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  <xs:element id="pagp_InventoryWeightedAveragePricePerUnitLinefill" abstract="false" name="InventoryWeightedAveragePricePerUnitLinefill" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="srt-types:perUnitItemType"/>
  <xs:element id="pagp_InventoryWeightedAveragePricePerUnitNoncurrent" abstract="false" name="InventoryWeightedAveragePricePerUnitNoncurrent" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="srt-types:perUnitItemType"/>
  <xs:element id="pagp_ScheduleOfDebtInstrumentsTable" abstract="true" name="ScheduleOfDebtInstrumentsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="pagp_SeniorNotesDueinDecember2026At4.50PercentMember" abstract="true" name="SeniorNotesDueinDecember2026At4.50PercentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_OtherDebtMember" abstract="true" name="OtherDebtMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_OtherLongTermDebtMember" abstract="true" name="OtherLongTermDebtMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_TermLoanMember" abstract="true" name="TermLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_ScheduleOfDebtInstrumentsLineItems" abstract="true" name="ScheduleOfDebtInstrumentsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="pagp_LineOfCreditAndCommercialPaperMember" abstract="true" name="LineOfCreditAndCommercialPaperMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_SeniorUnsecuredRevolvingCreditFacilityMember" abstract="true" name="SeniorUnsecuredRevolvingCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_SeniorSecuredHedgedInventoryFacilityMember" abstract="true" name="SeniorSecuredHedgedInventoryFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_TermLoanAgreementMember" abstract="true" name="TermLoanAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_LineOfCreditFacilityAccordionFeatureIncreaseLimit" abstract="false" name="LineOfCreditFacilityAccordionFeatureIncreaseLimit" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_NumberOfOneYearExtensionsProvidedForUnderAgreement" abstract="false" name="NumberOfOneYearExtensionsProvidedForUnderAgreement" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="pagp_LineOfCreditFacilityPeriodForWhichTermOfCreditFacilityMayBeExtended" abstract="false" name="LineOfCreditFacilityPeriodForWhichTermOfCreditFacilityMayBeExtended" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="pagp_SharesClassBMember" abstract="true" name="SharesClassBMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_SharesClassCMember" abstract="true" name="SharesClassCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_CommonEquityRepurchaseProgramMember" abstract="true" name="CommonEquityRepurchaseProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_LimitedPartnersCapitalAccountSharesIssuedExchangedinExchangeRightExercises" abstract="false" name="LimitedPartnersCapitalAccountSharesIssuedExchangedinExchangeRightExercises" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="pagp_PartnersCapitalAccountSharesCancellationOfShares" abstract="false" name="PartnersCapitalAccountSharesCancellationOfShares" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="pagp_PartnersCapitalUnitsOther" abstract="false" name="PartnersCapitalUnitsOther" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="pagp_PartnersCapitalAndDistributionsLineItems" abstract="true" name="PartnersCapitalAndDistributionsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="pagp_PlainsOryxPermianBasinLLCMember" abstract="true" name="PlainsOryxPermianBasinLLCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_CactusIIPipelineLLCMember" abstract="true" name="CactusIIPipelineLLCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_RedRiverPipelineCompanyLLCMember" abstract="true" name="RedRiverPipelineCompanyLLCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_CommonUnitsAndSeriesAPreferredUnitsMember" abstract="true" name="CommonUnitsAndSeriesAPreferredUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_NumberOfDaysRequiredForDistributionToUnitholdersAfterEndOfQuarter" abstract="false" name="NumberOfDaysRequiredForDistributionToUnitholdersAfterEndOfQuarter" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="pagp_PublicUnitHoldersMember" abstract="true" name="PublicUnitHoldersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_ConsolidatedJointVentureEntitiesMember" abstract="true" name="ConsolidatedJointVentureEntitiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_ContractsRelatedToCrudeOilPurchasesMember" abstract="true" name="ContractsRelatedToCrudeOilPurchasesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_TimeSpreadOnHedgeAnticipatedCrudeOilLeaseGatheringPurchaseContractsMember" abstract="true" name="TimeSpreadOnHedgeAnticipatedCrudeOilLeaseGatheringPurchaseContractsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_CrudeOilBasisSpreadPositionMember" abstract="true" name="CrudeOilBasisSpreadPositionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_AnticipatedNetSalesOfInventoryMember" abstract="true" name="AnticipatedNetSalesOfInventoryMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_DeferredGainLossOnAccumulatedOtherComprehensiveIncomeLossNetOfTax" abstract="false" name="DeferredGainLossOnAccumulatedOtherComprehensiveIncomeLossNetOfTax" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_InitialMargin" abstract="false" name="InitialMargin" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_VariationMarginPosted" abstract="false" name="VariationMarginPosted" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_OffsettingAssetsLiabilitiesTable" abstract="true" name="OffsettingAssetsLiabilitiesTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="pagp_OffsettingAssetsLiabilitiesLineItems" abstract="true" name="OffsettingAssetsLiabilitiesLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="pagp_Line901IncidentMember" abstract="true" name="Line901IncidentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_Line9012015InsuranceProgramMember" abstract="true" name="Line9012015InsuranceProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_Line48IncidentMember" abstract="true" name="Line48IncidentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_Line63IncidentMember" abstract="true" name="Line63IncidentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pagp_InsuranceCoverageLimit" abstract="false" name="InsuranceCoverageLimit" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_EstimatedSizeOfRelease" abstract="false" name="EstimatedSizeOfRelease" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:volumeItemType"/>
  <xs:element id="pagp_LossContingencySelfInsuredRetention" abstract="false" name="LossContingencySelfInsuredRetention" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_LossContingencyCleanUpAndRemediationActivities" abstract="false" name="LossContingencyCleanUpAndRemediationActivities" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_LossContingencyCleanUpAndRemediateAggregateCost" abstract="false" name="LossContingencyCleanUpAndRemediateAggregateCost" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_GeneralAndAdministrativeExpenseExcludingUnallocatedAmount" abstract="false" name="GeneralAndAdministrativeExpenseExcludingUnallocatedAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_SignificantSegmentExpenses" abstract="false" name="SignificantSegmentExpenses" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_DepreciationAndAmortizationOfUnconsolidatedEntities" abstract="false" name="DepreciationAndAmortizationOfUnconsolidatedEntities" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_GainsLossesFromDerivativeActivitiesAndInventoryValuationAdjustments" abstract="false" name="GainsLossesFromDerivativeActivitiesAndInventoryValuationAdjustments" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_LongTermInventoryCostingAdjustments" abstract="false" name="LongTermInventoryCostingAdjustments" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_DeficienciesUnderMinimumVolumeCommitmentsNet" abstract="false" name="DeficienciesUnderMinimumVolumeCommitmentsNet" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_EquityIndexedCompensationExpenseAwardsThatWillBeSettledInