26CFB26714285187F2D44E5A5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedCashFlowStatementTable_A041E335E522243F09B5187F2D4295F7" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_AB358BB26CFB26714285187F2D44E5A5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_14C82DDCD9E0EDACA3DE187F2D441114_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_AB358BB26CFB26714285187F2D44E5A5" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_14C82DDCD9E0EDACA3DE187F2D441114_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_14C82DDCD9E0EDACA3DE187F2D441114" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_AB358BB26CFB26714285187F2D44E5A5" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_14C82DDCD9E0EDACA3DE187F2D441114" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_724DC16117326DC53D05187F2D4496FA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_14C82DDCD9E0EDACA3DE187F2D441114" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_724DC16117326DC53D05187F2D4496FA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_34B08143E1D863EDC222187F2D44225D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_14C82DDCD9E0EDACA3DE187F2D441114" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_34B08143E1D863EDC222187F2D44225D" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PaymenttoAcquireBusinessunderCommonControl" xlink:label="loc_nrg_PaymenttoAcquireBusinessunderCommonControl_8922222FD3F08601CB2A187F2D4506FF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_nrg_PaymenttoAcquireBusinessunderCommonControl_8922222FD3F08601CB2A187F2D4506FF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_BE5A9A11AD0367C6D470187F2D45C101" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_BE5A9A11AD0367C6D470187F2D45C101" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromMinorityShareholders" xlink:label="loc_us-gaap_ProceedsFromMinorityShareholders_4EF4613344C2B749D897187F2D456B27" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_ProceedsFromMinorityShareholders_4EF4613344C2B749D897187F2D456B27" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_IntercompanyPaymentstoReceiptsfromConsolidatedSubsidiaries" xlink:label="loc_nrg_IntercompanyPaymentstoReceiptsfromConsolidatedSubsidiaries_2324F8803C8DAFD56CE3187F2D45D490" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_nrg_IntercompanyPaymentstoReceiptsfromConsolidatedSubsidiaries_2324F8803C8DAFD56CE3187F2D45D490" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_483C9F7A8830F14C0ECA187F2D4535F7" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_483C9F7A8830F14C0ECA187F2D4535F7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInNotesReceivables" xlink:label="loc_us-gaap_IncreaseDecreaseInNotesReceivables_A540D0A116A7CDF022A2187F2D4586DD" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_IncreaseDecreaseInNotesReceivables_A540D0A116A7CDF022A2187F2D4586DD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital" xlink:label="loc_us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital_E9A7C42AF8A4D4E2F59E187F2D45F828" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital_E9A7C42AF8A4D4E2F59E187F2D45F828" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesAndInterestInAffiliates" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesAndInterestInAffiliates_6E05D4AE3089A6B44016187F2D45842A" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesAndInterestInAffiliates_6E05D4AE3089A6B44016187F2D45842A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_DD7557816023815F3B4E187F2D46E4C8" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_DD7557816023815F3B4E187F2D46E4C8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsOfCapitalDistribution" xlink:label="loc_us-gaap_PaymentsOfCapitalDistribution_9CF5843B400D455EBB68187F2D46AB92" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_PaymentsOfCapitalDistribution_9CF5843B400D455EBB68187F2D46AB92" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_8B738B62A9BB6B633131187F2D46AF65" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_8B738B62A9BB6B633131187F2D46AF65" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ProceedsFromPaymentsToIntercompanyLoans" xlink:label="loc_nrg_ProceedsFromPaymentsToIntercompanyLoans_626C2FD9FBF24FC24E0E187F2D461F6E" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_nrg_ProceedsFromPaymentsToIntercompanyLoans_626C2FD9FBF24FC24E0E187F2D461F6E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsOfDividends" xlink:label="loc_us-gaap_PaymentsOfDividends_6B68B55CD8F117D07A34187F2D46D2F1" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_PaymentsOfDividends_6B68B55CD8F117D07A34187F2D46D2F1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_46DA1D911D82BB6FDBBF187F2D46ABD6" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_46DA1D911D82BB6FDBBF187F2D46ABD6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsOfDebtIssuanceCosts" xlink:label="loc_us-gaap_PaymentsOfDebtIssuanceCosts_0B7031B4B0EA273148BF187F2D465094" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_PaymentsOfDebtIssuanceCosts_0B7031B4B0EA273148BF187F2D465094" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromLinesOfCredit" xlink:label="loc_us-gaap_ProceedsFromLinesOfCredit_19B43F7C2E779FB53BAB187F2D46176C" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_ProceedsFromLinesOfCredit_19B43F7C2E779FB53BAB187F2D46176C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RepaymentsOfLongTermDebt" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_531FCE98663956FC94B8187F2D479ECF" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_531FCE98663956FC94B8187F2D479ECF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_14B40DD48DD50D155E9D187F2D476651" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_14B40DD48DD50D155E9D187F2D476651" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_7079A7F024E6895CF625187F2D477A6E" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_7079A7F024E6895CF625187F2D477A6E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_C16B686A006A80B02181187F2D47DE33" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_25B7F6DCD94AC46CBB1C187F2D445F73" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_C16B686A006A80B02181187F2D47DE33" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationPpComprehensiveIncomeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedStatementOfIncomeCaptionsLineItems" xlink:label="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_FA71A545177A6562572EFD65C43756FB" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedStatementOfComprehensiveIncomeTable" xlink:label="loc_us-gaap_CondensedStatementOfComprehensiveIncomeTable_993EBBAAE4ED26F810DAFD65C4367413" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_FA71A545177A6562572EFD65C43756FB" xlink:to="loc_us-gaap_CondensedStatementOfComprehensiveIncomeTable_993EBBAAE4ED26F810DAFD65C4367413" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_CEBA92B2A4D8662B926FFD65C436BD4C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedStatementOfComprehensiveIncomeTable_993EBBAAE4ED26F810DAFD65C4367413" xlink:to="loc_us-gaap_ConsolidationItemsAxis_CEBA92B2A4D8662B926FFD65C436BD4C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_9E6B6836FC874AEB0499FD65C436840A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_CEBA92B2A4D8662B926FFD65C436BD4C" xlink:to="loc_us-gaap_ConsolidationItemsDomain_9E6B6836FC874AEB0499FD65C436840A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_9E6B6836FC874AEB0499FD65C436840A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_CEBA92B2A4D8662B926FFD65C436BD4C" xlink:to="loc_us-gaap_ConsolidationItemsDomain_9E6B6836FC874AEB0499FD65C436840A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_18D3460670261E2364C5FD65C4366B3F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_9E6B6836FC874AEB0499FD65C436840A" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_18D3460670261E2364C5FD65C4366B3F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_368A8BFEA1241FF38A14FD65C4368861" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedStatementOfComprehensiveIncomeTable_993EBBAAE4ED26F810DAFD65C4367413" xlink:to="loc_dei_LegalEntityAxis_368A8BFEA1241FF38A14FD65C4368861" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_60AFBCE771049C71E5CFFD65C4361BDA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_368A8BFEA1241FF38A14FD65C4368861" xlink:to="loc_dei_EntityDomain_60AFBCE771049C71E5CFFD65C4361BDA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_60AFBCE771049C71E5CFFD65C4361BDA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_368A8BFEA1241FF38A14FD65C4368861" xlink:to="loc_dei_EntityDomain_60AFBCE771049C71E5CFFD65C4361BDA" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldLLCMember" xlink:label="loc_nrg_NRGYieldLLCMember_C12457E320970C377CBAFD65C4374443" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_60AFBCE771049C71E5CFFD65C4361BDA" xlink:to="loc_nrg_NRGYieldLLCMember_C12457E320970C377CBAFD65C4374443" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldOperatingLLCMember" xlink:label="loc_nrg_NRGYieldOperatingLLCMember_BBB77704546CC12ECB3EFD65C437C3C1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_60AFBCE771049C71E5CFFD65C4361BDA" xlink:to="loc_nrg_NRGYieldOperatingLLCMember_BBB77704546CC12ECB3EFD65C437C3C1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_160073CCF5DBFDD53434FD65C4372D0A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedStatementOfComprehensiveIncomeTable_993EBBAAE4ED26F810DAFD65C4367413" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_160073CCF5DBFDD53434FD65C4372D0A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_79418C6752EE69AB9163FD65C437E48D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_160073CCF5DBFDD53434FD65C4372D0A" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_79418C6752EE69AB9163FD65C437E48D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_79418C6752EE69AB9163FD65C437E48D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_160073CCF5DBFDD53434FD65C4372D0A" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_79418C6752EE69AB9163FD65C437E48D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_6CD75D5199F41132EA0CFD65C4379844" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_79418C6752EE69AB9163FD65C437E48D" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_6CD75D5199F41132EA0CFD65C4379844" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_E1686FF2D72215F8503AFD65C4378414" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_79418C6752EE69AB9163FD65C437E48D" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_E1686FF2D72215F8503AFD65C4378414" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_DDC879BCCF6CC39C7762FD65C43713E2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_FA71A545177A6562572EFD65C43756FB" xlink:to="loc_us-gaap_ProfitLoss_DDC879BCCF6CC39C7762FD65C43713E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_32F64BA45425A66EEAB9FD65C4377681" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_FA71A545177A6562572EFD65C43756FB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_32F64BA45425A66EEAB9FD65C4377681" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_D43D7D3F2F20D4D6EE9DFD65C4370D02" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_FA71A545177A6562572EFD65C43756FB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_D43D7D3F2F20D4D6EE9DFD65C4370D02" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_46A938E449A5DE74D48FFD65C4374AA3" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_FA71A545177A6562572EFD65C43756FB" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_46A938E449A5DE74D48FFD65C4374AA3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest_288F863AA8541F1DC6BDFD65C437A843" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_FA71A545177A6562572EFD65C43756FB" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest_288F863AA8541F1DC6BDFD65C437A843" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_7A89FA0B2C6A4085395FFD65C437E9B7" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_FA71A545177A6562572EFD65C43756FB" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_7A89FA0B2C6A4085395FFD65C437E9B7" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/CondensedConsolidatingFinancialInformationPpIncomeStatementDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedIncomeStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedIncomeStatementTable" xlink:label="loc_us-gaap_CondensedIncomeStatementTable_1F481CC7D8DE700D4D580741D67ABDE9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_CondensedIncomeStatementTable_1F481CC7D8DE700D4D580741D67ABDE9" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_6ADD26D8709D6B0E4C8A0741D67AED06" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedIncomeStatementTable_1F481CC7D8DE700D4D580741D67ABDE9" xlink:to="loc_us-gaap_ConsolidationItemsAxis_6ADD26D8709D6B0E4C8A0741D67AED06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_209EDC86EAEE2E1B59F70741D67AA528_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_6ADD26D8709D6B0E4C8A0741D67AED06" xlink:to="loc_us-gaap_ConsolidationItemsDomain_209EDC86EAEE2E1B59F70741D67AA528_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_209EDC86EAEE2E1B59F70741D67AA528" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_6ADD26D8709D6B0E4C8A0741D67AED06" xlink:to="loc_us-gaap_ConsolidationItemsDomain_209EDC86EAEE2E1B59F70741D67AA528" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_633A8CE8CB188F7F7EEF0741D67A9F57" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_209EDC86EAEE2E1B59F70741D67AA528" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_633A8CE8CB188F7F7EEF0741D67A9F57" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_91C4AE24B7AB1B5F0F3B0741D67A02FB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedIncomeStatementTable_1F481CC7D8DE700D4D580741D67ABDE9" xlink:to="loc_dei_LegalEntityAxis_91C4AE24B7AB1B5F0F3B0741D67A02FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_3D4A1CB92926D496C84A0741D67AAD4D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_91C4AE24B7AB1B5F0F3B0741D67A02FB" xlink:to="loc_dei_EntityDomain_3D4A1CB92926D496C84A0741D67AAD4D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_3D4A1CB92926D496C84A0741D67AAD4D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_91C4AE24B7AB1B5F0F3B0741D67A02FB" xlink:to="loc_dei_EntityDomain_3D4A1CB92926D496C84A0741D67AAD4D" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldLLCMember" xlink:label="loc_nrg_NRGYieldLLCMember_AA802296A00BE84DDD8D0741D67A9E80" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_3D4A1CB92926D496C84A0741D67AAD4D" xlink:to="loc_nrg_NRGYieldLLCMember_AA802296A00BE84DDD8D0741D67A9E80" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldOperatingLLCMember" xlink:label="loc_nrg_NRGYieldOperatingLLCMember_9984FC60094B23ED891A0741D67A910A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_3D4A1CB92926D496C84A0741D67AAD4D" xlink:to="loc_nrg_NRGYieldOperatingLLCMember_9984FC60094B23ED891A0741D67A910A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_204F633B75B16270E1520741D67A7A56" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedIncomeStatementTable_1F481CC7D8DE700D4D580741D67ABDE9" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_204F633B75B16270E1520741D67A7A56" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_7D9393E4A04F443A81360741D67AF45D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_204F633B75B16270E1520741D67A7A56" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_7D9393E4A04F443A81360741D67AF45D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_7D9393E4A04F443A81360741D67AF45D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_204F633B75B16270E1520741D67A7A56" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_7D9393E4A04F443A81360741D67AF45D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_E6383FF7904DD08794680741D67A3C4D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_7D9393E4A04F443A81360741D67AF45D" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_E6383FF7904DD08794680741D67A3C4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_BD3D101138BAA38289C50741D67B81BA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_7D9393E4A04F443A81360741D67AF45D" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_BD3D101138BAA38289C50741D67B81BA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_81E82A2DD8BB9D4EBBB40741D67B8CF6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_Revenues_81E82A2DD8BB9D4EBBB40741D67B8CF6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingCostsAndExpensesAbstract" xlink:label="loc_us-gaap_OperatingCostsAndExpensesAbstract_CD5426B0A17E89CEAF8E0741D67B4898" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_OperatingCostsAndExpensesAbstract_CD5426B0A17E89CEAF8E0741D67B4898" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostOfRevenue" xlink:label="loc_us-gaap_CostOfRevenue_FE1686241FF75BA5DA180741D67B44D7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_CostOfRevenue_FE1686241FF75BA5DA180741D67B44D7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_EEFE72BE3046BCB000700741D67BA02E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_EEFE72BE3046BCB000700741D67BA02E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_AC221F94FA541FA1569B0741D67B7EFD" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_AC221F94FA541FA1569B0741D67B7EFD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_50AB6949F753D62F08840741D67B12A9" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_50AB6949F753D62F08840741D67B12A9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostsAndExpenses" xlink:label="loc_us-gaap_CostsAndExpenses_5E3C87710498886AC8A90741D67CFBD7" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_CostsAndExpenses_5E3C87710498886AC8A90741D67CFBD7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_5E10A9571223D0FD0D5A0741D67D8684" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_OperatingIncomeLoss_5E10A9571223D0FD0D5A0741D67D8684" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_EquityInEarningsOfConsolidatedSubsidiaries" xlink:label="loc_nrg_EquityInEarningsOfConsolidatedSubsidiaries_E2D2EE8415147949B9490741D67EE875" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_nrg_EquityInEarningsOfConsolidatedSubsidiaries_E2D2EE8415147949B9490741D67EE875" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_B36F213BE6B0ACC8B3900741D67E2F17" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_B36F213BE6B0ACC8B3900741D67E2F17" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_B696EF859E3E654F5A710741D67E3BEA" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_B696EF859E3E654F5A710741D67E3BEA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_ED2D753DF7B027678EB90741D67E4949" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_ED2D753DF7B027678EB90741D67E4949" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_E326D3275E55287084150741D67ED11E" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_InterestExpense_E326D3275E55287084150741D67ED11E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_A8478686DEA32DC5B73C0741D67E71FA" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_A8478686DEA32DC5B73C0741D67E71FA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_0A720F39E897B41904FE0741D67EFB59" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_ProfitLoss_0A720F39E897B41904FE0741D67EFB59" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_01B99F31B1FF6392192A0741D67E44D3" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_01B99F31B1FF6392192A0741D67E44D3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_00EF0FDDF89032F2B2F40741D67EC56B" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_03B14463D9A689E743A90741D67B8019" xlink:to="loc_us-gaap_NetIncomeLoss_00EF0FDDF89032F2B2F40741D67EC56B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/ConsolidatedBalanceSheets" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_CE28598FC008EE15525F1C5E5A073DD9" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_BC8E82C1BA2B2173A46F1C5E5A06216F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_CE28598FC008EE15525F1C5E5A073DD9" xlink:to="loc_us-gaap_StatementTable_BC8E82C1BA2B2173A46F1C5E5A06216F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_A13A8BE505B282B79FA11C5E5A062DE8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_BC8E82C1BA2B2173A46F1C5E5A06216F" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_A13A8BE505B282B79FA11C5E5A062DE8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_05A176675E1453C804661C5E5A06B90F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_A13A8BE505B282B79FA11C5E5A062DE8" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_05A176675E1453C804661C5E5A06B90F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_05A176675E1453C804661C5E5A06B90F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_A13A8BE505B282B79FA11C5E5A062DE8" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_05A176675E1453C804661C5E5A06B90F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1566B9E5BC7A7846C33F1C5E5A06BF78" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_BC8E82C1BA2B2173A46F1C5E5A06216F" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1566B9E5BC7A7846C33F1C5E5A06BF78" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_192E7D8506D093E0F81B1C5E5A062D23_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1566B9E5BC7A7846C33F1C5E5A06BF78" xlink:to="loc_us-gaap_RelatedPartyDomain_192E7D8506D093E0F81B1C5E5A062D23_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_192E7D8506D093E0F81B1C5E5A062D23" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1566B9E5BC7A7846C33F1C5E5A06BF78" xlink:to="loc_us-gaap_RelatedPartyDomain_192E7D8506D093E0F81B1C5E5A062D23" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_C819807A6C59BFAF0DFA1C5E5A07D6FB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_BC8E82C1BA2B2173A46F1C5E5A06216F" xlink:to="loc_dei_LegalEntityAxis_C819807A6C59BFAF0DFA1C5E5A07D6FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_9F8E71CB748DF1FD4D1F1C5E5A0772DC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_C819807A6C59BFAF0DFA1C5E5A07D6FB" xlink:to="loc_dei_EntityDomain_9F8E71CB748DF1FD4D1F1C5E5A0772DC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_9F8E71CB748DF1FD4D1F1C5E5A0772DC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_C819807A6C59BFAF0DFA1C5E5A07D6FB" xlink:to="loc_dei_EntityDomain_9F8E71CB748DF1FD4D1F1C5E5A0772DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_37BD3F57FEC4A593B3241C5E5A07D2DB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_CE28598FC008EE15525F1C5E5A073DD9" xlink:to="loc_us-gaap_AssetsAbstract_37BD3F57FEC4A593B3241C5E5A07D2DB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract_77100C6E6AFE4F1626B21C5E5A07BAAF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_37BD3F57FEC4A593B3241C5E5A07D2DB" xlink:to="loc_us-gaap_AssetsCurrentAbstract_77100C6E6AFE4F1626B21C5E5A07BAAF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_6AFCC5FDA16A2ACD762A1C5E5A073999" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_77100C6E6AFE4F1626B21C5E5A07BAAF" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_6AFCC5FDA16A2ACD762A1C5E5A073999" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_74067CF65B4CAD46C0CD1C5E5A079595" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_77100C6E6AFE4F1626B21C5E5A07BAAF" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_74067CF65B4CAD46C0CD1C5E5A079595" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_8DC83DB1061DDE6916881C5E5A07632E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_77100C6E6AFE4F1626B21C5E5A07BAAF" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_8DC83DB1061DDE6916881C5E5A07632E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_8AC8B09D838A6D79FD711C5E5A077ACD" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_77100C6E6AFE4F1626B21C5E5A07BAAF" xlink:to="loc_us-gaap_InventoryNet_8AC8B09D838A6D79FD711C5E5A077ACD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NotesAndLoansReceivableNetCurrent" xlink:label="loc_us-gaap_NotesAndLoansReceivableNetCurrent_A538571DE8673FDAEE3F1C5E5A07D58A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_77100C6E6AFE4F1626B21C5E5A07BAAF" xlink:to="loc_us-gaap_NotesAndLoansReceivableNetCurrent_A538571DE8673FDAEE3F1C5E5A07D58A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_6FF520294EA67CE5E25D1C5E5A0807BF" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_77100C6E6AFE4F1626B21C5E5A07BAAF" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_6FF520294EA67CE5E25D1C5E5A0807BF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_7B3C003E43298A9288B41C5E5A082D86" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_77100C6E6AFE4F1626B21C5E5A07BAAF" xlink:to="loc_us-gaap_AssetsCurrent_7B3C003E43298A9288B41C5E5A082D86" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract_BF2AD7BF5CF612289B3F1C5E5A086930" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_37BD3F57FEC4A593B3241C5E5A07D2DB" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAbstract_BF2AD7BF5CF612289B3F1C5E5A086930" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_A08211851B48B00C3CD41C5E5A08CF37" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_BF2AD7BF5CF612289B3F1C5E5A086930" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_A08211851B48B00C3CD41C5E5A08CF37" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsNoncurrentAbstract" xlink:label="loc_us-gaap_AssetsNoncurrentAbstract_737D6EC46E1FAD4608C01C5E5A08E1A9" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_37BD3F57FEC4A593B3241C5E5A07D2DB" xlink:to="loc_us-gaap_AssetsNoncurrentAbstract_737D6EC46E1FAD4608C01C5E5A08E1A9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:label="loc_us-gaap_EquityMethodInvestments_292C0AD9A4FD5ADDA83A1C5E5A08C6F2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_737D6EC46E1FAD4608C01C5E5A08E1A9" xlink:to="loc_us-gaap_EquityMethodInvestments_292C0AD9A4FD5ADDA83A1C5E5A08C6F2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_6CDBAC8D2D5B421C684E1C5E5A08C41F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_737D6EC46E1FAD4608C01C5E5A08E1A9" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_6CDBAC8D2D5B421C684E1C5E5A08C41F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeAssetsNoncurrent" xlink:label="loc_us-gaap_DerivativeAssetsNoncurrent_A79DF1C42077AB88E6DB1C5E5A083B24" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_737D6EC46E1FAD4608C01C5E5A08E1A9" xlink:to="loc_us-gaap_DerivativeAssetsNoncurrent_A79DF1C42077AB88E6DB1C5E5A083B24" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_6770EDCC7C9FFD53D27F1C5E5A0880B5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_737D6EC46E1FAD4608C01C5E5A08E1A9" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_6770EDCC7C9FFD53D27F1C5E5A0880B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssets" xlink:label="loc_us-gaap_OtherAssets_EC0EB245E885F6A87E8A1C5E5A08F08A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_737D6EC46E1FAD4608C01C5E5A08E1A9" xlink:to="loc_us-gaap_OtherAssets_EC0EB245E885F6A87E8A1C5E5A08F08A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_E34C8ACD9F89CBC888121C5E5A09A28E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_37BD3F57FEC4A593B3241C5E5A07D2DB" xlink:to="loc_us-gaap_Assets_E34C8ACD9F89CBC888121C5E5A09A28E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_232C0EF9A752300F31D31C5E5A0975F8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_CE28598FC008EE15525F1C5E5A073DD9" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_232C0EF9A752300F31D31C5E5A0975F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_71042AF1FE1847FDF0771C5E5A09B396" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_232C0EF9A752300F31D31C5E5A0975F8" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_71042AF1FE1847FDF0771C5E5A09B396" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_55569477568E4A3E05221C5E5A09C2FA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_71042AF1FE1847FDF0771C5E5A09B396" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_55569477568E4A3E05221C5E5A09C2FA" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AffiliateCurrentDebt" xlink:label="loc_nrg_AffiliateCurrentDebt_B2C41C70D713FBAF4E6A1C5E5A093166" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_71042AF1FE1847FDF0771C5E5A09B396" xlink:to="loc_nrg_AffiliateCurrentDebt_B2C41C70D713FBAF4E6A1C5E5A093166" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_377FD218C197DEDB5C651C5E5A0967FD" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_71042AF1FE1847FDF0771C5E5A09B396" xlink:to="loc_us-gaap_AccountsPayableCurrent_377FD218C197DEDB5C651C5E5A0967FD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToAffiliateCurrent" xlink:label="loc_us-gaap_DueToAffiliateCurrent_A04E0ACA4CFF25C337411C5E5A09D59D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_71042AF1FE1847FDF0771C5E5A09B396" xlink:to="loc_us-gaap_DueToAffiliateCurrent_A04E0ACA4CFF25C337411C5E5A09D59D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilitiesCurrent" xlink:label="loc_us-gaap_DerivativeLiabilitiesCurrent_324D26261C524753029E1C5E5A091280" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_71042AF1FE1847FDF0771C5E5A09B396" xlink:to="loc_us-gaap_DerivativeLiabilitiesCurrent_324D26261C524753029E1C5E5A091280" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent_8792889459331AEDCD261C5E5A0A090A" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_71042AF1FE1847FDF0771C5E5A09B396" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesCurrent_8792889459331AEDCD261C5E5A0A090A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_CA3D657B27EED33F24611C5E5A0A2395" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_71042AF1FE1847FDF0771C5E5A09B396" xlink:to="loc_us-gaap_LiabilitiesCurrent_CA3D657B27EED33F24611C5E5A0A2395" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesNoncurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesNoncurrentAbstract_3B5CE5027EC383BB19351C5E5A0A26DC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_232C0EF9A752300F31D31C5E5A0975F8" xlink:to="loc_us-gaap_LiabilitiesNoncurrentAbstract_3B5CE5027EC383BB19351C5E5A0A26DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligations" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_3ED8C8B1150028FEE26C1C5E5A0AF984" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_3B5CE5027EC383BB19351C5E5A0A26DC" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_3ED8C8B1150028FEE26C1C5E5A0AF984" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToAffiliateNoncurrent" xlink:label="loc_us-gaap_DueToAffiliateNoncurrent_45FF3B6532D30B3E78641C5E5A0A7EE7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_3B5CE5027EC383BB19351C5E5A0A26DC" xlink:to="loc_us-gaap_DueToAffiliateNoncurrent_45FF3B6532D30B3E78641C5E5A0A7EE7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilitiesNoncurrent" xlink:label="loc_us-gaap_DerivativeLiabilitiesNoncurrent_04E943D5BB70DF6DC5F21C5E5A0A5373" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_3B5CE5027EC383BB19351C5E5A0A26DC" xlink:to="loc_us-gaap_DerivativeLiabilitiesNoncurrent_04E943D5BB70DF6DC5F21C5E5A0A5373" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_B8365C82FDCCA71710171C5E5A0A5A6B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_3B5CE5027EC383BB19351C5E5A0A26DC" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_B8365C82FDCCA71710171C5E5A0A5A6B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesNoncurrent" xlink:label="loc_us-gaap_LiabilitiesNoncurrent_EDB6EA6D35A0282578971C5E5A0A4B26" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_3B5CE5027EC383BB19351C5E5A0A26DC" xlink:to="loc_us-gaap_LiabilitiesNoncurrent_EDB6EA6D35A0282578971C5E5A0A4B26" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_D4E441F0901A45D892FF1C5E5A0B326D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_232C0EF9A752300F31D31C5E5A0975F8" xlink:to="loc_us-gaap_Liabilities_D4E441F0901A45D892FF1C5E5A0B326D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_C112083A7270EE65B5201C5E5A0BD556" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_232C0EF9A752300F31D31C5E5A0975F8" xlink:to="loc_us-gaap_CommitmentsAndContingencies_C112083A7270EE65B5201C5E5A0BD556" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="loc_us-gaap_StockholdersEquityAbstract_680D0C57F583455D90861C5E5A0BFC64" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_232C0EF9A752300F31D31C5E5A0975F8" xlink:to="loc_us-gaap_StockholdersEquityAbstract_680D0C57F583455D90861C5E5A0BFC64" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MembersCapital" xlink:label="loc_us-gaap_MembersCapital_39EF91A6C4986B3B9D1D1C5E5A0B5C76" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_680D0C57F583455D90861C5E5A0BFC64" xlink:to="loc_us-gaap_MembersCapital_39EF91A6C4986B3B9D1D1C5E5A0B5C76" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_36514093F3B3C52F11561C5E5A0BF04F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_680D0C57F583455D90861C5E5A0BFC64" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_36514093F3B3C52F11561C5E5A0BF04F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_47D08231670BAF8075D41C5E5A0BCA65" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_680D0C57F583455D90861C5E5A0BFC64" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_47D08231670BAF8075D41C5E5A0BCA65" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MembersEquityAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_MembersEquityAttributableToNoncontrollingInterest_3E89D427624431DFBF901C5E5A0B7046" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_680D0C57F583455D90861C5E5A0BFC64" xlink:to="loc_us-gaap_MembersEquityAttributableToNoncontrollingInterest_3E89D427624431DFBF901C5E5A0B7046" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MembersEquity" xlink:label="loc_us-gaap_MembersEquity_A66FB46159C9F3B5B29B1C5E5A0B4990" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_680D0C57F583455D90861C5E5A0BFC64" xlink:to="loc_us-gaap_MembersEquity_A66FB46159C9F3B5B29B1C5E5A0B4990" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_A2A6D5AADD999D5BB3601C5E5A0B5D4D" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_232C0EF9A752300F31D31C5E5A0975F8" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_A2A6D5AADD999D5BB3601C5E5A0B5D4D" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_B1A8A8C070F815DDEF530741D8FF1ED6" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_5A4E29E93F19D0B958590741D8FE81B6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_B1A8A8C070F815DDEF530741D8FF1ED6" xlink:to="loc_us-gaap_StatementTable_5A4E29E93F19D0B958590741D8FE81B6" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_8019DC3C866E0616AA550741D8FFCF7E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_5A4E29E93F19D0B958590741D8FE81B6" xlink:to="loc_us-gaap_StatementScenarioAxis_8019DC3C866E0616AA550741D8FFCF7E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_454D8D2FE0B2D2797BB40741D8FF94AA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_8019DC3C866E0616AA550741D8FFCF7E" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_454D8D2FE0B2D2797BB40741D8FF94AA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_454D8D2FE0B2D2797BB40741D8FF94AA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_8019DC3C866E0616AA550741D8FFCF7E" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_454D8D2FE0B2D2797BB40741D8FF94AA" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/DocumentAndEntityInformation" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockLineItems" xlink:label="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_BCBBCB86488669F9FB1B17771AEAEFFD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_BCBBCB86488669F9FB1B17771AEAEFFD" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_90DDAF96084A276D0A1817771AEA21D7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_BCBBCB86488669F9FB1B17771AEAEFFD" xlink:to="loc_us-gaap_StatementClassOfStockAxis_90DDAF96084A276D0A1817771AEA21D7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_0F8E4CBBEF5D34C036FD17771AEA8332_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_90DDAF96084A276D0A1817771AEA21D7" xlink:to="loc_us-gaap_ClassOfStockDomain_0F8E4CBBEF5D34C036FD17771AEA8332_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_0F8E4CBBEF5D34C036FD17771AEA8332" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_90DDAF96084A276D0A1817771AEA21D7" xlink:to="loc_us-gaap_ClassOfStockDomain_0F8E4CBBEF5D34C036FD17771AEA8332" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember_D04C270C61316FCA92D417771AEAF8F4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_0F8E4CBBEF5D34C036FD17771AEA8332" xlink:to="loc_us-gaap_CommonClassAMember_D04C270C61316FCA92D417771AEAF8F4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonClassBMember" xlink:label="loc_us-gaap_CommonClassBMember_C379ADEAAC9CCEE44FDE17771AEA1DE0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_0F8E4CBBEF5D34C036FD17771AEA8332" xlink:to="loc_us-gaap_CommonClassBMember_C379ADEAAC9CCEE44FDE17771AEA1DE0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonClassCMember" xlink:label="loc_us-gaap_CommonClassCMember_023AA958568B42B64D2E17771AEA090C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_0F8E4CBBEF5D34C036FD17771AEA8332" xlink:to="loc_us-gaap_CommonClassCMember_023AA958568B42B64D2E17771AEA090C" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CommonClassDMember" xlink:label="loc_nrg_CommonClassDMember_5F9452CCED84169ACDA917771AEA8CB0" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_0F8E4CBBEF5D34C036FD17771AEA8332" xlink:to="loc_nrg_CommonClassDMember_5F9452CCED84169ACDA917771AEA8CB0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityRegistrantName" xlink:label="loc_dei_EntityRegistrantName_595EF8956ABF0059B7B317771AEBFB1E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:to="loc_dei_EntityRegistrantName_595EF8956ABF0059B7B317771AEBFB1E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCentralIndexKey" xlink:label="loc_dei_EntityCentralIndexKey_AAD0C9CF37CF8BD4F63817771AEBDD4E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:to="loc_dei_EntityCentralIndexKey_AAD0C9CF37CF8BD4F63817771AEBDD4E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentType" xlink:label="loc_dei_DocumentType_959F9B2A91BD62B901A517771AF047AD" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:to="loc_dei_DocumentType_959F9B2A91BD62B901A517771AF047AD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_350589DA0EA15E4A607417771AF046BD" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:to="loc_dei_DocumentPeriodEndDate_350589DA0EA15E4A607417771AF046BD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_AmendmentFlag" xlink:label="loc_dei_AmendmentFlag_CDEA6FF73E780452E71C17771AF04167" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:to="loc_dei_AmendmentFlag_CDEA6FF73E780452E71C17771AF04167" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_CurrentFiscalYearEndDate" xlink:label="loc_dei_CurrentFiscalYearEndDate_F86CBF7DCEAE5EECCD1717771AF0D94F" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:to="loc_dei_CurrentFiscalYearEndDate_F86CBF7DCEAE5EECCD1717771AF0D94F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCurrentReportingStatus" xlink:label="loc_dei_EntityCurrentReportingStatus_01EEAE4E44213C0F425F17771AF166C4" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:to="loc_dei_EntityCurrentReportingStatus_01EEAE4E44213C0F425F17771AF166C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityFilerCategory" xlink:label="loc_dei_EntityFilerCategory_A97FB947847DB4C1D7BE17771AF16846" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:to="loc_dei_EntityFilerCategory_A97FB947847DB4C1D7BE17771AF16846" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityVoluntaryFilers" xlink:label="loc_dei_EntityVoluntaryFilers_4CAB1EC2A64B0CCD681C17771AF13022" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:to="loc_dei_EntityVoluntaryFilers_4CAB1EC2A64B0CCD681C17771AF13022" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityWellKnownSeasonedIssuer" xlink:label="loc_dei_EntityWellKnownSeasonedIssuer_4B740B6C2B6E47710FB717771AF123B1" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:to="loc_dei_EntityWellKnownSeasonedIssuer_4B740B6C2B6E47710FB717771AF123B1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentFiscalYearFocus" xlink:label="loc_dei_DocumentFiscalYearFocus_264143483A48CC095B1117771AF16414" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:to="loc_dei_DocumentFiscalYearFocus_264143483A48CC095B1117771AF16414" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="loc_dei_DocumentFiscalPeriodFocus_F2696C4F7DDDFA2BC3AF17771AF19530" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:to="loc_dei_DocumentFiscalPeriodFocus_F2696C4F7DDDFA2BC3AF17771AF19530" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_42ADCD974762432EE49217771AF1F960" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_86DA1F7738CEA524AF6817771AEB4BFD" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_42ADCD974762432EE49217771AF1F960" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/FairValueOfFinancialInstruments" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/FairValueOfFinancialInstrumentsFairValueOfFinancialInstrumentsBalanceSheetGroupingDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_5824FE62C96E01A6EDBFFD65C4F36730" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6DBEFFE6723150D0DCF5FD65C4F35B6F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_5824FE62C96E01A6EDBFFD65C4F36730" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6DBEFFE6723150D0DCF5FD65C4F35B6F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_353F46DB9425A5B7CA2FFD65C4F3D476" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6DBEFFE6723150D0DCF5FD65C4F35B6F" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_353F46DB9425A5B7CA2FFD65C4F3D476" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_CF118035DE3EA0D341A5FD65C4F3087B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_353F46DB9425A5B7CA2FFD65C4F3D476" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_CF118035DE3EA0D341A5FD65C4F3087B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_037F4FE0FC6D34781D63FD65C4F3BBA3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_353F46DB9425A5B7CA2FFD65C4F3D476" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_037F4FE0FC6D34781D63FD65C4F3BBA3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_CF118035DE3EA0D341A5FD65C4F3087B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_037F4FE0FC6D34781D63FD65C4F3BBA3" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_CF118035DE3EA0D341A5FD65C4F3087B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_1EAAE09490DA61D4233FFD65C4F3847C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_037F4FE0FC6D34781D63FD65C4F3BBA3" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_1EAAE09490DA61D4233FFD65C4F3847C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_342434379071BE84C78DFD65C4F3DDB6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_037F4FE0FC6D34781D63FD65C4F3BBA3" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_342434379071BE84C78DFD65C4F3DDB6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_DEB67BB621B6DBDAD8BEFD65C4F3920F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6DBEFFE6723150D0DCF5FD65C4F35B6F" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_DEB67BB621B6DBDAD8BEFD65C4F3920F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_D6D4D1419C0B9D724F3FFD65C4F3D853_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_DEB67BB621B6DBDAD8BEFD65C4F3920F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_D6D4D1419C0B9D724F3FFD65C4F3D853_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_D6D4D1419C0B9D724F3FFD65C4F3D853" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_DEB67BB621B6DBDAD8BEFD65C4F3920F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_D6D4D1419C0B9D724F3FFD65C4F3D853" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_FDF96EB72D3FF92B7269FD65C4F367DE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_D6D4D1419C0B9D724F3FFD65C4F3D853" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_FDF96EB72D3FF92B7269FD65C4F367DE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_C7334C7391BE891FDE23FD65C4F37A1C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_D6D4D1419C0B9D724F3FFD65C4F3D853" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_C7334C7391BE891FDE23FD65C4F37A1C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NotesReceivableNet" xlink:label="loc_us-gaap_NotesReceivableNet_E5E87ABF08EC3AC71D8FFD65C4F376FE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_5824FE62C96E01A6EDBFFD65C4F36730" xlink:to="loc_us-gaap_NotesReceivableNet_E5E87ABF08EC3AC71D8FFD65C4F376FE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToAffiliateNoncurrent" xlink:label="loc_us-gaap_DueToAffiliateNoncurrent_06846EC4DA5494E70265FD65C4F3ED24" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_5824FE62C96E01A6EDBFFD65C4F36730" xlink:to="loc_us-gaap_DueToAffiliateNoncurrent_06846EC4DA5494E70265FD65C4F3ED24" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities_A7D6A3C34E682433BBC6FD65C4F369EA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_5824FE62C96E01A6EDBFFD65C4F36730" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities_A7D6A3C34E682433BBC6FD65C4F369EA" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/FairValueOfFinancialInstrumentsFairValueOfFinancialInstrumentsCreditRiskAndDerivativeFvMeasurementsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_5CD073E43F67E64644CCFD65C4EAD564" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_49A5109FD8A75990ED48FD65C4E94BB2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_5CD073E43F67E64644CCFD65C4EAD564" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_49A5109FD8A75990ED48FD65C4E94BB2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_098702FDB0E6268BCBF1FD65C4E96331" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_49A5109FD8A75990ED48FD65C4E94BB2" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_098702FDB0E6268BCBF1FD65C4E96331" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_0E23B2BA1334DFB98A7BFD65C4E9262E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_098702FDB0E6268BCBF1FD65C4E96331" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_0E23B2BA1334DFB98A7BFD65C4E9262E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_0E23B2BA1334DFB98A7BFD65C4E9262E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_098702FDB0E6268BCBF1FD65C4E96331" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_0E23B2BA1334DFB98A7BFD65C4E9262E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestExpenseMember" xlink:label="loc_us-gaap_InterestExpenseMember_BD859AE8FBD74FB26CA5FD65C4E90F08" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_0E23B2BA1334DFB98A7BFD65C4E9262E" xlink:to="loc_us-gaap_InterestExpenseMember_BD859AE8FBD74FB26CA5FD65C4E90F08" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLocationAxis" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLocationAxis_DBA61C184CADAAEA2A9DFD65C4E93191" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_49A5109FD8A75990ED48FD65C4E94BB2" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLocationAxis_DBA61C184CADAAEA2A9DFD65C4E93191" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLocationDomain" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLocationDomain_AA6FFF454C1576BC2B86FD65C4E91833_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLocationAxis_DBA61C184CADAAEA2A9DFD65C4E93191" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLocationDomain_AA6FFF454C1576BC2B86FD65C4E91833_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLocationDomain" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLocationDomain_AA6FFF454C1576BC2B86FD65C4E91833" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLocationAxis_DBA61C184CADAAEA2A9DFD65C4E93191" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLocationDomain_AA6FFF454C1576BC2B86FD65C4E91833" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_FairValueAssetsMeasuredOnRecurringBasisValuationTechniquesImpactOfCreditReserveToFairValue" xlink:label="loc_nrg_FairValueAssetsMeasuredOnRecurringBasisValuationTechniquesImpactOfCreditReserveToFairValue_1FC31CC6CC31D6C3714CFD65C4EAFB61" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_5CD073E43F67E64644CCFD65C4EAD564" xlink:to="loc_nrg_FairValueAssetsMeasuredOnRecurringBasisValuationTechniquesImpactOfCreditReserveToFairValue_1FC31CC6CC31D6C3714CFD65C4EAFB61" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure" xlink:label="loc_us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure_2666FA82AD89DD637661FD65C4EAA76F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_5CD073E43F67E64644CCFD65C4EAD564" xlink:to="loc_us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure_2666FA82AD89DD637661FD65C4EAA76F" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_EstimatedCounterpartyCreditRiskExposureToCertainCounterpartiesPeriod" xlink:label="loc_nrg_EstimatedCounterpartyCreditRiskExposureToCertainCounterpartiesPeriod_1C5A4141A0E1FA221959FD65C4EA8348" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_5CD073E43F67E64644CCFD65C4EAD564" xlink:to="loc_nrg_EstimatedCounterpartyCreditRiskExposureToCertainCounterpartiesPeriod_1C5A4141A0E1FA221959FD65C4EA8348" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/FairValueOfFinancialInstrumentsFairValueOfFinancialInstrumentsRecurringFairValueDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_A0D19B145B25240DB9F51873B1A50029" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_474D440F1B73C61CA7481873B19E02BF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_A0D19B145B25240DB9F51873B1A50029" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_474D440F1B73C61CA7481873B19E02BF" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_9505D630A3FAF9A8803E1873B19E1F90" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_474D440F1B73C61CA7481873B19E02BF" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_9505D630A3FAF9A8803E1873B19E1F90" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_99BD74436EBBEAA8D0391873B19F90CE_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_9505D630A3FAF9A8803E1873B19E1F90" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_99BD74436EBBEAA8D0391873B19F90CE_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_99BD74436EBBEAA8D0391873B19F90CE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_9505D630A3FAF9A8803E1873B19E1F90" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_99BD74436EBBEAA8D0391873B19F90CE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestRateContractMember" xlink:label="loc_us-gaap_InterestRateContractMember_0190F06C74D8927B25681873B19FFBC2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_99BD74436EBBEAA8D0391873B19F90CE" xlink:to="loc_us-gaap_InterestRateContractMember_0190F06C74D8927B25681873B19FFBC2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommodityContractMember" xlink:label="loc_us-gaap_CommodityContractMember_70441E98607353804EDC1873B1A46BB7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_99BD74436EBBEAA8D0391873B19F90CE" xlink:to="loc_us-gaap_CommodityContractMember_70441E98607353804EDC1873B1A46BB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_592C565608E6D67F9CCC1873B1A4CAF9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_474D440F1B73C61CA7481873B19E02BF" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_592C565608E6D67F9CCC1873B1A4CAF9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_E854AF0AE60B656867EC1873B1A4B14C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_592C565608E6D67F9CCC1873B1A4CAF9" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_E854AF0AE60B656867EC1873B1A4B14C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_E854AF0AE60B656867EC1873B1A4B14C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_592C565608E6D67F9CCC1873B1A4CAF9" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_E854AF0AE60B656867EC1873B1A4B14C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_4FFDFAA424423BC3D7C41873B1A4CF79" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_E854AF0AE60B656867EC1873B1A4B14C" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_4FFDFAA424423BC3D7C41873B1A4CF79" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_25DBAD0561A3D08D8DB41873B1A4254C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_474D440F1B73C61CA7481873B19E02BF" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_25DBAD0561A3D08D8DB41873B1A4254C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4E572B3F9DF01ADB1E801873B1A563F0_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_25DBAD0561A3D08D8DB41873B1A4254C" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4E572B3F9DF01ADB1E801873B1A563F0_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4E572B3F9DF01ADB1E801873B1A563F0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_25DBAD0561A3D08D8DB41873B1A4254C" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4E572B3F9DF01ADB1E801873B1A563F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_B87B6BD2CA9FD4F7B6661873B1A5B3E6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4E572B3F9DF01ADB1E801873B1A563F0" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_B87B6BD2CA9FD4F7B6661873B1A5B3E6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_3228C24B6D5BB043440D1873B1A5F9FC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4E572B3F9DF01ADB1E801873B1A563F0" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_3228C24B6D5BB043440D1873B1A5F9FC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_A04223E2432F619AD91A1873B1A590AC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_A0D19B145B25240DB9F51873B1A50029" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_A04223E2432F619AD91A1873B1A590AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet" xlink:label="loc_us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet_457D190FB55D14035DA81873B1A53604" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_A0D19B145B25240DB9F51873B1A50029" xlink:to="loc_us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet_457D190FB55D14035DA81873B1A53604" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_C919937E1418E910D9351873B1A5D345" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_A0D19B145B25240DB9F51873B1A50029" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_C919937E1418E910D9351873B1A5D345" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_FairValueAssetsMeasuredOnRecurringBasisValuationTechniquesImpactOfCreditReserveToFairValue" xlink:label="loc_nrg_FairValueAssetsMeasuredOnRecurringBasisValuationTechniquesImpactOfCreditReserveToFairValue_4C77B62B460C13D96E441873B1A53371" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_A0D19B145B25240DB9F51873B1A50029" xlink:to="loc_nrg_FairValueAssetsMeasuredOnRecurringBasisValuationTechniquesImpactOfCreditReserveToFairValue_4C77B62B460C13D96E441873B1A53371" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/FairValueOfFinancialInstrumentsTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_E2197944734E8813B36C1873B17FAD2E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_BAC9E1C5584439DEC93C1873B17EC7F1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_E2197944734E8813B36C1873B17FAD2E" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_BAC9E1C5584439DEC93C1873B17EC7F1" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_F86F54028B325D48D50A1873B17F1162" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_BAC9E1C5584439DEC93C1873B17EC7F1" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_F86F54028B325D48D50A1873B17F1162" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_0DA6D284B2E1F48A09641873B17FF494_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_F86F54028B325D48D50A1873B17F1162" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_0DA6D284B2E1F48A09641873B17FF494_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_0DA6D284B2E1F48A09641873B17FF494" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_F86F54028B325D48D50A1873B17F1162" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_0DA6D284B2E1F48A09641873B17FF494" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_50AC7D9DF40A7BA368561873B17FBAA2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_BAC9E1C5584439DEC93C1873B17EC7F1" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_50AC7D9DF40A7BA368561873B17FBAA2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7F8AEA14D4730510A4351873B17FBF51_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_50AC7D9DF40A7BA368561873B17FBAA2" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7F8AEA14D4730510A4351873B17FBF51_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7F8AEA14D4730510A4351873B17FBF51" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_50AC7D9DF40A7BA368561873B17FBAA2" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7F8AEA14D4730510A4351873B17FBF51" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/LongTermDebt" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/LongTermDebtLongTermDebtDebtDisclosuresDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_B69AEC59E65BA05B5A801D033D2B3353" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_B85FD4BB8FA92AE1CF5E1D033D29EA2C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_B69AEC59E65BA05B5A801D033D2B3353" xlink:to="loc_us-gaap_DebtInstrumentTable_B85FD4BB8FA92AE1CF5E1D033D29EA2C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_95E60194A5FE95C29BA91D92BFEEB69A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_B85FD4BB8FA92AE1CF5E1D033D29EA2C" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_95E60194A5FE95C29BA91D92BFEEB69A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_6D433B0BC5337AC9575C1D92C0B6667F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_95E60194A5FE95C29BA91D92BFEEB69A" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_6D433B0BC5337AC9575C1D92C0B6667F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_6D433B0BC5337AC9575C1D92C0B6667F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_95E60194A5FE95C29BA91D92BFEEB69A" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_6D433B0BC5337AC9575C1D92C0B6667F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_2227CD2F1D307EACF8A61D92C00EE2A3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_6D433B0BC5337AC9575C1D92C0B6667F" xlink:to="loc_us-gaap_SubsequentEventMember_2227CD2F1D307EACF8A61D92C00EE2A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_83EC0B9A177A78B243DD1D033D2AD0C0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_B85FD4BB8FA92AE1CF5E1D033D29EA2C" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_83EC0B9A177A78B243DD1D033D2AD0C0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6E37724A80981E9C3E6F1D033D2A2774_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_83EC0B9A177A78B243DD1D033D2AD0C0" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6E37724A80981E9C3E6F1D033D2A2774_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6E37724A80981E9C3E6F1D033D2A2774" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_83EC0B9A177A78B243DD1D033D2AD0C0" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6E37724A80981E9C3E6F1D033D2A2774" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BuckthornSolarDropDownAssetMember" xlink:label="loc_nrg_BuckthornSolarDropDownAssetMember_253D98DA2B384A9898E91D033D2A3F73" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6E37724A80981E9C3E6F1D033D2A2774" xlink:to="loc_nrg_BuckthornSolarDropDownAssetMember_253D98DA2B384A9898E91D033D2A3F73" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_08C8C40BEFA4E59234181D033D2AF18E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_B85FD4BB8FA92AE1CF5E1D033D29EA2C" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_08C8C40BEFA4E59234181D033D2AF18E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_5160A31A68867D0592CE1D033D2A94C1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_08C8C40BEFA4E59234181D033D2AF18E" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_5160A31A68867D0592CE1D033D2A94C1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_5160A31A68867D0592CE1D033D2A94C1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_08C8C40BEFA4E59234181D033D2AF18E" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_5160A31A68867D0592CE1D033D2A94C1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LetterOfCreditMember" xlink:label="loc_us-gaap_LetterOfCreditMember_96AE93D4592B4BD776321D033D2A1D6F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_5160A31A68867D0592CE1D033D2A94C1" xlink:to="loc_us-gaap_LetterOfCreditMember_96AE93D4592B4BD776321D033D2A1D6F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_C332CF46FF00E58855921D033D2B6803" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_B85FD4BB8FA92AE1CF5E1D033D29EA2C" xlink:to="loc_us-gaap_DebtInstrumentAxis_C332CF46FF00E58855921D033D2B6803" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_6EE2067A1A9864F451B91D033D2B1AEA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_C332CF46FF00E58855921D033D2B6803" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_6EE2067A1A9864F451B91D033D2B1AEA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_6EE2067A1A9864F451B91D033D2B1AEA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_C332CF46FF00E58855921D033D2B6803" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_6EE2067A1A9864F451B91D033D2B1AEA" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldRevolvingCreditFacilityMember" xlink:label="loc_nrg_NRGYieldRevolvingCreditFacilityMember_3211CB2DEA51E99C4BBA1D033D2B31D4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6EE2067A1A9864F451B91D033D2B1AEA" xlink:to="loc_nrg_NRGYieldRevolvingCreditFacilityMember_3211CB2DEA51E99C4BBA1D033D2B31D4" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_UtahSolarPortfoliodue2022Member" xlink:label="loc_nrg_UtahSolarPortfoliodue2022Member_EBF82B0B8DE2EBD07CB21D033D2B6740" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6EE2067A1A9864F451B91D033D2B1AEA" xlink:to="loc_nrg_UtahSolarPortfoliodue2022Member_EBF82B0B8DE2EBD07CB21D033D2B6740" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AguaCalienteBorrower2Member" xlink:label="loc_nrg_AguaCalienteBorrower2Member_21898B8FA2698F8429361D033D2B5CB6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6EE2067A1A9864F451B91D033D2B1AEA" xlink:to="loc_nrg_AguaCalienteBorrower2Member_21898B8FA2698F8429361D033D2B5CB6" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BuckthornSolarDropDownAssetMember" xlink:label="loc_nrg_BuckthornSolarDropDownAssetMember_0070708AE8AB2E690CA71D033D2B0F26" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6EE2067A1A9864F451B91D033D2B1AEA" xlink:to="loc_nrg_BuckthornSolarDropDownAssetMember_0070708AE8AB2E690CA71D033D2B0F26" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeNonmonetaryNotionalAmountPercentOfRequiredNeedCoverage" xlink:label="loc_us-gaap_DerivativeNonmonetaryNotionalAmountPercentOfRequiredNeedCoverage_559D1ECBFB8EBF17AE081D033D2B8942" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_B69AEC59E65BA05B5A801D033D2B3353" xlink:to="loc_us-gaap_DerivativeNonmonetaryNotionalAmountPercentOfRequiredNeedCoverage_559D1ECBFB8EBF17AE081D033D2B8942" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityFairValueOfAmountOutstanding" xlink:label="loc_us-gaap_LineOfCreditFacilityFairValueOfAmountOutstanding_8668231A55786A884A5F1D033D2C18FF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_B69AEC59E65BA05B5A801D033D2B3353" xlink:to="loc_us-gaap_LineOfCreditFacilityFairValueOfAmountOutstanding_8668231A55786A884A5F1D033D2C18FF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_7A24C9E5B456DBADF3D51D033D2C8A79" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_B69AEC59E65BA05B5A801D033D2B3353" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_7A24C9E5B456DBADF3D51D033D2C8A79" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_7E5C5AF07791665B43EB1D033D2C46CD" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_B69AEC59E65BA05B5A801D033D2B3353" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_7E5C5AF07791665B43EB1D033D2C46CD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_1401959C6713ACBAC7CB1D033D2C4BB9" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_B69AEC59E65BA05B5A801D033D2B3353" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_1401959C6713ACBAC7CB1D033D2C4BB9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_C75AF8E5913BC0A1E0A21D033D2C7976" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_B69AEC59E65BA05B5A801D033D2B3353" xlink:to="loc_us-gaap_LongTermDebt_C75AF8E5913BC0A1E0A21D033D2C7976" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_BFD6F333B3F43CC238A61D033D2C4652" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_B69AEC59E65BA05B5A801D033D2B3353" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_BFD6F333B3F43CC238A61D033D2C4652" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfDebt" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfDebt_838A83A900D40D907A1C1D033D2C484A" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_B69AEC59E65BA05B5A801D033D2B3353" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfDebt_838A83A900D40D907A1C1D033D2C484A" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/LongTermDebtLongTermDebtDebtTableDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_45BA2B77D0D23BAE48A81C5E585C09A1" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_BD811BAFAC679097A6D61C5E58589A03" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_45BA2B77D0D23BAE48A81C5E585C09A1" xlink:to="loc_us-gaap_DebtInstrumentTable_BD811BAFAC679097A6D61C5E58589A03" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_DC806D063A93ED5244C21C5E5858D7E4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_BD811BAFAC679097A6D61C5E58589A03" xlink:to="loc_us-gaap_RangeAxis_DC806D063A93ED5244C21C5E5858D7E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_65F095196ADC6978642F1C5E5858F8AF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_DC806D063A93ED5244C21C5E5858D7E4" xlink:to="loc_us-gaap_RangeMember_65F095196ADC6978642F1C5E5858F8AF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_65F095196ADC6978642F1C5E5858F8AF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_DC806D063A93ED5244C21C5E5858D7E4" xlink:to="loc_us-gaap_RangeMember_65F095196ADC6978642F1C5E5858F8AF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_2E86F30887C8FD50B0001C5E5859E0B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_65F095196ADC6978642F1C5E5858F8AF" xlink:to="loc_us-gaap_MinimumMember_2E86F30887C8FD50B0001C5E5859E0B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_9797F6255DAB2BF6AFA01C5E5859DBA9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_65F095196ADC6978642F1C5E5858F8AF" xlink:to="loc_us-gaap_MaximumMember_9797F6255DAB2BF6AFA01C5E5859DBA9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_64970DA121C6353BF6211C5E58596E0B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_BD811BAFAC679097A6D61C5E58589A03" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_64970DA121C6353BF6211C5E58596E0B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_E685B919D4693D428B761C5E5859FEAB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_64970DA121C6353BF6211C5E58596E0B" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_E685B919D4693D428B761C5E5859FEAB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_E685B919D4693D428B761C5E5859FEAB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_64970DA121C6353BF6211C5E58596E0B" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_E685B919D4693D428B761C5E5859FEAB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LetterOfCreditMember" xlink:label="loc_us-gaap_LetterOfCreditMember_749093A45AF8DB774C541C5E5859C7AD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_E685B919D4693D428B761C5E5859FEAB" xlink:to="loc_us-gaap_LetterOfCreditMember_749093A45AF8DB774C541C5E5859C7AD" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ExternalandAffiliateDebtMember" xlink:label="loc_nrg_ExternalandAffiliateDebtMember_B828AE36B6D8D6AED69D1C5E5859AE99" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_E685B919D4693D428B761C5E5859FEAB" xlink:to="loc_nrg_ExternalandAffiliateDebtMember_B828AE36B6D8D6AED69D1C5E5859AE99" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_7D034AE0F105351E7DF41C5E58592AC2" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_BD811BAFAC679097A6D61C5E58589A03" xlink:to="loc_us-gaap_DebtInstrumentAxis_7D034AE0F105351E7DF41C5E58592AC2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_7D034AE0F105351E7DF41C5E58592AC2" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_7D034AE0F105351E7DF41C5E58592AC2" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BuckthornSolarDropDownAssetMember" xlink:label="loc_nrg_BuckthornSolarDropDownAssetMember_2C699EDDAE7E9937C4E81C5E5859F538" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_BuckthornSolarDropDownAssetMember_2C699EDDAE7E9937C4E81C5E5859F538" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_A5.375SeniorNotesduein2024Member" xlink:label="loc_nrg_A5.375SeniorNotesduein2024Member_F414E16A1D9B0A2404731C5E585A59D5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_A5.375SeniorNotesduein2024Member_F414E16A1D9B0A2404731C5E585A59D5" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_A5.00SeniorNotesduein2026Member" xlink:label="loc_nrg_A5.00SeniorNotesduein2026Member_DC367CF9889EECB1BB221C5E585A1FF7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_A5.00SeniorNotesduein2026Member_DC367CF9889EECB1BB221C5E585A1FF7" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AguaCalienteBorrower2Member" xlink:label="loc_nrg_AguaCalienteBorrower2Member_C0DA0B533EB8559B166B1C5E585AE922" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_AguaCalienteBorrower2Member_C0DA0B533EB8559B166B1C5E585AE922" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_IntercompanyCreditAgreementdue2019Member" xlink:label="loc_nrg_IntercompanyCreditAgreementdue2019Member_55541EBBB6D42D1B55631C5E585AA4B9" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_IntercompanyCreditAgreementdue2019Member_55541EBBB6D42D1B55631C5E585AA4B9" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_IntercompanyCreditAgreementdue2020Member" xlink:label="loc_nrg_IntercompanyCreditAgreementdue2020Member_F45CB2A5C41156730A971C5E585A0BC8" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_IntercompanyCreditAgreementdue2020Member_F45CB2A5C41156730A971C5E585A0BC8" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldRevolvingCreditFacilityMember" xlink:label="loc_nrg_NRGYieldRevolvingCreditFacilityMember_321EDEDE0EFAB421820F1C5E585A4CC8" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_NRGYieldRevolvingCreditFacilityMember_321EDEDE0EFAB421820F1C5E585A4CC8" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_WestHoldingsCreditAgreementMember" xlink:label="loc_nrg_WestHoldingsCreditAgreementMember_97135099B152F56095421C5E585AC601" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_WestHoldingsCreditAgreementMember_97135099B152F56095421C5E585AC601" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_WestHoldingsCreditAgreementdue2023TrancheAMember" xlink:label="loc_nrg_WestHoldingsCreditAgreementdue2023TrancheAMember_1539A4D9475ADEE0C0E21C5E585ACEA8" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_WestHoldingsCreditAgreementdue2023TrancheAMember_1539A4D9475ADEE0C0E21C5E585ACEA8" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_MarshLandingTermLoanFacilityMember" xlink:label="loc_nrg_MarshLandingTermLoanFacilityMember_C7A8E20BBF189875F4531C5E585A61A7" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_MarshLandingTermLoanFacilityMember_C7A8E20BBF189875F4531C5E585A61A7" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_MarshLandingMember" xlink:label="loc_nrg_MarshLandingMember_37A264BB6DAECB249F2D1C5E585ACA1A" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_MarshLandingMember_37A264BB6DAECB249F2D1C5E585ACA1A" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_WalnutCreekEnergyLLCduein2023Member" xlink:label="loc_nrg_WalnutCreekEnergyLLCduein2023Member_C64663F4F26ACB6EFC391C5E585A4139" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_WalnutCreekEnergyLLCduein2023Member_C64663F4F26ACB6EFC391C5E585A4139" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_TapestryWindLLCduein2021Member" xlink:label="loc_nrg_TapestryWindLLCduein2021Member_E3F30804BDC4EF86B5691C5E585A0301" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_TapestryWindLLCduein2021Member_E3F30804BDC4EF86B5691C5E585A0301" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_VientoFundingIIInc.duein2023Member" xlink:label="loc_nrg_VientoFundingIIInc.duein2023Member_6DFF0DEE9C37D19A956B1C5E585B4539" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_VientoFundingIIInc.duein2023Member_6DFF0DEE9C37D19A956B1C5E585B4539" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NrgEnergyCenterMinneapolisLlcSeniorSecuredNotesMember" xlink:label="loc_nrg_NrgEnergyCenterMinneapolisLlcSeniorSecuredNotesMember_5E098EB0286FFD6DB2DF1C5E585B488F" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_NrgEnergyCenterMinneapolisLlcSeniorSecuredNotesMember_5E098EB0286FFD6DB2DF1C5E585B488F" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGEnergyCenterMinneapolisSeriesDNotesMember" xlink:label="loc_nrg_NRGEnergyCenterMinneapolisSeriesDNotesMember_20217A5BB116EB5F96661C5E585B9FA9" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_NRGEnergyCenterMinneapolisSeriesDNotesMember_20217A5BB116EB5F96661C5E585B9FA9" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_LaredoRidgeWindLLCduein2026Member" xlink:label="loc_nrg_LaredoRidgeWindLLCduein2026Member_4A00EA9DE6D991004A6A1C5E585B9047" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_LaredoRidgeWindLLCduein2026Member_4A00EA9DE6D991004A6A1C5E585B9047" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_OtherDebtMember" xlink:label="loc_nrg_OtherDebtMember_14D0B585E568BB96829D1C5E585B4953" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_OtherDebtMember_14D0B585E568BB96829D1C5E585B4953" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_UtahSolarPortfoliodue2022Member" xlink:label="loc_nrg_UtahSolarPortfoliodue2022Member_604F02D3E474B57B9D7A1C5E585B3ADF" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_UtahSolarPortfoliodue2022Member_604F02D3E474B57B9D7A1C5E585B3ADF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProjectMember" xlink:label="loc_us-gaap_ProjectMember_FB9C219737DEBA26EAB31C5E585BDF3C" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_us-gaap_ProjectMember_FB9C219737DEBA26EAB31C5E585BDF3C" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_WestHoldingsCreditAgreementdue2023TrancheBMember" xlink:label="loc_nrg_WestHoldingsCreditAgreementdue2023TrancheBMember_9D20E875E8D64ACD1D871C5E585BA47C" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_WestHoldingsCreditAgreementdue2023TrancheBMember_9D20E875E8D64ACD1D871C5E585BA47C" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_MarshLandingTrancheBdue2023Member" xlink:label="loc_nrg_MarshLandingTrancheBdue2023Member_A3AAACD36A238BDD4DFE1C5E585B845E" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_MarshLandingTrancheBdue2023Member_A3AAACD36A238BDD4DFE1C5E585B845E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AlpineFinancingAgreementDue2022Member" xlink:label="loc_nrg_AlpineFinancingAgreementDue2022Member_1F98A134ADDF3334A53B1C5E585CB010" xlink:type="locator" />
    <link:definitionArc order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_AlpineFinancingAgreementDue2022Member_1F98A134ADDF3334A53B1C5E585CB010" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AltaWindIVleasefinancingarrangementdue2034and2035Member" xlink:label="loc_nrg_AltaWindIVleasefinancingarrangementdue2034and2035Member_D2415FFED0102E45A1291C5E585C646D" xlink:type="locator" />
    <link:definitionArc order="24" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_AltaWindIVleasefinancingarrangementdue2034and2035Member_D2415FFED0102E45A1291C5E585C646D" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AlpineMember" xlink:label="loc_nrg_AlpineMember_D21F9EDD9E68AB5E03EE1C5E585C068D" xlink:type="locator" />
    <link:definitionArc order="25" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_AlpineMember_D21F9EDD9E68AB5E03EE1C5E585C068D" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CvsrFinancingAgreementMember" xlink:label="loc_nrg_CvsrFinancingAgreementMember_7CEC7F25C5E42DB034851C5E585CE00F" xlink:type="locator" />
    <link:definitionArc order="26" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_CvsrFinancingAgreementMember_7CEC7F25C5E42DB034851C5E585CE00F" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CVSRHoldcodue2037Member" xlink:label="loc_nrg_CVSRHoldcodue2037Member_3239030D0D51D26835111C5E585C8CB1" xlink:type="locator" />
    <link:definitionArc order="27" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_385631509E67CAC6645E1C5E58596284" xlink:to="loc_nrg_CVSRHoldcodue2037Member_3239030D0D51D26835111C5E585C8CB1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableRateAxis" xlink:label="loc_us-gaap_VariableRateAxis_B1BDCF920D212DDC5D3D1C5E585C6E91" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_BD811BAFAC679097A6D61C5E58589A03" xlink:to="loc_us-gaap_VariableRateAxis_B1BDCF920D212DDC5D3D1C5E585C6E91" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_090D48ADF3495D9EF4F41C5E585CCADB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_B1BDCF920D212DDC5D3D1C5E585C6E91" xlink:to="loc_us-gaap_VariableRateDomain_090D48ADF3495D9EF4F41C5E585CCADB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_090D48ADF3495D9EF4F41C5E585CCADB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_B1BDCF920D212DDC5D3D1C5E585C6E91" xlink:to="loc_us-gaap_VariableRateDomain_090D48ADF3495D9EF4F41C5E585CCADB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodAxis" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_B04C296EBF4CC4A7FC7D1C5E585CD148" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_BD811BAFAC679097A6D61C5E58589A03" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_B04C296EBF4CC4A7FC7D1C5E585CD148" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_3FD614406337DF1F17CE1C5E585C2304_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_B04C296EBF4CC4A7FC7D1C5E585CD148" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_3FD614406337DF1F17CE1C5E585C2304_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_3FD614406337DF1F17CE1C5E585C2304" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_B04C296EBF4CC4A7FC7D1C5E585CD148" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_3FD614406337DF1F17CE1C5E585C2304" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SeniorNotes" xlink:label="loc_us-gaap_SeniorNotes_5C3AFE0997EC9D4D501B1C5E585DF02A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_45BA2B77D0D23BAE48A81C5E585C09A1" xlink:to="loc_us-gaap_SeniorNotes_5C3AFE0997EC9D4D501B1C5E585DF02A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToAffiliateNoncurrent" xlink:label="loc_us-gaap_DueToAffiliateNoncurrent_C119A91FB7D18CA2661C1C5E585D6BDC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_45BA2B77D0D23BAE48A81C5E585C09A1" xlink:to="loc_us-gaap_DueToAffiliateNoncurrent_C119A91FB7D18CA2661C1C5E585D6BDC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_42615533FE505E1200DF1C5E585D3DAE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_45BA2B77D0D23BAE48A81C5E585C09A1" xlink:to="loc_us-gaap_LongTermDebt_42615533FE505E1200DF1C5E585D3DAE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_077EF0E736C71368DCC01C5E585D4A30" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_45BA2B77D0D23BAE48A81C5E585C09A1" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_077EF0E736C71368DCC01C5E585D4A30" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_7F6D71C6A19B5507C0AB1C5E585D9ACB" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_45BA2B77D0D23BAE48A81C5E585C09A1" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_7F6D71C6A19B5507C0AB1C5E585D9ACB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentDescriptionOfVariableRateBasis" xlink:label="loc_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_540A3FDEDF8FCC5D443D1C5E585DE2DA" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_45BA2B77D0D23BAE48A81C5E585C09A1" xlink:to="loc_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_540A3FDEDF8FCC5D443D1C5E585DE2DA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_932588648B0A1DA589B81C5E585D90B7" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_45BA2B77D0D23BAE48A81C5E585C09A1" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_932588648B0A1DA589B81C5E585D90B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_0808EB45D8E80C0192F11C5E585D7558" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_45BA2B77D0D23BAE48A81C5E585C09A1" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_0808EB45D8E80C0192F11C5E585D7558" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredFinanceCostsNet" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_AA2200D94AA236093D771C5E585E60CB" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_45BA2B77D0D23BAE48A81C5E585C09A1" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_AA2200D94AA236093D771C5E585E60CB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_DCB853D4489049266F151C5E585E7A41" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_45BA2B77D0D23BAE48A81C5E585C09A1" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_DCB853D4489049266F151C5E585E7A41" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfDebt" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfDebt_53486D7EEB459AEFBF941C5E585EA885" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_45BA2B77D0D23BAE48A81C5E585C09A1" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfDebt_53486D7EEB459AEFBF941C5E585EA885" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/LongTermDebtTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/NatureOfBusiness" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/NatureOfBusinessDetails" xlink:type="extended">
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BasisofPresentationLineItems" xlink:label="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:type="locator" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NatureOfBusinessTable" xlink:label="loc_nrg_NatureOfBusinessTable_8E7FEE804248837EEE221C5E59D4A654" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_nrg_NatureOfBusinessTable_8E7FEE804248837EEE221C5E59D4A654" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_6AC1C7B74B9368E3BA411C5E59D464B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_NatureOfBusinessTable_8E7FEE804248837EEE221C5E59D4A654" xlink:to="loc_us-gaap_DebtInstrumentAxis_6AC1C7B74B9368E3BA411C5E59D464B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_9563DB1D335A8BEF52F01C5E59D45045_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_6AC1C7B74B9368E3BA411C5E59D464B5" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_9563DB1D335A8BEF52F01C5E59D45045_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_9563DB1D335A8BEF52F01C5E59D45045" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_6AC1C7B74B9368E3BA411C5E59D464B5" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_9563DB1D335A8BEF52F01C5E59D45045" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BuckthornSolarDropDownAssetMember" xlink:label="loc_nrg_BuckthornSolarDropDownAssetMember_FF11BFE6CC5142D3CCA41C5E59D59FE2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_9563DB1D335A8BEF52F01C5E59D45045" xlink:to="loc_nrg_BuckthornSolarDropDownAssetMember_FF11BFE6CC5142D3CCA41C5E59D59FE2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E539404171091BCB01DF1C5E59D5246D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_NatureOfBusinessTable_8E7FEE804248837EEE221C5E59D4A654" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E539404171091BCB01DF1C5E59D5246D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_216B821A8968A81C4B8F1C5E59D58DB5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E539404171091BCB01DF1C5E59D5246D" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_216B821A8968A81C4B8F1C5E59D58DB5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_216B821A8968A81C4B8F1C5E59D58DB5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E539404171091BCB01DF1C5E59D5246D" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_216B821A8968A81C4B8F1C5E59D58DB5" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_UnconsolidatedSolarPartnershipsMember" xlink:label="loc_nrg_UnconsolidatedSolarPartnershipsMember_723CBF1674E40EED13FF1C5E59D5DAF7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_216B821A8968A81C4B8F1C5E59D58DB5" xlink:to="loc_nrg_UnconsolidatedSolarPartnershipsMember_723CBF1674E40EED13FF1C5E59D5DAF7" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_August2017DropDownAssetsMember" xlink:label="loc_nrg_August2017DropDownAssetsMember_4CE16A0B6C2DBA9DD3FC1C5E59D57ACF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_216B821A8968A81C4B8F1C5E59D58DB5" xlink:to="loc_nrg_August2017DropDownAssetsMember_4CE16A0B6C2DBA9DD3FC1C5E59D57ACF" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AguaCalienteMember" xlink:label="loc_nrg_AguaCalienteMember_4A05532B2687C5CD29E61C5E59D5ED61" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_216B821A8968A81C4B8F1C5E59D58DB5" xlink:to="loc_nrg_AguaCalienteMember_4A05532B2687C5CD29E61C5E59D5ED61" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_March2017DropDownAssetsMember" xlink:label="loc_nrg_March2017DropDownAssetsMember_0AE255BCB82F144C18E41C5E59D55AF7" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_216B821A8968A81C4B8F1C5E59D58DB5" xlink:to="loc_nrg_March2017DropDownAssetsMember_0AE255BCB82F144C18E41C5E59D55AF7" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AguaCalienteBorrower2Member" xlink:label="loc_nrg_AguaCalienteBorrower2Member_D8EE4E4A9E5811D97C4F1C5E59D5D652" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_216B821A8968A81C4B8F1C5E59D58DB5" xlink:to="loc_nrg_AguaCalienteBorrower2Member_D8EE4E4A9E5811D97C4F1C5E59D5D652" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_73F7AEF34DE62CE872EF1C5E59D5C393" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_NatureOfBusinessTable_8E7FEE804248837EEE221C5E59D4A654" xlink:to="loc_us-gaap_StatementClassOfStockAxis_73F7AEF34DE62CE872EF1C5E59D5C393" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_E1204BDD5B44C1455DCB1C5E59D5AF3A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_73F7AEF34DE62CE872EF1C5E59D5C393" xlink:to="loc_us-gaap_ClassOfStockDomain_E1204BDD5B44C1455DCB1C5E59D5AF3A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_E1204BDD5B44C1455DCB1C5E59D5AF3A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_73F7AEF34DE62CE872EF1C5E59D5C393" xlink:to="loc_us-gaap_ClassOfStockDomain_E1204BDD5B44C1455DCB1C5E59D5AF3A" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CommonClassDMember" xlink:label="loc_nrg_CommonClassDMember_ADE062854A1CF74A68031C5E59D63B5F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_E1204BDD5B44C1455DCB1C5E59D5AF3A" xlink:to="loc_nrg_CommonClassDMember_ADE062854A1CF74A68031C5E59D63B5F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonClassBMember" xlink:label="loc_us-gaap_CommonClassBMember_1F9E3FD8947110D2DC211C5E59D636B1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_E1204BDD5B44C1455DCB1C5E59D5AF3A" xlink:to="loc_us-gaap_CommonClassBMember_1F9E3FD8947110D2DC211C5E59D636B1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember_EBC01C9E5C81DDF428A51C5E59D62DA7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_E1204BDD5B44C1455DCB1C5E59D5AF3A" xlink:to="loc_us-gaap_CommonClassAMember_EBC01C9E5C81DDF428A51C5E59D62DA7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonClassCMember" xlink:label="loc_us-gaap_CommonClassCMember_679D8782D9015A01BCBD1C5E59D65C66" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_E1204BDD5B44C1455DCB1C5E59D5AF3A" xlink:to="loc_us-gaap_CommonClassCMember_679D8782D9015A01BCBD1C5E59D65C66" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerAxis" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_2BF539DB8BB7CD54D35C1C5E59D6DBC5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_NatureOfBusinessTable_8E7FEE804248837EEE221C5E59D4A654" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_2BF539DB8BB7CD54D35C1C5E59D6DBC5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerDomain" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_69B9C8631F8D147655E51C5E59D673B1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_2BF539DB8BB7CD54D35C1C5E59D6DBC5" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_69B9C8631F8D147655E51C5E59D673B1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerDomain" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_69B9C8631F8D147655E51C5E59D673B1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_2BF539DB8BB7CD54D35C1C5E59D6DBC5" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_69B9C8631F8D147655E51C5E59D673B1" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SouthernCaliforniaEdisonMember" xlink:label="loc_nrg_SouthernCaliforniaEdisonMember_D0EDE5453368960097BE1C5E59D63437" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_69B9C8631F8D147655E51C5E59D673B1" xlink:to="loc_nrg_SouthernCaliforniaEdisonMember_D0EDE5453368960097BE1C5E59D63437" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PacificGasandElectricMember" xlink:label="loc_nrg_PacificGasandElectricMember_6B20B1BBE4306E3411001C5E59D6410F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_69B9C8631F8D147655E51C5E59D673B1" xlink:to="loc_nrg_PacificGasandElectricMember_6B20B1BBE4306E3411001C5E59D6410F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_E588E26A205DFBA562EE1C5E59D666BA" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_NatureOfBusinessTable_8E7FEE804248837EEE221C5E59D4A654" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_E588E26A205DFBA562EE1C5E59D666BA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_57DE8F99BC6776BF29D61C5E59D69C1E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_E588E26A205DFBA562EE1C5E59D666BA" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_57DE8F99BC6776BF29D61C5E59D69C1E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_57DE8F99BC6776BF29D61C5E59D69C1E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_E588E26A205DFBA562EE1C5E59D666BA" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_57DE8F99BC6776BF29D61C5E59D69C1E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BuckthornSolarDropDownAssetMember" xlink:label="loc_nrg_BuckthornSolarDropDownAssetMember_145FFEFA694DDDAB32601C5E59D6E155" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_57DE8F99BC6776BF29D61C5E59D69C1E" xlink:to="loc_nrg_BuckthornSolarDropDownAssetMember_145FFEFA694DDDAB32601C5E59D6E155" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_August2017DropDownAssetsMember" xlink:label="loc_nrg_August2017DropDownAssetsMember_4B2FD1F91BF31EF3B6DE1C5E59D62207" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_57DE8F99BC6776BF29D61C5E59D69C1E" xlink:to="loc_nrg_August2017DropDownAssetsMember_4B2FD1F91BF31EF3B6DE1C5E59D62207" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_November2015DropDownAssetsMember" xlink:label="loc_nrg_November2015DropDownAssetsMember_F2D56770A38A827A30121C5E59D74789" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_57DE8F99BC6776BF29D61C5E59D69C1E" xlink:to="loc_nrg_November2015DropDownAssetsMember_F2D56770A38A827A30121C5E59D74789" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CvsrMember" xlink:label="loc_nrg_CvsrMember_BC7B7F43B90BF23416711C5E59D7C913" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_57DE8F99BC6776BF29D61C5E59D69C1E" xlink:to="loc_nrg_CvsrMember_BC7B7F43B90BF23416711C5E59D7C913" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_0833E3FD4F26047EBBEC1C5E59D76F49" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_NatureOfBusinessTable_8E7FEE804248837EEE221C5E59D4A654" xlink:to="loc_dei_LegalEntityAxis_0833E3FD4F26047EBBEC1C5E59D76F49" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_0833E3FD4F26047EBBEC1C5E59D76F49" xlink:to="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_0833E3FD4F26047EBBEC1C5E59D76F49" xlink:to="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SpringCanyonMember" xlink:label="loc_nrg_SpringCanyonMember_372898DC48FBF2B1F9901C5E59D7E376" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_SpringCanyonMember_372898DC48FBF2B1F9901C5E59D7E376" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldMember" xlink:label="loc_nrg_NRGYieldMember_AF35038670EB7837DCB41C5E59D7ABE0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_NRGYieldMember_AF35038670EB7837DCB41C5E59D7ABE0" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NrgYieldIncMember" xlink:label="loc_nrg_NrgYieldIncMember_B0D6D6A3DF9380EB13851C5E59D7B63D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_NrgYieldIncMember_B0D6D6A3DF9380EB13851C5E59D7B63D" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldLLCMember" xlink:label="loc_nrg_NRGYieldLLCMember_A4D363DB72851A880B011C5E59D7C295" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_NRGYieldLLCMember_A4D363DB72851A880B011C5E59D7C295" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NrgMember" xlink:label="loc_nrg_NrgMember_EAA40614E2E69094C2431C5E59D89148" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_NrgMember_EAA40614E2E69094C2431C5E59D89148" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_GenConnMiddletownMember" xlink:label="loc_nrg_GenConnMiddletownMember_82A862C5127B6E77141E1C5E59D8D712" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_GenConnMiddletownMember_82A862C5127B6E77141E1C5E59D8D712" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_GenConnDevonMember" xlink:label="loc_nrg_GenConnDevonMember_3B0476048C79ED0328191C5E59D8E74E" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_GenConnDevonMember_3B0476048C79ED0328191C5E59D8E74E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_MarshLandingMember" xlink:label="loc_nrg_MarshLandingMember_F43AB3AC79BEE0BA47581C5E59D865DD" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_MarshLandingMember_F43AB3AC79BEE0BA47581C5E59D865DD" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ElSegundoMember" xlink:label="loc_nrg_ElSegundoMember_EB831A50D3951C9ADBB41C5E59D8E639" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_ElSegundoMember_EB831A50D3951C9ADBB41C5E59D8E639" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_WalnutCreekMember" xlink:label="loc_nrg_WalnutCreekMember_7DE23F12006B46599C631C5E59D85964" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_WalnutCreekMember_7DE23F12006B46599C631C5E59D85964" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AguaCalienteMember" xlink:label="loc_nrg_AguaCalienteMember_F7D2600C3477F0F5A8071C5E59D8FEDF" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_AguaCalienteMember_F7D2600C3477F0F5A8071C5E59D8FEDF" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AlpineMember" xlink:label="loc_nrg_AlpineMember_D49D207F07FFB9DD4F6A1C5E59D8D869" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_AlpineMember_D49D207F07FFB9DD4F6A1C5E59D8D869" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AvenalMember" xlink:label="loc_nrg_AvenalMember_0CFB0DB7C9B545E889B01C5E59D8F359" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_AvenalMember_0CFB0DB7C9B545E889B01C5E59D8F359" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AvraValleyMember" xlink:label="loc_nrg_AvraValleyMember_F8AF7348CAE5D97348F11C5E59D80E1F" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_AvraValleyMember_F8AF7348CAE5D97348F11C5E59D80E1F" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NrgSolarBlytheLlcMember" xlink:label="loc_nrg_NrgSolarBlytheLlcMember_431582C25D9BC101BB631C5E59D8DFE4" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_NrgSolarBlytheLlcMember_431582C25D9BC101BB631C5E59D8DFE4" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BorregoMember" xlink:label="loc_nrg_BorregoMember_CD0282A0683DCB22C70E1C5E59D96611" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_BorregoMember_CD0282A0683DCB22C70E1C5E59D96611" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CvsrMember" xlink:label="loc_nrg_CvsrMember_3E0F979ABEFF8BB4D6DE1C5E59D90216" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_CvsrMember_3E0F979ABEFF8BB4D6DE1C5E59D90216" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_DesertSunlightMember" xlink:label="loc_nrg_DesertSunlightMember_16357F340CD6A16034F11C5E59D9615D" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_DesertSunlightMember_16357F340CD6A16034F11C5E59D9615D" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_KansasSouthMember" xlink:label="loc_nrg_KansasSouthMember_AB45039A6EB70DBA49891C5E59D96039" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_KansasSouthMember_AB45039A6EB70DBA49891C5E59D96039" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NrgSolarRoadrunnerLlcMember" xlink:label="loc_nrg_NrgSolarRoadrunnerLlcMember_4286E3AE6EB809CF23FC1C5E59D920EF" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_NrgSolarRoadrunnerLlcMember_4286E3AE6EB809CF23FC1C5E59D920EF" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_TaHighDesertLlcMember" xlink:label="loc_nrg_TaHighDesertLlcMember_23B9F9E352B0F32D49FA1C5E59D942EB" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_TaHighDesertLlcMember_23B9F9E352B0F32D49FA1C5E59D942EB" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_UtahPortfolioMember" xlink:label="loc_nrg_UtahPortfolioMember_EEF935EA31C95A5B8D501C5E59D9C7F3" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_UtahPortfolioMember_EEF935EA31C95A5B8D501C5E59D9C7F3" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AZDGSolarProjectsMember" xlink:label="loc_nrg_AZDGSolarProjectsMember_B2D1A6BBC12A00EF76691C5E59D93627" xlink:type="locator" />
    <link:definitionArc order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_AZDGSolarProjectsMember_B2D1A6BBC12A00EF76691C5E59D93627" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SPPProjectsMember" xlink:label="loc_nrg_SPPProjectsMember_BA925A38BB665E34D8101C5E59D976AB" xlink:type="locator" />
    <link:definitionArc order="24" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_SPPProjectsMember_BA925A38BB665E34D8101C5E59D976AB" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_OtherDGAssetsMember" xlink:label="loc_nrg_OtherDGAssetsMember_385CB6D0C4B457532B5D1C5E59D95869" xlink:type="locator" />
    <link:definitionArc order="25" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_OtherDGAssetsMember_385CB6D0C4B457532B5D1C5E59D95869" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PFMGDGSolarProjectsMember" xlink:label="loc_nrg_PFMGDGSolarProjectsMember_DE27D138D1308333B4271C5E59D92E76" xlink:type="locator" />
    <link:definitionArc order="26" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_PFMGDGSolarProjectsMember_DE27D138D1308333B4271C5E59D92E76" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AltaIMember" xlink:label="loc_nrg_AltaIMember_F2DDA38180DFA694B8EB1C5E59D9CBC5" xlink:type="locator" />
    <link:definitionArc order="27" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_AltaIMember_F2DDA38180DFA694B8EB1C5E59D9CBC5" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AltaIIMember" xlink:label="loc_nrg_AltaIIMember_A2660D898136E27C11951C5E59D9EA95" xlink:type="locator" />
    <link:definitionArc order="28" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_AltaIIMember_A2660D898136E27C11951C5E59D9EA95" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AltaIIIMember" xlink:label="loc_nrg_AltaIIIMember_D40D57AD15934CD345821C5E59DA87E7" xlink:type="locator" />
    <link:definitionArc order="29" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_AltaIIIMember_D40D57AD15934CD345821C5E59DA87E7" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AltaIVMember" xlink:label="loc_nrg_AltaIVMember_D5B2CDDA6EFC3E73037F1C5E59DA38A4" xlink:type="locator" />
    <link:definitionArc order="30" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_AltaIVMember_D5B2CDDA6EFC3E73037F1C5E59DA38A4" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AltaVMember" xlink:label="loc_nrg_AltaVMember_763EC91C5930DBAA1B8A1C5E59DA81F7" xlink:type="locator" />
    <link:definitionArc order="31" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_AltaVMember_763EC91C5930DBAA1B8A1C5E59DA81F7" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AltaXMember" xlink:label="loc_nrg_AltaXMember_5E4D05653C65A2FF24B71C5E59DA7C6A" xlink:type="locator" />
    <link:definitionArc order="32" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_AltaXMember_5E4D05653C65A2FF24B71C5E59DA7C6A" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AltaXIMember" xlink:label="loc_nrg_AltaXIMember_023A0D868C9F723195FB1C5E59DA5818" xlink:type="locator" />
    <link:definitionArc order="33" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_AltaXIMember_023A0D868C9F723195FB1C5E59DA5818" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SouthTrentHoldingLlcMember" xlink:label="loc_nrg_SouthTrentHoldingLlcMember_343F73B1A4F69BB2EA4F1C5E59DA9E02" xlink:type="locator" />
    <link:definitionArc order="34" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_SouthTrentHoldingLlcMember_343F73B1A4F69BB2EA4F1C5E59DA9E02" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SpanishForkMember" xlink:label="loc_nrg_SpanishForkMember_5D5C64849DE01A8270091C5E59DA3C2E" xlink:type="locator" />
    <link:definitionArc order="35" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_SpanishForkMember_5D5C64849DE01A8270091C5E59DA3C2E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_LaredoRidgeMember" xlink:label="loc_nrg_LaredoRidgeMember_5D53BB5F9379293D35CC1C5E59DA3D3B" xlink:type="locator" />
    <link:definitionArc order="36" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_LaredoRidgeMember_5D53BB5F9379293D35CC1C5E59DA3D3B" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_TalogaMember" xlink:label="loc_nrg_TalogaMember_24244CBA8E8FF475D5321C5E59DA8D39" xlink:type="locator" />
    <link:definitionArc order="37" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_TalogaMember_24244CBA8E8FF475D5321C5E59DA8D39" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PinnacleMember" xlink:label="loc_nrg_PinnacleMember_CDDB52753A70B29593351C5E59DA1B4C" xlink:type="locator" />
    <link:definitionArc order="38" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_PinnacleMember_CDDB52753A70B29593351C5E59DA1B4C" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BuffaloBearMember" xlink:label="loc_nrg_BuffaloBearMember_87B955E5222A7ECDD0AF1C5E59DAB07F" xlink:type="locator" />
    <link:definitionArc order="39" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_BuffaloBearMember_87B955E5222A7ECDD0AF1C5E59DAB07F" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SpringCanyonIIMember" xlink:label="loc_nrg_SpringCanyonIIMember_5D5FFB39845EED4FBAF51C5E59DBD318" xlink:type="locator" />
    <link:definitionArc order="40" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_SpringCanyonIIMember_5D5FFB39845EED4FBAF51C5E59DBD318" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SpringCanyonIIIMember" xlink:label="loc_nrg_SpringCanyonIIIMember_F1E0AE1415903C77370D1C5E59DBDEC1" xlink:type="locator" />
    <link:definitionArc order="41" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_SpringCanyonIIIMember_F1E0AE1415903C77370D1C5E59DBDEC1" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CrosswindsMember" xlink:label="loc_nrg_CrosswindsMember_E0952FE4AB1C11150A6A1C5E59DBB7C1" xlink:type="locator" />
    <link:definitionArc order="42" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_CrosswindsMember_E0952FE4AB1C11150A6A1C5E59DBB7C1" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ElbowCreekMember" xlink:label="loc_nrg_ElbowCreekMember_D42913715A384AA189CD1C5E59DB9529" xlink:type="locator" />
    <link:definitionArc order="43" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_ElbowCreekMember_D42913715A384AA189CD1C5E59DB9529" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ElkhornRidgeWindLLCMember" xlink:label="loc_nrg_ElkhornRidgeWindLLCMember_83292E4C8638DFC1F11D1C5E59DB99C1" xlink:type="locator" />
    <link:definitionArc order="44" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_ElkhornRidgeWindLLCMember_83292E4C8638DFC1F11D1C5E59DB99C1" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ForwardMember" xlink:label="loc_nrg_ForwardMember_635A6DF5C7F4F59CD3481C5E59DB3D46" xlink:type="locator" />
    <link:definitionArc order="45" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_ForwardMember_635A6DF5C7F4F59CD3481C5E59DB3D46" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_GoatWindMember" xlink:label="loc_nrg_GoatWindMember_4BD8849089ACDE6C40E51C5E59DB43ED" xlink:type="locator" />
    <link:definitionArc order="46" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_GoatWindMember_4BD8849089ACDE6C40E51C5E59DB43ED" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_HardinMember" xlink:label="loc_nrg_HardinMember_3A51C66C770755E96C7A1C5E59DB309B" xlink:type="locator" />
    <link:definitionArc order="47" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_HardinMember_3A51C66C770755E96C7A1C5E59DB309B" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_LookoutMember" xlink:label="loc_nrg_LookoutMember_8836AC1BDEC0008D21511C5E59DB59EF" xlink:type="locator" />
    <link:definitionArc order="48" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_LookoutMember_8836AC1BDEC0008D21511C5E59DB59EF" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_OdinWindFarmMember" xlink:label="loc_nrg_OdinWindFarmMember_3815133037CCC78E7C231C5E59DC091A" xlink:type="locator" />
    <link:definitionArc order="49" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_OdinWindFarmMember_3815133037CCC78E7C231C5E59DC091A" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SanJuanMesaWindProjectLLCMember" xlink:label="loc_nrg_SanJuanMesaWindProjectLLCMember_4EE1840DE1FC8C6BC6E21C5E59DC88CE" xlink:type="locator" />
    <link:definitionArc order="50" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_SanJuanMesaWindProjectLLCMember_4EE1840DE1FC8C6BC6E21C5E59DC88CE" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SleepingBearMember" xlink:label="loc_nrg_SleepingBearMember_2D16B6D7BE71BE62D75A1C5E59DCA3B0" xlink:type="locator" />
    <link:definitionArc order="51" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_SleepingBearMember_2D16B6D7BE71BE62D75A1C5E59DCA3B0" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_WildoradoMember" xlink:label="loc_nrg_WildoradoMember_8AE4FE3E80E189DAAA061C5E59DC450E" xlink:type="locator" />
    <link:definitionArc order="52" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_WildoradoMember_8AE4FE3E80E189DAAA061C5E59DC450E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ThermalMember" xlink:label="loc_nrg_ThermalMember_BD44D9E346BB3143DF1D1C5E59DC65F8" xlink:type="locator" />
    <link:definitionArc order="53" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_ThermalMember_BD44D9E346BB3143DF1D1C5E59DC65F8" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGEnergyCenterDoverMember" xlink:label="loc_nrg_NRGEnergyCenterDoverMember_B826A6EC80B7374BED1A1C5E59DC309C" xlink:type="locator" />
    <link:definitionArc order="54" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_NRGEnergyCenterDoverMember_B826A6EC80B7374BED1A1C5E59DC309C" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGRPVHoldcoMember" xlink:label="loc_nrg_NRGRPVHoldcoMember_7465D314EF062CF042211C5E59DC03CB" xlink:type="locator" />
    <link:definitionArc order="55" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7131930AB97BA570661D1C5E59D72B5E" xlink:to="loc_nrg_NRGRPVHoldcoMember_7465D314EF062CF042211C5E59DC03CB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CounterpartyNameAxis" xlink:label="loc_us-gaap_CounterpartyNameAxis_C73A718731AD04AEF2D91C5E59DC7CCA" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_NatureOfBusinessTable_8E7FEE804248837EEE221C5E59D4A654" xlink:to="loc_us-gaap_CounterpartyNameAxis_C73A718731AD04AEF2D91C5E59DC7CCA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_767BBB450BB148C74B791C5E59DC14E2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CounterpartyNameAxis_C73A718731AD04AEF2D91C5E59DC7CCA" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_767BBB450BB148C74B791C5E59DC14E2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RepurchaseAgreementCounterpartyNameDomain" xlink:label="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_767BBB450BB148C74B791C5E59DC14E2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CounterpartyNameAxis_C73A718731AD04AEF2D91C5E59DC7CCA" xlink:to="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_767BBB450BB148C74B791C5E59DC14E2" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldMember" xlink:label="loc_nrg_NRGYieldMember_2346B682362FBE42F98D1C5E59DCF355" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_767BBB450BB148C74B791C5E59DC14E2" xlink:to="loc_nrg_NRGYieldMember_2346B682362FBE42F98D1C5E59DCF355" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NrgMember" xlink:label="loc_nrg_NrgMember_862446A8FD1153C250E61C5E59DCCBDF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_767BBB450BB148C74B791C5E59DC14E2" xlink:to="loc_nrg_NrgMember_862446A8FD1153C250E61C5E59DCCBDF" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldLLCMember" xlink:label="loc_nrg_NRGYieldLLCMember_F530319A535FE66E94FC1C5E59DDCA31" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_767BBB450BB148C74B791C5E59DC14E2" xlink:to="loc_nrg_NRGYieldLLCMember_F530319A535FE66E94FC1C5E59DDCA31" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NrgYieldIncMember" xlink:label="loc_nrg_NrgYieldIncMember_D819A839206C35CD72281C5E59DDE077" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RepurchaseAgreementCounterpartyNameDomain_767BBB450BB148C74B791C5E59DC14E2" xlink:to="loc_nrg_NrgYieldIncMember_D819A839206C35CD72281C5E59DDE077" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationFacilitiesByTypeAxis" xlink:label="loc_nrg_PowerGenerationFacilitiesByTypeAxis_DB477D2132A734FDA6721C5E59DD5701" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_NatureOfBusinessTable_8E7FEE804248837EEE221C5E59D4A654" xlink:to="loc_nrg_PowerGenerationFacilitiesByTypeAxis_DB477D2132A734FDA6721C5E59DD5701" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationFacilitiesTypeDomain" xlink:label="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC61857A9360B199FCB11C5E59DD725F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_nrg_PowerGenerationFacilitiesByTypeAxis_DB477D2132A734FDA6721C5E59DD5701" xlink:to="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC61857A9360B199FCB11C5E59DD725F_default" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationFacilitiesTypeDomain" xlink:label="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC61857A9360B199FCB11C5E59DD725F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_nrg_PowerGenerationFacilitiesByTypeAxis_DB477D2132A734FDA6721C5E59DD5701" xlink:to="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC61857A9360B199FCB11C5E59DD725F" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ConventionalGenerationUtilityScaleSolarDistributedSolarandWindMember" xlink:label="loc_nrg_ConventionalGenerationUtilityScaleSolarDistributedSolarandWindMember_822F3A7D85D2278BCFDF1C5E59DDB3D9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC61857A9360B199FCB11C5E59DD725F" xlink:to="loc_nrg_ConventionalGenerationUtilityScaleSolarDistributedSolarandWindMember_822F3A7D85D2278BCFDF1C5E59DDB3D9" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_DistributedSolarMember" xlink:label="loc_nrg_DistributedSolarMember_90F1CB7C02B69DCE169A1C5E59DDA858" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC61857A9360B199FCB11C5E59DD725F" xlink:to="loc_nrg_DistributedSolarMember_90F1CB7C02B69DCE169A1C5E59DDA858" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_WindFarmsMember" xlink:label="loc_nrg_WindFarmsMember_98283B5103715D00BBAE1C5E59DDA42E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC61857A9360B199FCB11C5E59DD725F" xlink:to="loc_nrg_WindFarmsMember_98283B5103715D00BBAE1C5E59DDA42E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ThermalMember" xlink:label="loc_nrg_ThermalMember_15851CC99664D61A16441C5E59DD898E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC61857A9360B199FCB11C5E59DD725F" xlink:to="loc_nrg_ThermalMember_15851CC99664D61A16441C5E59DD898E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGEnergyCenterDoverMember" xlink:label="loc_nrg_NRGEnergyCenterDoverMember_BA87FDDC6231F1FC25921C5E59DD176D" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC61857A9360B199FCB11C5E59DD725F" xlink:to="loc_nrg_NRGEnergyCenterDoverMember_BA87FDDC6231F1FC25921C5E59DD176D" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ConventionalGenerationMember" xlink:label="loc_nrg_ConventionalGenerationMember_0948B465A531B692370E1C5E59DD3EFF" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC61857A9360B199FCB11C5E59DD725F" xlink:to="loc_nrg_ConventionalGenerationMember_0948B465A531B692370E1C5E59DD3EFF" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_UtilityScaleSolarMember" xlink:label="loc_nrg_UtilityScaleSolarMember_953314C7D02C02117FDD1C5E59DD8F9C" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC61857A9360B199FCB11C5E59DD725F" xlink:to="loc_nrg_UtilityScaleSolarMember_953314C7D02C02117FDD1C5E59DD8F9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SaleOfStockPercentageOfOwnershipAfterTransaction" xlink:label="loc_us-gaap_SaleOfStockPercentageOfOwnershipAfterTransaction_8923A464359E16D8DA091C5E59DEE789" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_us-gaap_SaleOfStockPercentageOfOwnershipAfterTransaction_8923A464359E16D8DA091C5E59DEE789" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_MegawattsThermalEquivalentAvailableUnderrighttouseProvisions" xlink:label="loc_nrg_MegawattsThermalEquivalentAvailableUnderrighttouseProvisions_2EFCFD168717EA57ADC61C5E59DE4F9C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_nrg_MegawattsThermalEquivalentAvailableUnderrighttouseProvisions_2EFCFD168717EA57ADC61C5E59DE4F9C" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PercentageofNRGsOwnership" xlink:label="loc_nrg_PercentageofNRGsOwnership_2BF35266658FD788E9E01C5E59DE66F0" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_nrg_PercentageofNRGsOwnership_2BF35266658FD788E9E01C5E59DE66F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_A98BD8B6DFEC4FE221F01C5E59DE6701" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_A98BD8B6DFEC4FE221F01C5E59DE6701" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersVotingInterest" xlink:label="loc_nrg_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersVotingInterest_54A102A7616DB5AD51641C5E59DEBAD1" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_nrg_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersVotingInterest_54A102A7616DB5AD51641C5E59DEBAD1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_DCBE3E888A3E7B3D01B41C5E59DED0D5" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_DCBE3E888A3E7B3D01B41C5E59DED0D5" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PercentageOfOwnership" xlink:label="loc_nrg_PercentageOfOwnership_487BA1FD5C90CF12AC191C5E59DE165D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_nrg_PercentageOfOwnership_487BA1FD5C90CF12AC191C5E59DE165D" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SteamAndChilledWaterCapacityMegawattsThermalEquivalent" xlink:label="loc_nrg_SteamAndChilledWaterCapacityMegawattsThermalEquivalent_6FBD68CB9A8BF43A9BDA1C5E59DED8D4" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_nrg_SteamAndChilledWaterCapacityMegawattsThermalEquivalent_6FBD68CB9A8BF43A9BDA1C5E59DED8D4" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationCapacityMegawatts" xlink:label="loc_nrg_PowerGenerationCapacityMegawatts_ED937C9C63EF46B138601C5E59DEB742" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_nrg_PowerGenerationCapacityMegawatts_ED937C9C63EF46B138601C5E59DEB742" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:label="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_A6A9B0D99DC71D6CF1461C5E59DF1CA8" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_A6A9B0D99DC71D6CF1461C5E59DF1CA8" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationCapacityMegawattsandMegawattThermalEquivalent" xlink:label="loc_nrg_PowerGenerationCapacityMegawattsandMegawattThermalEquivalent_C1AF751BF14EC23226E01C5E59DFE032" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_nrg_PowerGenerationCapacityMegawattsandMegawattThermalEquivalent_C1AF751BF14EC23226E01C5E59DFE032" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_WeightedAverageRemainingPPATerm" xlink:label="loc_nrg_WeightedAverageRemainingPPATerm_EBB6149FEA8A653C81DF1C5E59DFF4D6" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_nrg_WeightedAverageRemainingPPATerm_EBB6149FEA8A653C81DF1C5E59DFF4D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_277874A2879E83CBB1AE1C5E59DF269C" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_277874A2879E83CBB1AE1C5E59DF269C" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BusinessAcquisitionConsiderationTransferredWorkingCapital" xlink:label="loc_nrg_BusinessAcquisitionConsiderationTransferredWorkingCapital_555F69C64BD6D4A93BE71C5E59DFAE35" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_nrg_BusinessAcquisitionConsiderationTransferredWorkingCapital_555F69C64BD6D4A93BE71C5E59DFAE35" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_E6892319B8C821218DC11C5E59DF8208" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_E6892319B8C821218DC11C5E59DF8208" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_E0C8899D2DF40C5F8CEB1C5E59DFF825" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_E0C8899D2DF40C5F8CEB1C5E59DFF825" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationCapacityMegawattsattributedtononcontrollinginterest" xlink:label="loc_nrg_PowerGenerationCapacityMegawattsattributedtononcontrollinginterest_C953848A21BE97D822931C5E59DFCC21" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_nrg_PowerGenerationCapacityMegawattsattributedtononcontrollinginterest_C953848A21BE97D822931C5E59DFCC21" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationCapacityMegawattsincludingportionattributabletononcontrollinginterest" xlink:label="loc_nrg_PowerGenerationCapacityMegawattsincludingportionattributabletononcontrollinginterest_DA55DF50015C921C04E81C5E59DFF52C" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_nrg_PowerGenerationCapacityMegawattsincludingportionattributabletononcontrollinginterest_DA55DF50015C921C04E81C5E59DFF52C" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ProRateShareofDebtHeldbyUnconsolidatedAffiliates" xlink:label="loc_nrg_ProRateShareofDebtHeldbyUnconsolidatedAffiliates_925C1CC417A2669273891C5E59DFE226" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_nrg_ProRateShareofDebtHeldbyUnconsolidatedAffiliates_925C1CC417A2669273891C5E59DFE226" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_F15A78AEA4B3E3A7F8831C5E59E0BBDE" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_BasisofPresentationLineItems_EC11184D1504547854811C5E59DDE8AB" xlink:to="loc_us-gaap_LongTermDebt_F15A78AEA4B3E3A7F8831C5E59E0BBDE" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/NatureOfBusinessNatureOfBusinessTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/RelatedPartyTransactions" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/RelatedPartyTransactionsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_CE1AF195A2C4CCE1B1A9021FAB8B17B6" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_97751C17898DC335C6A5021FAB800CB3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_CE1AF195A2C4CCE1B1A9021FAB8B17B6" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_97751C17898DC335C6A5021FAB800CB3" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_3BB78BFF4F42DBF9657E021FAB81CB11" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_97751C17898DC335C6A5021FAB800CB3" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_3BB78BFF4F42DBF9657E021FAB81CB11" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_8C6E23E88FC64ECCF917021FAB8125F6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_3BB78BFF4F42DBF9657E021FAB81CB11" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_8C6E23E88FC64ECCF917021FAB8125F6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_8C6E23E88FC64ECCF917021FAB8125F6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_3BB78BFF4F42DBF9657E021FAB81CB11" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_8C6E23E88FC64ECCF917021FAB8125F6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_58D4B36C43638DC33511021FAB8125EC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_97751C17898DC335C6A5021FAB800CB3" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_58D4B36C43638DC33511021FAB8125EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_9CE082301DD7403E0FE4021FAB815978_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_58D4B36C43638DC33511021FAB8125EC" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_9CE082301DD7403E0FE4021FAB815978_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_9CE082301DD7403E0FE4021FAB815978" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_58D4B36C43638DC33511021FAB8125EC" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_9CE082301DD7403E0FE4021FAB815978" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_OperationsandMaintenanceservicesMember" xlink:label="loc_nrg_OperationsandMaintenanceservicesMember_F809EF039A58EE62355F021FAB818B32" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_9CE082301DD7403E0FE4021FAB815978" xlink:to="loc_nrg_OperationsandMaintenanceservicesMember_F809EF039A58EE62355F021FAB818B32" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NrgMember" xlink:label="loc_nrg_NrgMember_A5DBAC41154FF51D4CF5021FAB81537F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_9CE082301DD7403E0FE4021FAB815978" xlink:to="loc_nrg_NrgMember_A5DBAC41154FF51D4CF5021FAB81537F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_1157EB993889FAD70AB8021FAB822331" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_97751C17898DC335C6A5021FAB800CB3" xlink:to="loc_dei_LegalEntityAxis_1157EB993889FAD70AB8021FAB822331" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_1157EB993889FAD70AB8021FAB822331" xlink:to="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_1157EB993889FAD70AB8021FAB822331" xlink:to="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGYieldMember" xlink:label="loc_nrg_NRGYieldMember_79FC97B868CF0B0D4629021FAB82CE90" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_NRGYieldMember_79FC97B868CF0B0D4629021FAB82CE90" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NrgYieldIncMember" xlink:label="loc_nrg_NrgYieldIncMember_82B3EAB38ACD0245256A021FAB82A254" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_NrgYieldIncMember_82B3EAB38ACD0245256A021FAB82A254" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_November2015DropDownAssetsMember" xlink:label="loc_nrg_November2015DropDownAssetsMember_F22F53B7DA7B4C019CA1021FAB826DCB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_November2015DropDownAssetsMember_F22F53B7DA7B4C019CA1021FAB826DCB" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ElbowCreekMember" xlink:label="loc_nrg_ElbowCreekMember_90D9D39CBE00C1287DDD021FAB82CE17" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_ElbowCreekMember_90D9D39CBE00C1287DDD021FAB82CE17" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ThermalMember" xlink:label="loc_nrg_ThermalMember_C34FE1F1A8BE76C9CE7B021FAB83096F" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_ThermalMember_C34FE1F1A8BE76C9CE7B021FAB83096F" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_OperationsandMaintenanceservicesMember" xlink:label="loc_nrg_OperationsandMaintenanceservicesMember_E5B6F603864C71518C28021FAB83D86F" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_OperationsandMaintenanceservicesMember_E5B6F603864C71518C28021FAB83D86F" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_WalnutCreekMember" xlink:label="loc_nrg_WalnutCreekMember_6AA98C62B46F0F1D3AFD021FAB83D1D6" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_WalnutCreekMember_6AA98C62B46F0F1D3AFD021FAB83D1D6" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_GceHoldingLlcMember" xlink:label="loc_nrg_GceHoldingLlcMember_9E4989132ADBF32B8DB0021FAB832D8E" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_GceHoldingLlcMember_9E4989132ADBF32B8DB0021FAB832D8E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGEnergyCenterDoverMember" xlink:label="loc_nrg_NRGEnergyCenterDoverMember_B546ECE517A3EA7C9979021FAB834EB4" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_NRGEnergyCenterDoverMember_B546ECE517A3EA7C9979021FAB834EB4" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_MarshLandingMember" xlink:label="loc_nrg_MarshLandingMember_D76BDBEAFD6AF0201FF4021FAB89233B" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_MarshLandingMember_D76BDBEAFD6AF0201FF4021FAB89233B" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ElSegundoMember" xlink:label="loc_nrg_ElSegundoMember_C46E68CE988D0A546EEF021FAB8907B6" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_ElSegundoMember_C46E68CE988D0A546EEF021FAB8907B6" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_GenConnEnergyLlcMember" xlink:label="loc_nrg_GenConnEnergyLlcMember_9FB6C4F7AA20499FC453021FAB89338F" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_GenConnEnergyLlcMember_9FB6C4F7AA20499FC453021FAB89338F" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CvsrMember" xlink:label="loc_nrg_CvsrMember_83EDA72BFE63BE364E52021FAB89F86E" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_CvsrMember_83EDA72BFE63BE364E52021FAB89F86E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGDGPVHoldco2Member" xlink:label="loc_nrg_NRGDGPVHoldco2Member_67EADAE35D59A0CA17C3021FAB896DDE" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_NRGDGPVHoldco2Member_67EADAE35D59A0CA17C3021FAB896DDE" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NECPMember" xlink:label="loc_nrg_NECPMember_CD573E6C1C1CB22CDF8602366189CA79" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_C5F3221A0CDE02F6DB6D021FAB82F9CC" xlink:to="loc_nrg_NECPMember_CD573E6C1C1CB22CDF8602366189CA79" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_579F6253D5A56D1765AF021FAB8A9707" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_97751C17898DC335C6A5021FAB800CB3" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_579F6253D5A56D1765AF021FAB8A9707" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_23FD418558765F14054B021FAB8AF27A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_579F6253D5A56D1765AF021FAB8A9707" xlink:to="loc_us-gaap_RelatedPartyDomain_23FD418558765F14054B021FAB8AF27A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_23FD418558765F14054B021FAB8AF27A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_579F6253D5A56D1765AF021FAB8A9707" xlink:to="loc_us-gaap_RelatedPartyDomain_23FD418558765F14054B021FAB8AF27A" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NrgMember" xlink:label="loc_nrg_NrgMember_87A3D5E4DF88C2FE8048021FAB8A9BF7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_23FD418558765F14054B021FAB8AF27A" xlink:to="loc_nrg_NrgMember_87A3D5E4DF88C2FE8048021FAB8A9BF7" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGRENOMMember" xlink:label="loc_nrg_NRGRENOMMember_C50CF55D8D93AB251C14021FAB8A0109" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_23FD418558765F14054B021FAB8AF27A" xlink:to="loc_nrg_NRGRENOMMember_C50CF55D8D93AB251C14021FAB8A0109" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_BD8D822F969244C0C4E2021FAB8AEB06" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_97751C17898DC335C6A5021FAB800CB3" xlink:to="loc_us-gaap_StatementScenarioAxis_BD8D822F969244C0C4E2021FAB8AEB06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_DDDB84E51BCD464A2E0E021FAB8ABA42_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_BD8D822F969244C0C4E2021FAB8AEB06" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_DDDB84E51BCD464A2E0E021FAB8ABA42_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_DDDB84E51BCD464A2E0E021FAB8ABA42" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_BD8D822F969244C0C4E2021FAB8AEB06" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_DDDB84E51BCD464A2E0E021FAB8ABA42" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioPlanMember" xlink:label="loc_us-gaap_ScenarioPlanMember_95E56B480A39A49DBAE5021FAB8A86AE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScenarioUnspecifiedDomain_DDDB84E51BCD464A2E0E021FAB8ABA42" xlink:to="loc_us-gaap_ScenarioPlanMember_95E56B480A39A49DBAE5021FAB8A86AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ServiceManagementCosts" xlink:label="loc_us-gaap_ServiceManagementCosts_4496C5BD0F91B7C49A93021FAB8B30EE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_CE1AF195A2C4CCE1B1A9021FAB8B17B6" xlink:to="loc_us-gaap_ServiceManagementCosts_4496C5BD0F91B7C49A93021FAB8B30EE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_F59D3BCA49ED7E54376B021FAB8BDB78" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_CE1AF195A2C4CCE1B1A9021FAB8B17B6" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_F59D3BCA49ED7E54376B021FAB8BDB78" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToAffiliateCurrentAndNoncurrent" xlink:label="loc_us-gaap_DueToAffiliateCurrentAndNoncurrent_D3605E9FB48DE18E7DD0021FAB8B2891" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_CE1AF195A2C4CCE1B1A9021FAB8B17B6" xlink:to="loc_us-gaap_DueToAffiliateCurrentAndNoncurrent_D3605E9FB48DE18E7DD0021FAB8B2891" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToAffiliateCurrent" xlink:label="loc_us-gaap_DueToAffiliateCurrent_926E2856F4A9ED15B931021FAB8BA1FF" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_CE1AF195A2C4CCE1B1A9021FAB8B17B6" xlink:to="loc_us-gaap_DueToAffiliateCurrent_926E2856F4A9ED15B931021FAB8BA1FF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToAffiliateNoncurrent" xlink:label="loc_us-gaap_DueToAffiliateNoncurrent_21080B0FC3968ED4EC19021FAB8BDA01" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_CE1AF195A2C4CCE1B1A9021FAB8B17B6" xlink:to="loc_us-gaap_DueToAffiliateNoncurrent_21080B0FC3968ED4EC19021FAB8BDA01" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromRelatedParties" xlink:label="loc_us-gaap_RevenueFromRelatedParties_5BC6704082C5C5A8E97A021FAB8B6B39" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_CE1AF195A2C4CCE1B1A9021FAB8B17B6" xlink:to="loc_us-gaap_RevenueFromRelatedParties_5BC6704082C5C5A8E97A021FAB8B6B39" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty" xlink:label="loc_us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty_E9A461CA0338C8C9223E021FAB8B1FC7" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_CE1AF195A2C4CCE1B1A9021FAB8B17B6" xlink:to="loc_us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty_E9A461CA0338C8C9223E021FAB8B1FC7" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_RelatedPartyTransactionAmounttobePaidUponCompletionofProject" xlink:label="loc_nrg_RelatedPartyTransactionAmounttobePaidUponCompletionofProject_D82302E08BBDE89EA01E0236616329EA" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_CE1AF195A2C4CCE1B1A9021FAB8B17B6" xlink:to="loc_nrg_RelatedPartyTransactionAmounttobePaidUponCompletionofProject_D82302E08BBDE89EA01E0236616329EA" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/RelatedPartyTransactionsRelatedPartyTransactionsTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_073AF0785229703AAAEA180F717F2C3E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_FBADA8C9FE3E3756EA88180F7178283E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_073AF0785229703AAAEA180F717F2C3E" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_FBADA8C9FE3E3756EA88180F7178283E" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_F5EEEF5F0296A0D6F9B9180F7178A18C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_FBADA8C9FE3E3756EA88180F7178283E" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_F5EEEF5F0296A0D6F9B9180F7178A18C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_4BFBE99FB9C4CE11DC99180F7178DE03_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_F5EEEF5F0296A0D6F9B9180F7178A18C" xlink:to="loc_us-gaap_RelatedPartyDomain_4BFBE99FB9C4CE11DC99180F7178DE03_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_4BFBE99FB9C4CE11DC99180F7178DE03" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_F5EEEF5F0296A0D6F9B9180F7178A18C" xlink:to="loc_us-gaap_RelatedPartyDomain_4BFBE99FB9C4CE11DC99180F7178DE03" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_541039CD93548D0C427F180F71799780" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_FBADA8C9FE3E3756EA88180F7178283E" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_541039CD93548D0C427F180F71799780" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_40D273FC76ABE4A39D71180F717974EC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_541039CD93548D0C427F180F71799780" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_40D273FC76ABE4A39D71180F717974EC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_40D273FC76ABE4A39D71180F717974EC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_541039CD93548D0C427F180F71799780" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_40D273FC76ABE4A39D71180F717974EC" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_OperationsandMaintenanceservicesMember" xlink:label="loc_nrg_OperationsandMaintenanceservicesMember_00F9E24E5AC22CA7D5B8180F717FF24F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_40D273FC76ABE4A39D71180F717974EC" xlink:to="loc_nrg_OperationsandMaintenanceservicesMember_00F9E24E5AC22CA7D5B8180F717FF24F" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/SegmentReporting" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/SegmentReportingDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_8A28A5AFA56C02EF76B31C5C2CC0F37B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_A0794B7CCAA5F493F2171C5C2CB9564A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8A28A5AFA56C02EF76B31C5C2CC0F37B" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_A0794B7CCAA5F493F2171C5C2CB9564A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_DE49DF90A16B7898FBC61C5C2CB9EA91" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_A0794B7CCAA5F493F2171C5C2CB9564A" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_DE49DF90A16B7898FBC61C5C2CB9EA91" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_5CA0EC3664B9DCFE63F91C5C2CBF5432_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_DE49DF90A16B7898FBC61C5C2CB9EA91" xlink:to="loc_us-gaap_SegmentDomain_5CA0EC3664B9DCFE63F91C5C2CBF5432_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_5CA0EC3664B9DCFE63F91C5C2CBF5432" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_DE49DF90A16B7898FBC61C5C2CB9EA91" xlink:to="loc_us-gaap_SegmentDomain_5CA0EC3664B9DCFE63F91C5C2CBF5432" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ConventionalGenerationMember" xlink:label="loc_nrg_ConventionalGenerationMember_0A6A2DDAED41F453AE2F1C5C2CBFB9F0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5CA0EC3664B9DCFE63F91C5C2CBF5432" xlink:to="loc_nrg_ConventionalGenerationMember_0A6A2DDAED41F453AE2F1C5C2CBFB9F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateMember" xlink:label="loc_us-gaap_CorporateMember_956262CA207D90AEA38C1C5C2CC0FF12" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5CA0EC3664B9DCFE63F91C5C2CBF5432" xlink:to="loc_us-gaap_CorporateMember_956262CA207D90AEA38C1C5C2CC0FF12" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ThermalMember" xlink:label="loc_nrg_ThermalMember_5B7B5F4D7739C6968B5F1C5C2CC001FF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5CA0EC3664B9DCFE63F91C5C2CBF5432" xlink:to="loc_nrg_ThermalMember_5B7B5F4D7739C6968B5F1C5C2CC001FF" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_RenewablesMember" xlink:label="loc_nrg_RenewablesMember_36D37884E3175621C67D1C5C2CC0FFFF" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5CA0EC3664B9DCFE63F91C5C2CBF5432" xlink:to="loc_nrg_RenewablesMember_36D37884E3175621C67D1C5C2CC0FFFF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_22FC286E6872CB15571D1C5C2CC16C9D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8A28A5AFA56C02EF76B31C5C2CC0F37B" xlink:to="loc_us-gaap_Revenues_22FC286E6872CB15571D1C5C2CC16C9D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaap_OperatingExpenses_54D534561D4F3881B3531C5C2CC12C0B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8A28A5AFA56C02EF76B31C5C2CC0F37B" xlink:to="loc_us-gaap_OperatingExpenses_54D534561D4F3881B3531C5C2CC12C0B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_930AB125019310FD853B1C5C2CC17D08" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8A28A5AFA56C02EF76B31C5C2CC0F37B" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_930AB125019310FD853B1C5C2CC17D08" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_B89181216DB66D0E17CD1C5C2CC132A3" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8A28A5AFA56C02EF76B31C5C2CC0F37B" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_B89181216DB66D0E17CD1C5C2CC132A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_E4164D9D5A0E562AEC6D1C5C2CC1EF9B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8A28A5AFA56C02EF76B31C5C2CC0F37B" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_E4164D9D5A0E562AEC6D1C5C2CC1EF9B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_E6FA020AD8A10AD4E26A1C5C2CC1191F" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8A28A5AFA56C02EF76B31C5C2CC0F37B" xlink:to="loc_us-gaap_OperatingIncomeLoss_E6FA020AD8A10AD4E26A1C5C2CC1191F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_27AB491975D49D3DA6F61C5C2CC1E7D0" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8A28A5AFA56C02EF76B31C5C2CC0F37B" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_27AB491975D49D3DA6F61C5C2CC1E7D0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_9390F9C88B943D44AAF21C5C2CC173AB" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8A28A5AFA56C02EF76B31C5C2CC0F37B" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_9390F9C88B943D44AAF21C5C2CC173AB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_D67A429A681C0E93E9671C5C2CC182CA" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8A28A5AFA56C02EF76B31C5C2CC0F37B" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_D67A429A681C0E93E9671C5C2CC182CA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_3575996EB0BD377485421C5C2CC2F073" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8A28A5AFA56C02EF76B31C5C2CC0F37B" xlink:to="loc_us-gaap_InterestExpense_3575996EB0BD377485421C5C2CC2F073" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_5EE38E2BF532FEC275951C5C2CC21E45" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8A28A5AFA56C02EF76B31C5C2CC0F37B" xlink:to="loc_us-gaap_ProfitLoss_5EE38E2BF532FEC275951C5C2CC21E45" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_963A62219BA5416CA2C51C5C2CC202E0" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_8A28A5AFA56C02EF76B31C5C2CC0F37B" xlink:to="loc_us-gaap_Assets_963A62219BA5416CA2C51C5C2CC202E0" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/SegmentReportingSegmentReportingPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/SegmentReportingTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/SummaryOfSignificantAccountingPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/SummaryOfSignificantAccountingPoliciesDetails" xlink:type="extended">
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SummaryOfSignificantAccountingPoliciesLineItems" xlink:label="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:type="locator" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SummaryofSignificantAccountingPoliciesTable" xlink:label="loc_nrg_SummaryofSignificantAccountingPoliciesTable_AC6588BAC9CD33ABF51D0741D7DA774C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_nrg_SummaryofSignificantAccountingPoliciesTable_AC6588BAC9CD33ABF51D0741D7DA774C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_278ABA49407E80ADAB460741D7DADD61" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_SummaryofSignificantAccountingPoliciesTable_AC6588BAC9CD33ABF51D0741D7DA774C" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_278ABA49407E80ADAB460741D7DADD61" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ReceivableTypeDomain" xlink:label="loc_us-gaap_ReceivableTypeDomain_121FE4178EACA0ED0C94076B51D706DD_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_278ABA49407E80ADAB460741D7DADD61" xlink:to="loc_us-gaap_ReceivableTypeDomain_121FE4178EACA0ED0C94076B51D706DD_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ReceivableTypeDomain" xlink:label="loc_us-gaap_ReceivableTypeDomain_121FE4178EACA0ED0C94076B51D706DD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_278ABA49407E80ADAB460741D7DADD61" xlink:to="loc_us-gaap_ReceivableTypeDomain_121FE4178EACA0ED0C94076B51D706DD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LeaseAgreementsMember" xlink:label="loc_us-gaap_LeaseAgreementsMember_D53F53396F8D27C4FA650741D7DA5D4F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_121FE4178EACA0ED0C94076B51D706DD" xlink:to="loc_us-gaap_LeaseAgreementsMember_D53F53396F8D27C4FA650741D7DA5D4F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CustomerContractsMember" xlink:label="loc_us-gaap_CustomerContractsMember_7A03C08056000833C0270741D7DA8BF8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_121FE4178EACA0ED0C94076B51D706DD" xlink:to="loc_us-gaap_CustomerContractsMember_7A03C08056000833C0270741D7DA8BF8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="loc_us-gaap_ProductOrServiceAxis_CB2FEF7EF4529AE8A0170741D7DA6DD4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_SummaryofSignificantAccountingPoliciesTable_AC6588BAC9CD33ABF51D0741D7DA774C" xlink:to="loc_us-gaap_ProductOrServiceAxis_CB2FEF7EF4529AE8A0170741D7DA6DD4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_8E9EB505500E998A9E53076BA9C4A596_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ProductOrServiceAxis_CB2FEF7EF4529AE8A0170741D7DA6DD4" xlink:to="loc_us-gaap_ProductsAndServicesDomain_8E9EB505500E998A9E53076BA9C4A596_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_8E9EB505500E998A9E53076BA9C4A596" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ProductOrServiceAxis_CB2FEF7EF4529AE8A0170741D7DA6DD4" xlink:to="loc_us-gaap_ProductsAndServicesDomain_8E9EB505500E998A9E53076BA9C4A596" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_EnergyRevenueMember" xlink:label="loc_nrg_EnergyRevenueMember_52BC5F6C4E019D1942C20741D7DB78F4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductsAndServicesDomain_8E9EB505500E998A9E53076BA9C4A596" xlink:to="loc_nrg_EnergyRevenueMember_52BC5F6C4E019D1942C20741D7DB78F4" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_CapacityRevenueMember" xlink:label="loc_nrg_CapacityRevenueMember_A4FA7142A5ADAC5583B20741D7DB11C0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductsAndServicesDomain_8E9EB505500E998A9E53076BA9C4A596" xlink:to="loc_nrg_CapacityRevenueMember_A4FA7142A5ADAC5583B20741D7DB11C0" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ProductsAndServicesOtherMember" xlink:label="loc_nrg_ProductsAndServicesOtherMember_68919394A69333CCD3520741D7DB0FF1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductsAndServicesDomain_8E9EB505500E998A9E53076BA9C4A596" xlink:to="loc_nrg_ProductsAndServicesOtherMember_68919394A69333CCD3520741D7DB0FF1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_206E6585768517D45D100741D7DBD4FB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_SummaryofSignificantAccountingPoliciesTable_AC6588BAC9CD33ABF51D0741D7DA774C" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_206E6585768517D45D100741D7DBD4FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_EF5FAC0FEF44C52B78630741D7DBDEA6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_206E6585768517D45D100741D7DBD4FB" xlink:to="loc_us-gaap_SegmentDomain_EF5FAC0FEF44C52B78630741D7DBDEA6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_EF5FAC0FEF44C52B78630741D7DBDEA6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_206E6585768517D45D100741D7DBD4FB" xlink:to="loc_us-gaap_SegmentDomain_EF5FAC0FEF44C52B78630741D7DBDEA6" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ConventionalGenerationMember" xlink:label="loc_nrg_ConventionalGenerationMember_D57B40349F947CAC72EB0741D7DB4DAD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_EF5FAC0FEF44C52B78630741D7DBDEA6" xlink:to="loc_nrg_ConventionalGenerationMember_D57B40349F947CAC72EB0741D7DB4DAD" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_RenewablesMember" xlink:label="loc_nrg_RenewablesMember_6AE13A3BBE07D87A7F5C0741D7DB18DF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_EF5FAC0FEF44C52B78630741D7DBDEA6" xlink:to="loc_nrg_RenewablesMember_6AE13A3BBE07D87A7F5C0741D7DB18DF" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ThermalMember" xlink:label="loc_nrg_ThermalMember_7B73225AE7A828AB64840741D7DB8A1E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_EF5FAC0FEF44C52B78630741D7DBDEA6" xlink:to="loc_nrg_ThermalMember_7B73225AE7A828AB64840741D7DB8A1E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_91232EC6DA17A43FC8CC0741D7DB36E9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_SummaryofSignificantAccountingPoliciesTable_AC6588BAC9CD33ABF51D0741D7DA774C" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_91232EC6DA17A43FC8CC0741D7DB36E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_2E8A91F9FC51DD1E61DB0741D7DB87AC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_91232EC6DA17A43FC8CC0741D7DB36E9" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_2E8A91F9FC51DD1E61DB0741D7DB87AC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_2E8A91F9FC51DD1E61DB0741D7DB87AC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_91232EC6DA17A43FC8CC0741D7DB36E9" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_2E8A91F9FC51DD1E61DB0741D7DB87AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_97CA10335687713D63460741D7DBCD48" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_2E8A91F9FC51DD1E61DB0741D7DB87AC" xlink:to="loc_us-gaap_SubsequentEventMember_97CA10335687713D63460741D7DBCD48" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_F00658916DFBD28994D50741D7DBEEEF" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_SummaryofSignificantAccountingPoliciesTable_AC6588BAC9CD33ABF51D0741D7DA774C" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_F00658916DFBD28994D50741D7DBEEEF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_E108B06A84E9513F38550741D7DB7692_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_F00658916DFBD28994D50741D7DBEEEF" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_E108B06A84E9513F38550741D7DB7692_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_E108B06A84E9513F38550741D7DB7692" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_F00658916DFBD28994D50741D7DBEEEF" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_E108B06A84E9513F38550741D7DB7692" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_August2017DropDownAssetsMember" xlink:label="loc_nrg_August2017DropDownAssetsMember_F4809836B2785CEB0B380741D7DCBC70" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E108B06A84E9513F38550741D7DB7692" xlink:to="loc_nrg_August2017DropDownAssetsMember_F4809836B2785CEB0B380741D7DCBC70" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_8C78EA8F577BA9D4660D0741D7DC23D5" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_SummaryofSignificantAccountingPoliciesTable_AC6588BAC9CD33ABF51D0741D7DA774C" xlink:to="loc_us-gaap_StatementScenarioAxis_8C78EA8F577BA9D4660D0741D7DC23D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_4A77D2A62CA330B6599D0741D7DC8C3A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_8C78EA8F577BA9D4660D0741D7DC23D5" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_4A77D2A62CA330B6599D0741D7DC8C3A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_4A77D2A62CA330B6599D0741D7DC8C3A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_8C78EA8F577BA9D4660D0741D7DC23D5" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_4A77D2A62CA330B6599D0741D7DC8C3A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioPreviouslyReportedMember" xlink:label="loc_us-gaap_ScenarioPreviouslyReportedMember_C9993BF55319B5BC16960741D7DCF890" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScenarioUnspecifiedDomain_4A77D2A62CA330B6599D0741D7DC8C3A" xlink:to="loc_us-gaap_ScenarioPreviouslyReportedMember_C9993BF55319B5BC16960741D7DCF890" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_F7BFA5FA5AC2A7FF27730741D7DCBD5F" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_SummaryofSignificantAccountingPoliciesTable_AC6588BAC9CD33ABF51D0741D7DA774C" xlink:to="loc_us-gaap_StatementClassOfStockAxis_F7BFA5FA5AC2A7FF27730741D7DCBD5F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_146E9B587B176A4231890741D7DCB6FC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_F7BFA5FA5AC2A7FF27730741D7DCBD5F" xlink:to="loc_us-gaap_ClassOfStockDomain_146E9B587B176A4231890741D7DCB6FC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_146E9B587B176A4231890741D7DCB6FC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_F7BFA5FA5AC2A7FF27730741D7DCBD5F" xlink:to="loc_us-gaap_ClassOfStockDomain_146E9B587B176A4231890741D7DCB6FC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember_76D4D713254ABE8550CB0741D7DCD182" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_146E9B587B176A4231890741D7DCB6FC" xlink:to="loc_us-gaap_CommonClassAMember_76D4D713254ABE8550CB0741D7DCD182" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonClassCMember" xlink:label="loc_us-gaap_CommonClassCMember_481460588F620DA1CDBD0741D7DC38D8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_146E9B587B176A4231890741D7DCB6FC" xlink:to="loc_us-gaap_CommonClassCMember_481460588F620DA1CDBD0741D7DC38D8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_9AC1AAF3BE7D4D290B6F0741D7DDD30D" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_SummaryofSignificantAccountingPoliciesTable_AC6588BAC9CD33ABF51D0741D7DA774C" xlink:to="loc_dei_LegalEntityAxis_9AC1AAF3BE7D4D290B6F0741D7DDD30D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_6B944D369EB732E0C4290741D7DD675F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_9AC1AAF3BE7D4D290B6F0741D7DDD30D" xlink:to="loc_dei_EntityDomain_6B944D369EB732E0C4290741D7DD675F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_6B944D369EB732E0C4290741D7DD675F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_9AC1AAF3BE7D4D290B6F0741D7DDD30D" xlink:to="loc_dei_EntityDomain_6B944D369EB732E0C4290741D7DD675F" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NrgYieldIncMember" xlink:label="loc_nrg_NrgYieldIncMember_584D0B85BF1AB4E08F770741D7DD113B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_6B944D369EB732E0C4290741D7DD675F" xlink:to="loc_nrg_NrgYieldIncMember_584D0B85BF1AB4E08F770741D7DD113B" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_November2015DropDownAssetsMember" xlink:label="loc_nrg_November2015DropDownAssetsMember_641B919AE0C11248B2350741D7DD4C14" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_6B944D369EB732E0C4290741D7DD675F" xlink:to="loc_nrg_November2015DropDownAssetsMember_641B919AE0C11248B2350741D7DD4C14" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AltaXandXITEHoldcoMember" xlink:label="loc_nrg_AltaXandXITEHoldcoMember_2069139B537AE38C0A350741D7DDE138" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_6B944D369EB732E0C4290741D7DD675F" xlink:to="loc_nrg_AltaXandXITEHoldcoMember_2069139B537AE38C0A350741D7DDE138" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SpringCanyonMember" xlink:label="loc_nrg_SpringCanyonMember_9D00D895F79287F51DC70741D7DD3C54" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_6B944D369EB732E0C4290741D7DD675F" xlink:to="loc_nrg_SpringCanyonMember_9D00D895F79287F51DC70741D7DD3C54" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationFacilitiesByTypeAxis" xlink:label="loc_nrg_PowerGenerationFacilitiesByTypeAxis_744B6732F39ABC48CDF40741D7DD8C48" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_SummaryofSignificantAccountingPoliciesTable_AC6588BAC9CD33ABF51D0741D7DA774C" xlink:to="loc_nrg_PowerGenerationFacilitiesByTypeAxis_744B6732F39ABC48CDF40741D7DD8C48" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationFacilitiesTypeDomain" xlink:label="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC2E04F30434B8DA07610741D7DDE5AA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_nrg_PowerGenerationFacilitiesByTypeAxis_744B6732F39ABC48CDF40741D7DD8C48" xlink:to="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC2E04F30434B8DA07610741D7DDE5AA_default" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationFacilitiesTypeDomain" xlink:label="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC2E04F30434B8DA07610741D7DDE5AA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_nrg_PowerGenerationFacilitiesByTypeAxis_744B6732F39ABC48CDF40741D7DD8C48" xlink:to="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC2E04F30434B8DA07610741D7DDE5AA" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_WindFarmsMember" xlink:label="loc_nrg_WindFarmsMember_EF28FB1AEFD32136F92F0741D7DE1065" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_PowerGenerationFacilitiesTypeDomain_BC2E04F30434B8DA07610741D7DDE5AA" xlink:to="loc_nrg_WindFarmsMember_EF28FB1AEFD32136F92F0741D7DE1065" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherOwnershipInterestsByNameAxis" xlink:label="loc_us-gaap_OtherOwnershipInterestsByNameAxis_537160A90B7E45FA29590741D7DE6930" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_SummaryofSignificantAccountingPoliciesTable_AC6588BAC9CD33ABF51D0741D7DA774C" xlink:to="loc_us-gaap_OtherOwnershipInterestsByNameAxis_537160A90B7E45FA29590741D7DE6930" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherOwnershipInterestsNameDomain" xlink:label="loc_us-gaap_OtherOwnershipInterestsNameDomain_C76D5E5B0FBBA6E9F9690741D7DE27A8_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherOwnershipInterestsByNameAxis_537160A90B7E45FA29590741D7DE6930" xlink:to="loc_us-gaap_OtherOwnershipInterestsNameDomain_C76D5E5B0FBBA6E9F9690741D7DE27A8_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherOwnershipInterestsNameDomain" xlink:label="loc_us-gaap_OtherOwnershipInterestsNameDomain_C76D5E5B0FBBA6E9F9690741D7DE27A8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherOwnershipInterestsByNameAxis_537160A90B7E45FA29590741D7DE6930" xlink:to="loc_us-gaap_OtherOwnershipInterestsNameDomain_C76D5E5B0FBBA6E9F9690741D7DE27A8" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_FinancialInstitutionsMember" xlink:label="loc_nrg_FinancialInstitutionsMember_C37E23F74DA6855809360741D7DE9DB1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherOwnershipInterestsNameDomain_C76D5E5B0FBBA6E9F9690741D7DE27A8" xlink:to="loc_nrg_FinancialInstitutionsMember_C37E23F74DA6855809360741D7DE9DB1" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SpringCanyonMember" xlink:label="loc_nrg_SpringCanyonMember_5B5BFA71F6649FFAFA960741D7DE0841" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherOwnershipInterestsNameDomain_C76D5E5B0FBBA6E9F9690741D7DE27A8" xlink:to="loc_nrg_SpringCanyonMember_5B5BFA71F6649FFAFA960741D7DE0841" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_C17B60D3AB66E0D2EA5B0741D7DEDBCA" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_nrg_SummaryofSignificantAccountingPoliciesTable_AC6588BAC9CD33ABF51D0741D7DA774C" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_C17B60D3AB66E0D2EA5B0741D7DEDBCA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_AA4AED8F146979CC550C0741D7DE8126_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_C17B60D3AB66E0D2EA5B0741D7DEDBCA" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_AA4AED8F146979CC550C0741D7DE8126_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_AA4AED8F146979CC550C0741D7DE8126" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_C17B60D3AB66E0D2EA5B0741D7DEDBCA" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_AA4AED8F146979CC550C0741D7DE8126" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SpringCanyonMember" xlink:label="loc_nrg_SpringCanyonMember_09ADCB4B81E61EBEB8740741D7DFA231" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_AA4AED8F146979CC550C0741D7DE8126" xlink:to="loc_nrg_SpringCanyonMember_09ADCB4B81E61EBEB8740741D7DFA231" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNet" xlink:label="loc_us-gaap_AccountsReceivableNet_65010BA79BD6C3E8F5FA0741D7DF00E5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_AccountsReceivableNet_65010BA79BD6C3E8F5FA0741D7DF00E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_84B0603434F60439E2580741D7DF47A4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_84B0603434F60439E2580741D7DF47A4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CapitalizedContractCostAmortization" xlink:label="loc_us-gaap_CapitalizedContractCostAmortization_44D6E019370A67CDCAF90741D7DF34F3" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_CapitalizedContractCostAmortization_44D6E019370A67CDCAF90741D7DF34F3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_750107B90D9447658C6E0741D7DFAE23" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_Revenues_750107B90D9447658C6E0741D7DFAE23" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasesIncomeStatementContingentRevenue" xlink:label="loc_us-gaap_OperatingLeasesIncomeStatementContingentRevenue_36F5EEC79484AE0CD56E0741D7DF02DC" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_OperatingLeasesIncomeStatementContingentRevenue_36F5EEC79484AE0CD56E0741D7DF02DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MembersEquityAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_MembersEquityAttributableToNoncontrollingInterest_8A9C8657F38627B8CD340741D7DF1C62" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_MembersEquityAttributableToNoncontrollingInterest_8A9C8657F38627B8CD340741D7DF1C62" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_5FB412AB6EA18B1229250741D7DFE780" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_5FB412AB6EA18B1229250741D7DFE780" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_BB86AA692192E9C5131F0741D7DFED6A" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_BB86AA692192E9C5131F0741D7DFED6A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinorityInterest" xlink:label="loc_us-gaap_MinorityInterest_00297F2D4C1F748B0B030741D7DF190F" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_MinorityInterest_00297F2D4C1F748B0B030741D7DF190F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromMinorityShareholders" xlink:label="loc_us-gaap_ProceedsFromMinorityShareholders_86AC7DD392CB6BFE4E600741D7DF9A67" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_ProceedsFromMinorityShareholders_86AC7DD392CB6BFE4E600741D7DF9A67" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsOfCapitalDistribution" xlink:label="loc_us-gaap_PaymentsOfCapitalDistribution_23E6E57AE83261E34D560741D7E01312" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_PaymentsOfCapitalDistribution_23E6E57AE83261E34D560741D7E01312" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest_EEC575C139D8F1101BF80741D7E0C8BB" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest_EEC575C139D8F1101BF80741D7E0C8BB" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PercentageOfOwnership" xlink:label="loc_nrg_PercentageOfOwnership_71D1F95BF025E018ED7C0741D7E0A229" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_nrg_PercentageOfOwnership_71D1F95BF025E018ED7C0741D7E0A229" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DividendsPayableDateDeclaredDayMonthAndYear" xlink:label="loc_us-gaap_DividendsPayableDateDeclaredDayMonthAndYear_46ED5AD6FA3F8865118A0741D7E0EB3C" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_DividendsPayableDateDeclaredDayMonthAndYear_46ED5AD6FA3F8865118A0741D7E0EB3C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockDividendsPerShareDeclared" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_D5D7A2DF2E87BFBC18F00741D7E05393" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_D5D7A2DF2E87BFBC18F00741D7E05393" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DividendPayableDateToBePaidDayMonthAndYear" xlink:label="loc_us-gaap_DividendPayableDateToBePaidDayMonthAndYear_0A8BB8CEB2977C211B830741D7E0FBF2" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_DividendPayableDateToBePaidDayMonthAndYear_0A8BB8CEB2977C211B830741D7E0FBF2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DividendsPayableDateOfRecordDayMonthAndYear" xlink:label="loc_us-gaap_DividendsPayableDateOfRecordDayMonthAndYear_743E08E644392FE8AFCD0741D7E04B1F" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_DividendsPayableDateOfRecordDayMonthAndYear_743E08E644392FE8AFCD0741D7E04B1F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_D7C04584183305E8E5C20741D7E0E045" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_D7C04584183305E8E5C20741D7E0E045" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ATMProgramMaximumDollarValueofSharestoBeIssued" xlink:label="loc_nrg_ATMProgramMaximumDollarValueofSharestoBeIssued_903FCA7DC4D95213E5660741D7E083A7" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_nrg_ATMProgramMaximumDollarValueofSharestoBeIssued_903FCA7DC4D95213E5660741D7E083A7" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ProceedsfromIssuanceofCommonStockBeforeCommissionFees" xlink:label="loc_nrg_ProceedsfromIssuanceofCommonStockBeforeCommissionFees_1A7F8BDA1CDA7408C4670741D7E0DD73" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_nrg_ProceedsfromIssuanceofCommonStockBeforeCommissionFees_1A7F8BDA1CDA7408C4670741D7E0DD73" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockDividendsPerShareCashPaid" xlink:label="loc_us-gaap_CommonStockDividendsPerShareCashPaid_3522DAA2DA24FDD071780741D7E015B4" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_CommonStockDividendsPerShareCashPaid_3522DAA2DA24FDD071780741D7E015B4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_FA72ABE982D2672E5CA20741D7E04643" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_FA72ABE982D2672E5CA20741D7E04643" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_25C22F748ADD5FD5DE4B0741D7E05CF1" xlink:type="locator" />
    <link:definitionArc order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_25C22F748ADD5FD5DE4B0741D7E05CF1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" xlink:label="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_D5ABA1EC40E666B04F3A0741D7E1EB56" xlink:type="locator" />
    <link:definitionArc order="24" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_D5ABA1EC40E666B04F3A0741D7E1EB56" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_C72F441B54A0318046410741D7E1E8B6" xlink:type="locator" />
    <link:definitionArc order="25" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_C72F441B54A0318046410741D7E1E8B6" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ATMprogramdollarvalueofsharesremaining" xlink:label="loc_nrg_ATMprogramdollarvalueofsharesremaining_405E6A6FFD1B10509DA30741D7E10BFF" xlink:type="locator" />
    <link:definitionArc order="26" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_nrg_SummaryOfSignificantAccountingPoliciesLineItems_8CFC45DF91094CCE189B0741D7DFEB01" xlink:to="loc_nrg_ATMprogramdollarvalueofsharesremaining_405E6A6FFD1B10509DA30741D7E10BFF" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/SummaryOfSignificantAccountingPoliciesSummaryOfSignificantAccountingPoliciesPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/SummaryOfSignificantAccountingPoliciesSummaryOfSignificantAccountingPoliciesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/VariableInterestEntities" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/VariableInterestEntitiesTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_147B313976FD364A35DEFD65C512AA44" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_9846034AA0C1E16ED9F0FD65C512E41B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_147B313976FD364A35DEFD65C512AA44" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_9846034AA0C1E16ED9F0FD65C512E41B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_F9B48A0102120B6A777DFD65C512060B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_9846034AA0C1E16ED9F0FD65C512E41B" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_F9B48A0102120B6A777DFD65C512060B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_C17AD9FE94C508E4034DFD65C5129426_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_F9B48A0102120B6A777DFD65C512060B" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_C17AD9FE94C508E4034DFD65C5129426_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_C17AD9FE94C508E4034DFD65C5129426" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_F9B48A0102120B6A777DFD65C512060B" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_C17AD9FE94C508E4034DFD65C5129426" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesMember" xlink:label="loc_us-gaap_ConsolidatedEntitiesMember_D5701C05C4177A4A6C7EFD65C512DACE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_C17AD9FE94C508E4034DFD65C5129426" xlink:to="loc_us-gaap_ConsolidatedEntitiesMember_D5701C05C4177A4A6C7EFD65C512DACE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E187FC32C9D38C6F3A1FFD65C512BCD6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_9846034AA0C1E16ED9F0FD65C512E41B" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E187FC32C9D38C6F3A1FFD65C512BCD6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_22895B2A0F96073C0A22FD65C51260B6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E187FC32C9D38C6F3A1FFD65C512BCD6" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_22895B2A0F96073C0A22FD65C51260B6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_22895B2A0F96073C0A22FD65C51260B6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_E187FC32C9D38C6F3A1FFD65C512BCD6" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_22895B2A0F96073C0A22FD65C51260B6" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_March2017DropDownAssetsMember" xlink:label="loc_nrg_March2017DropDownAssetsMember_0D93F035E81EF23ECBCBFD65C512CE58" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_22895B2A0F96073C0A22FD65C51260B6" xlink:to="loc_nrg_March2017DropDownAssetsMember_0D93F035E81EF23ECBCBFD65C512CE58" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_EntitiesthatarenotconsolidatedMember" xlink:label="loc_nrg_EntitiesthatarenotconsolidatedMember_51616CCEAF1A926E256DFD65C51211A4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_22895B2A0F96073C0A22FD65C51260B6" xlink:to="loc_nrg_EntitiesthatarenotconsolidatedMember_51616CCEAF1A926E256DFD65C51211A4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestmentsTextBlock" xlink:label="loc_us-gaap_EquityMethodInvestmentsTextBlock_3090EBBDE2D6A1F6FDF1FD65C5121820" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_147B313976FD364A35DEFD65C512AA44" xlink:to="loc_us-gaap_EquityMethodInvestmentsTextBlock_3090EBBDE2D6A1F6FDF1FD65C5121820" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTextBlock" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTextBlock_5B8EDDFE17CC439FEA82FD65C512DD19" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_147B313976FD364A35DEFD65C512AA44" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTextBlock_5B8EDDFE17CC439FEA82FD65C512DD19" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/VariableInterestEntitiesVariableInterestEntitiesConsolidatedEntitiesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_44F0E16008C2BF0D2A8E0741D78EEEA7" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_696ECB7CF1A5BB37D4BF0741D78D6D08" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_44F0E16008C2BF0D2A8E0741D78EEEA7" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_696ECB7CF1A5BB37D4BF0741D78D6D08" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_060ED4CD55714BDC9F8C07AE97865B3E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_696ECB7CF1A5BB37D4BF0741D78D6D08" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_060ED4CD55714BDC9F8C07AE97865B3E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_B85726B6230B52F1062D07AE978B1719_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_060ED4CD55714BDC9F8C07AE97865B3E" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_B85726B6230B52F1062D07AE978B1719_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_B85726B6230B52F1062D07AE978B1719" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_060ED4CD55714BDC9F8C07AE97865B3E" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_B85726B6230B52F1062D07AE978B1719" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BuckthornSolarDropDownAssetMember" xlink:label="loc_nrg_BuckthornSolarDropDownAssetMember_77E0BCE3643851CB0AAB07AE97D207A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_B85726B6230B52F1062D07AE978B1719" xlink:to="loc_nrg_BuckthornSolarDropDownAssetMember_77E0BCE3643851CB0AAB07AE97D207A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_8ED9DE0F2F70CF81E9290741D78E3940" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_696ECB7CF1A5BB37D4BF0741D78D6D08" xlink:to="loc_dei_LegalEntityAxis_8ED9DE0F2F70CF81E9290741D78E3940" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_F6FC6D9CF865917CB0C90741D78EED23_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_8ED9DE0F2F70CF81E9290741D78E3940" xlink:to="loc_dei_EntityDomain_F6FC6D9CF865917CB0C90741D78EED23_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_F6FC6D9CF865917CB0C90741D78EED23" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_8ED9DE0F2F70CF81E9290741D78E3940" xlink:to="loc_dei_EntityDomain_F6FC6D9CF865917CB0C90741D78EED23" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_November2015DropDownAssetsMember" xlink:label="loc_nrg_November2015DropDownAssetsMember_880F80E96C4925E5D8F80741D78EFB2E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_F6FC6D9CF865917CB0C90741D78EED23" xlink:to="loc_nrg_November2015DropDownAssetsMember_880F80E96C4925E5D8F80741D78EFB2E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AltaXandXITEHoldcoMember" xlink:label="loc_nrg_AltaXandXITEHoldcoMember_5C4B3500054BC66DDF450741D78E2109" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_F6FC6D9CF865917CB0C90741D78EED23" xlink:to="loc_nrg_AltaXandXITEHoldcoMember_5C4B3500054BC66DDF450741D78E2109" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_SpringCanyonMember" xlink:label="loc_nrg_SpringCanyonMember_58E3FF574359E099175D0741D78E44AE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_F6FC6D9CF865917CB0C90741D78EED23" xlink:to="loc_nrg_SpringCanyonMember_58E3FF574359E099175D0741D78E44AE" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_BuckthornSolarDropDownAssetMember" xlink:label="loc_nrg_BuckthornSolarDropDownAssetMember_30B4D498CDF5E3E5EBF007AFB0802672" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_F6FC6D9CF865917CB0C90741D78EED23" xlink:to="loc_nrg_BuckthornSolarDropDownAssetMember_30B4D498CDF5E3E5EBF007AFB0802672" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationCapacityMegawatts" xlink:label="loc_nrg_PowerGenerationCapacityMegawatts_676322D040AEA6366BB107AE96C1E569" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_44F0E16008C2BF0D2A8E0741D78EEEA7" xlink:to="loc_nrg_PowerGenerationCapacityMegawatts_676322D040AEA6366BB107AE96C1E569" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssets" xlink:label="loc_us-gaap_OtherAssets_E6933C6D85595852ECF20741D78E6A34" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_44F0E16008C2BF0D2A8E0741D78EEEA7" xlink:to="loc_us-gaap_OtherAssets_E6933C6D85595852ECF20741D78E6A34" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_06B594851797E07A84EE0741D78E6B13" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_44F0E16008C2BF0D2A8E0741D78EEEA7" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_06B594851797E07A84EE0741D78E6B13" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_F7210EBE5AA1588077640741D78E96BE" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_44F0E16008C2BF0D2A8E0741D78EEEA7" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_F7210EBE5AA1588077640741D78E96BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_2BC8EC09B892E9D4F0DF0741D78EDB7C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_44F0E16008C2BF0D2A8E0741D78EEEA7" xlink:to="loc_us-gaap_Assets_2BC8EC09B892E9D4F0DF0741D78EDB7C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_15F2D5DD2F8EA8E78ACA0741D78EB75C" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_44F0E16008C2BF0D2A8E0741D78EEEA7" xlink:to="loc_us-gaap_Liabilities_15F2D5DD2F8EA8E78ACA0741D78EB75C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NoncontrollingInterestInVariableInterestEntity" xlink:label="loc_us-gaap_NoncontrollingInterestInVariableInterestEntity_98832B82C98D228140A30741D78E1917" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_44F0E16008C2BF0D2A8E0741D78EEEA7" xlink:to="loc_us-gaap_NoncontrollingInterestInVariableInterestEntity_98832B82C98D228140A30741D78E1917" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsNet" xlink:label="loc_us-gaap_AssetsNet_1ADADC94C759C36DCD4D0741D78E56F0" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_44F0E16008C2BF0D2A8E0741D78EEEA7" xlink:to="loc_us-gaap_AssetsNet_1ADADC94C759C36DCD4D0741D78E56F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_272E745008F74790C3C407AED32B3AB0" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_44F0E16008C2BF0D2A8E0741D78EEEA7" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_272E745008F74790C3C407AED32B3AB0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue_49A6C5526D599BDD0AC007AEFDEB8F74" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_44F0E16008C2BF0D2A8E0741D78EEEA7" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue_49A6C5526D599BDD0AC007AEFDEB8F74" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/VariableInterestEntitiesVariableInterestEntitiesDebtHeldByUnconsolidatedAffiliatesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_8C02C62C7AA7A9CFA4C81774BE53B509" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_CE1C653822CC0843749B1774BE50C56D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_8C02C62C7AA7A9CFA4C81774BE53B509" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_CE1C653822CC0843749B1774BE50C56D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeAxis" xlink:label="loc_us-gaap_InvestmentTypeAxis_C952D8633F0339C706EB1774BE5079A7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_CE1C653822CC0843749B1774BE50C56D" xlink:to="loc_us-gaap_InvestmentTypeAxis_C952D8633F0339C706EB1774BE5079A7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_6D3BB23DA54621F206CD1774BE50C77F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_C952D8633F0339C706EB1774BE5079A7" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_6D3BB23DA54621F206CD1774BE50C77F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_6D3BB23DA54621F206CD1774BE50C77F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_C952D8633F0339C706EB1774BE5079A7" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_6D3BB23DA54621F206CD1774BE50C77F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_ADCE5F16C0B65034C05D1774BE5169EA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_CE1C653822CC0843749B1774BE50C56D" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_ADCE5F16C0B65034C05D1774BE5169EA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_7716AB13B4361AA002701774BE51975C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_ADCE5F16C0B65034C05D1774BE5169EA" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_7716AB13B4361AA002701774BE51975C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_7716AB13B4361AA002701774BE51975C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_ADCE5F16C0B65034C05D1774BE5169EA" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_7716AB13B4361AA002701774BE51975C" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGDGPVHoldco2Member" xlink:label="loc_nrg_NRGDGPVHoldco2Member_3247339A629C43D0F1801774BE512C84" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_7716AB13B4361AA002701774BE51975C" xlink:to="loc_nrg_NRGDGPVHoldco2Member_3247339A629C43D0F1801774BE512C84" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AguaCalienteBorrower2Member" xlink:label="loc_nrg_AguaCalienteBorrower2Member_751E52A19C09F29794E61774BE5265D9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_7716AB13B4361AA002701774BE51975C" xlink:to="loc_nrg_AguaCalienteBorrower2Member_751E52A19C09F29794E61774BE5265D9" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_AguaCalienteMember" xlink:label="loc_nrg_AguaCalienteMember_5806D906950FE01279E31774BE528E27" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_7716AB13B4361AA002701774BE51975C" xlink:to="loc_nrg_AguaCalienteMember_5806D906950FE01279E31774BE528E27" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupClassificationAxis" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_0D7607822FB4E904F2121774BE5298B5" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_CE1C653822CC0843749B1774BE50C56D" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_0D7607822FB4E904F2121774BE5298B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_B8C29F206FF29E93C78B1774BE5284C2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_0D7607822FB4E904F2121774BE5298B5" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_B8C29F206FF29E93C78B1774BE5284C2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_B8C29F206FF29E93C78B1774BE5284C2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_0D7607822FB4E904F2121774BE5298B5" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_B8C29F206FF29E93C78B1774BE5284C2" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationCapacityMegawatts" xlink:label="loc_nrg_PowerGenerationCapacityMegawatts_9FCD2A20C889336AF1C71774BE539FFE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_8C02C62C7AA7A9CFA4C81774BE53B509" xlink:to="loc_nrg_PowerGenerationCapacityMegawatts_9FCD2A20C889336AF1C71774BE539FFE" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_RemainingLeaseTerm" xlink:label="loc_nrg_RemainingLeaseTerm_5CD6A1DE21D0C9192CDE1774BE537979" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_8C02C62C7AA7A9CFA4C81774BE53B509" xlink:to="loc_nrg_RemainingLeaseTerm_5CD6A1DE21D0C9192CDE1774BE537979" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_ProRateShareofDebtHeldbyUnconsolidatedAffiliates" xlink:label="loc_nrg_ProRateShareofDebtHeldbyUnconsolidatedAffiliates_9E87D72763B35656CE9E1774BE537D53" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_8C02C62C7AA7A9CFA4C81774BE53B509" xlink:to="loc_nrg_ProRateShareofDebtHeldbyUnconsolidatedAffiliates_9E87D72763B35656CE9E1774BE537D53" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_FABF200022E6F07154811774BE53F6DA" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_8C02C62C7AA7A9CFA4C81774BE53B509" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_FABF200022E6F07154811774BE53F6DA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_DD8A9CE33D7AAA15E9CD1774BE536597" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_8C02C62C7AA7A9CFA4C81774BE53B509" xlink:to="loc_us-gaap_LongTermDebt_DD8A9CE33D7AAA15E9CD1774BE536597" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_DebtInstrumentBasisSpreadOnLiborRate" xlink:label="loc_nrg_DebtInstrumentBasisSpreadOnLiborRate_20C1A53ED8E8F017E6371774BE539595" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_8C02C62C7AA7A9CFA4C81774BE53B509" xlink:to="loc_nrg_DebtInstrumentBasisSpreadOnLiborRate_20C1A53ED8E8F017E6371774BE539595" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/VariableInterestEntitiesVariableInterestEntitiesUnconsolidatedEntitiesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_497DCE9132538936FBB91776C41D7A83" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_497DCE9132538936FBB91776C41D7A83" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_9EE25E7E6CF56F8322671776C41D5DAC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_497DCE9132538936FBB91776C41D7A83" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_9EE25E7E6CF56F8322671776C41D5DAC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_3DA9E85CCE037B3485141776C41D926E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_9EE25E7E6CF56F8322671776C41D5DAC" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_3DA9E85CCE037B3485141776C41D926E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_3DA9E85CCE037B3485141776C41D926E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_9EE25E7E6CF56F8322671776C41D5DAC" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_3DA9E85CCE037B3485141776C41D926E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_7DAAFD7424E36BB667AB1776C41D91E5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_3DA9E85CCE037B3485141776C41D926E" xlink:to="loc_us-gaap_SubsequentEventMember_7DAAFD7424E36BB667AB1776C41D91E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeAxis" xlink:label="loc_us-gaap_InvestmentTypeAxis_5293C1E5CB5BCA75162D1776C41E8EE0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_497DCE9132538936FBB91776C41D7A83" xlink:to="loc_us-gaap_InvestmentTypeAxis_5293C1E5CB5BCA75162D1776C41E8EE0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_EF96D16E4C06DC3F75651776C41E60A3_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_5293C1E5CB5BCA75162D1776C41E8EE0" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_EF96D16E4C06DC3F75651776C41E60A3_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_EF96D16E4C06DC3F75651776C41E60A3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_5293C1E5CB5BCA75162D1776C41E8EE0" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_EF96D16E4C06DC3F75651776C41E60A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_F34271FBB20071A925131776C41E1AC4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_497DCE9132538936FBB91776C41D7A83" xlink:to="loc_us-gaap_RangeAxis_F34271FBB20071A925131776C41E1AC4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_3AC6FD2709E4C38F55BC1776C41E2CA9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_F34271FBB20071A925131776C41E1AC4" xlink:to="loc_us-gaap_RangeMember_3AC6FD2709E4C38F55BC1776C41E2CA9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_3AC6FD2709E4C38F55BC1776C41E2CA9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_F34271FBB20071A925131776C41E1AC4" xlink:to="loc_us-gaap_RangeMember_3AC6FD2709E4C38F55BC1776C41E2CA9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_9FD779662203BAFE79DC1776C423D001" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_3AC6FD2709E4C38F55BC1776C41E2CA9" xlink:to="loc_us-gaap_MaximumMember_9FD779662203BAFE79DC1776C423D001" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9C735EBEC9605C87A7781776C4248814" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_497DCE9132538936FBB91776C41D7A83" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9C735EBEC9605C87A7781776C4248814" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_8A452718383F0197688C1776C424DCD6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9C735EBEC9605C87A7781776C4248814" xlink:to="loc_us-gaap_RelatedPartyDomain_8A452718383F0197688C1776C424DCD6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_8A452718383F0197688C1776C424DCD6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_9C735EBEC9605C87A7781776C4248814" xlink:to="loc_us-gaap_RelatedPartyDomain_8A452718383F0197688C1776C424DCD6" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NrgMember" xlink:label="loc_nrg_NrgMember_5750C3F63B1D1E39AAFF1776C424D163" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_8A452718383F0197688C1776C424DCD6" xlink:to="loc_nrg_NrgMember_5750C3F63B1D1E39AAFF1776C424D163" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_707C14AD7D45527140A21776C424C153" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_497DCE9132538936FBB91776C41D7A83" xlink:to="loc_dei_LegalEntityAxis_707C14AD7D45527140A21776C424C153" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_90A62C1533CD8496757D1776C424D3C1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_707C14AD7D45527140A21776C424C153" xlink:to="loc_dei_EntityDomain_90A62C1533CD8496757D1776C424D3C1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_90A62C1533CD8496757D1776C424D3C1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_707C14AD7D45527140A21776C424C153" xlink:to="loc_dei_EntityDomain_90A62C1533CD8496757D1776C424D3C1" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGDGPVHoldco2Member" xlink:label="loc_nrg_NRGDGPVHoldco2Member_5251C963696366CA67E01776C424900A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_90A62C1533CD8496757D1776C424D3C1" xlink:to="loc_nrg_NRGDGPVHoldco2Member_5251C963696366CA67E01776C424900A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_934E611B3337540BAC791776C4244838" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_497DCE9132538936FBB91776C41D7A83" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_934E611B3337540BAC791776C4244838" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_934E611B3337540BAC791776C4244838" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_934E611B3337540BAC791776C4244838" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGDGPVHoldco3Member" xlink:label="loc_nrg_NRGDGPVHoldco3Member_3C46A15118F8286169CB1776C4252FF1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914" xlink:to="loc_nrg_NRGDGPVHoldco3Member_3C46A15118F8286169CB1776C4252FF1" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_UtahPortfolioMember" xlink:label="loc_nrg_UtahPortfolioMember_24A44F099B9824CD07F11776C4255752" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914" xlink:to="loc_nrg_UtahPortfolioMember_24A44F099B9824CD07F11776C4255752" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGDGPVHoldcoMember" xlink:label="loc_nrg_NRGDGPVHoldcoMember_50C7A3BB484E5C68EBFD1776C4253ACA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914" xlink:to="loc_nrg_NRGDGPVHoldcoMember_50C7A3BB484E5C68EBFD1776C4253ACA" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_FourBrothersSolarMember" xlink:label="loc_nrg_FourBrothersSolarMember_E0014433944BE626963E1776C425B065" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914" xlink:to="loc_nrg_FourBrothersSolarMember_E0014433944BE626963E1776C425B065" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_GraniteMountainHoldingsMember" xlink:label="loc_nrg_GraniteMountainHoldingsMember_FB85138E61EACDA8F0DD1776C425E784" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914" xlink:to="loc_nrg_GraniteMountainHoldingsMember_FB85138E61EACDA8F0DD1776C425E784" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_IronSpringsHoldingsMember" xlink:label="loc_nrg_IronSpringsHoldingsMember_0ED7A14A714FA188C4F31776C4251B70" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914" xlink:to="loc_nrg_IronSpringsHoldingsMember_0ED7A14A714FA188C4F31776C4251B70" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGDGPVHoldco1Member" xlink:label="loc_nrg_NRGDGPVHoldco1Member_F4A494D29C8F33D257861776C42576C6" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914" xlink:to="loc_nrg_NRGDGPVHoldco1Member_F4A494D29C8F33D257861776C42576C6" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGDGPVHoldco2Member" xlink:label="loc_nrg_NRGDGPVHoldco2Member_F33B3889B450B53A412D1776C4251446" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914" xlink:to="loc_nrg_NRGDGPVHoldco2Member_F33B3889B450B53A412D1776C4251446" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_NRGRPVHoldcoMember" xlink:label="loc_nrg_NRGRPVHoldcoMember_A81DF2671311D62A69EE1776C42501D2" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914" xlink:to="loc_nrg_NRGRPVHoldcoMember_A81DF2671311D62A69EE1776C42501D2" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_GenConnEnergyLlcMember" xlink:label="loc_nrg_GenConnEnergyLlcMember_6950A0A548605BE476A11776C4258BEB" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914" xlink:to="loc_nrg_GenConnEnergyLlcMember_6950A0A548605BE476A11776C4258BEB" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_GceHoldingLlcMember" xlink:label="loc_nrg_GceHoldingLlcMember_421AC7D14FBA452BFA571776C4264C3E" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E3961B4ED911807846E51776C4254914" xlink:to="loc_nrg_GceHoldingLlcMember_421AC7D14FBA452BFA571776C4264C3E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates" xlink:label="loc_us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates_EEFE37749E85686B351E1776C426864A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:to="loc_us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates_EEFE37749E85686B351E1776C426864A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_CE99A21CE33E785AFDBA1776C426C898" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:to="loc_us-gaap_Revenues_CE99A21CE33E785AFDBA1776C426C898" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:label="loc_us-gaap_EquityMethodInvestments_C1AE7CE7FAAF8E6983B61776C426C3AC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:to="loc_us-gaap_EquityMethodInvestments_C1AE7CE7FAAF8E6983B61776C426C3AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_272EE495D0BE0BA9E5771776C42B41D0" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:to="loc_us-gaap_OperatingIncomeLoss_272EE495D0BE0BA9E5771776C42B41D0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_1D8E2C73778C89BF0F2E1776C42B0B64" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:to="loc_us-gaap_ProfitLoss_1D8E2C73778C89BF0F2E1776C42B0B64" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_095AC78A75344B329BE71776C42B90EA" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:to="loc_us-gaap_AssetsCurrent_095AC78A75344B329BE71776C42B90EA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsNoncurrent" xlink:label="loc_us-gaap_AssetsNoncurrent_B552A74BFEE0FF4B73321776C42C17EB" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:to="loc_us-gaap_AssetsNoncurrent_B552A74BFEE0FF4B73321776C42C17EB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_20CADBEFA0F6E49253EE1776C42C12F0" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:to="loc_us-gaap_LiabilitiesCurrent_20CADBEFA0F6E49253EE1776C42C12F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesNoncurrent" xlink:label="loc_us-gaap_LiabilitiesNoncurrent_1137278DCF500E6D01B51776C42C3BA5" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:to="loc_us-gaap_LiabilitiesNoncurrent_1137278DCF500E6D01B51776C42C3BA5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount" xlink:label="loc_us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount_8A86F2C6231372950BE01776C42C9CA9" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:to="loc_us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount_8A86F2C6231372950BE01776C42C9CA9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DueToAffiliateCurrentAndNoncurrent" xlink:label="loc_us-gaap_DueToAffiliateCurrentAndNoncurrent_E164E3B97FF993CBBFC81776C42C389D" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:to="loc_us-gaap_DueToAffiliateCurrentAndNoncurrent_E164E3B97FF993CBBFC81776C42C389D" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PowerGenerationCapacityMegawatts" xlink:label="loc_nrg_PowerGenerationCapacityMegawatts_E20DF549AC864C656A3C1776C42C3910" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:to="loc_nrg_PowerGenerationCapacityMegawatts_E20DF549AC864C656A3C1776C42C3910" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_RemainingLeaseTerm" xlink:label="loc_nrg_RemainingLeaseTerm_5F630E4E3FC27ADBE0401776C42C3AF8" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5233578C3F1672D19BF01776C42668FA" xlink:to="loc_nrg_RemainingLeaseTerm_5F630E4E3FC27ADBE0401776C42C3AF8" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nrgenergy.com/role/VariableInterestEntitiesVariableInterestEntitiesUtahSolarPortfolioDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableInterestEntityLineItems" xlink:label="loc_us-gaap_VariableInterestEntityLineItems_545CEC474827BB8725F0FD65C5007538" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_7FD3E3C465EBB6A00930FD65C50091B9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_545CEC474827BB8725F0FD65C5007538" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_7FD3E3C465EBB6A00930FD65C50091B9" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherOwnershipInterestsByNameAxis" xlink:label="loc_us-gaap_OtherOwnershipInterestsByNameAxis_ACAA69C61987639BBCB2FD65C500EF9C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_7FD3E3C465EBB6A00930FD65C50091B9" xlink:to="loc_us-gaap_OtherOwnershipInterestsByNameAxis_ACAA69C61987639BBCB2FD65C500EF9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherOwnershipInterestsNameDomain" xlink:label="loc_us-gaap_OtherOwnershipInterestsNameDomain_D8FE1A60CA3E5F146FCFFD65C500BB65_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherOwnershipInterestsByNameAxis_ACAA69C61987639BBCB2FD65C500EF9C" xlink:to="loc_us-gaap_OtherOwnershipInterestsNameDomain_D8FE1A60CA3E5F146FCFFD65C500BB65_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherOwnershipInterestsNameDomain" xlink:label="loc_us-gaap_OtherOwnershipInterestsNameDomain_D8FE1A60CA3E5F146FCFFD65C500BB65" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherOwnershipInterestsByNameAxis_ACAA69C61987639BBCB2FD65C500EF9C" xlink:to="loc_us-gaap_OtherOwnershipInterestsNameDomain_D8FE1A60CA3E5F146FCFFD65C500BB65" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_FinancialInstitutionsMember" xlink:label="loc_nrg_FinancialInstitutionsMember_05A910FB68AE8F90BBDDFD65C500D4C1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherOwnershipInterestsNameDomain_D8FE1A60CA3E5F146FCFFD65C500BB65" xlink:to="loc_nrg_FinancialInstitutionsMember_05A910FB68AE8F90BBDDFD65C500D4C1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityInterestIssuedOrIssuableByTypeAxis" xlink:label="loc_us-gaap_EquityInterestIssuedOrIssuableByTypeAxis_8B84439D3ED6B040DEA6FD65C5002AE5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_7FD3E3C465EBB6A00930FD65C50091B9" xlink:to="loc_us-gaap_EquityInterestIssuedOrIssuableByTypeAxis_8B84439D3ED6B040DEA6FD65C5002AE5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityInterestIssuedOrIssuableTypeDomain" xlink:label="loc_us-gaap_EquityInterestIssuedOrIssuableTypeDomain_E8F2CBC295EF686433FCFD65C500EAD2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_EquityInterestIssuedOrIssuableByTypeAxis_8B84439D3ED6B040DEA6FD65C5002AE5" xlink:to="loc_us-gaap_EquityInterestIssuedOrIssuableTypeDomain_E8F2CBC295EF686433FCFD65C500EAD2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityInterestIssuedOrIssuableTypeDomain" xlink:label="loc_us-gaap_EquityInterestIssuedOrIssuableTypeDomain_E8F2CBC295EF686433FCFD65C500EAD2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_EquityInterestIssuedOrIssuableByTypeAxis_8B84439D3ED6B040DEA6FD65C5002AE5" xlink:to="loc_us-gaap_EquityInterestIssuedOrIssuableTypeDomain_E8F2CBC295EF686433FCFD65C500EAD2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CapitalUnitClassAMember" xlink:label="loc_us-gaap_CapitalUnitClassAMember_1F8D4EDC395F9EFFE218FD65C500D086" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityInterestIssuedOrIssuableTypeDomain_E8F2CBC295EF686433FCFD65C500EAD2" xlink:to="loc_us-gaap_CapitalUnitClassAMember_1F8D4EDC395F9EFFE218FD65C500D086" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CapitalUnitClassBMember" xlink:label="loc_us-gaap_CapitalUnitClassBMember_E8B4528A9AAB259650CDFD65C5007253" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityInterestIssuedOrIssuableTypeDomain_E8F2CBC295EF686433FCFD65C500EAD2" xlink:to="loc_us-gaap_CapitalUnitClassBMember_E8B4528A9AAB259650CDFD65C5007253" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_C31E6CF3CE3FD6FD4939FD65C5005518" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_7FD3E3C465EBB6A00930FD65C50091B9" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_C31E6CF3CE3FD6FD4939FD65C5005518" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_4112C6EFD63F5C55170FFD65C500817A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_C31E6CF3CE3FD6FD4939FD65C5005518" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_4112C6EFD63F5C55170FFD65C500817A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_4112C6EFD63F5C55170FFD65C500817A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_C31E6CF3CE3FD6FD4939FD65C5005518" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_4112C6EFD63F5C55170FFD65C500817A" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_UtahPortfolioMember" xlink:label="loc_nrg_UtahPortfolioMember_F101AF79FB42971703DFFD65C500A01E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_4112C6EFD63F5C55170FFD65C500817A" xlink:to="loc_nrg_UtahPortfolioMember_F101AF79FB42971703DFFD65C500A01E" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PercentageOfOwnership" xlink:label="loc_nrg_PercentageOfOwnership_9EBF05F6DE405E318C60FD65C5006340" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_545CEC474827BB8725F0FD65C5007538" xlink:to="loc_nrg_PercentageOfOwnership_9EBF05F6DE405E318C60FD65C5006340" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_TaxableIncomeAllocationPreFlip" xlink:label="loc_nrg_TaxableIncomeAllocationPreFlip_7C377C689CA9C58E0B31FD65C5001D0C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_545CEC474827BB8725F0FD65C5007538" xlink:to="loc_nrg_TaxableIncomeAllocationPreFlip_7C377C689CA9C58E0B31FD65C5001D0C" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_TaxableIncomeAllocationPostFlip" xlink:label="loc_nrg_TaxableIncomeAllocationPostFlip_5E4C4E7E453F181F6E78FD65C50025CA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_545CEC474827BB8725F0FD65C5007538" xlink:to="loc_nrg_TaxableIncomeAllocationPostFlip_5E4C4E7E453F181F6E78FD65C50025CA" xlink:type="arc" />
    <link:loc xlink:href="nrg-20180331.xsd#nrg_PercentageofCashAvailableforDistributions" xlink:label="loc_nrg_PercentageofCashAvailableforDistributions_CF043B61CFA9A2B50FCCFD65C500ADF7" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_545CEC474827BB8725F0FD65C5007538" xlink:to="loc_nrg_PercentageofCashAvailableforDistributions_CF043B61CFA9A2B50FCCFD65C500ADF7" xlink:type="arc" />
  </link:definitionLink>
</link:linkbase>
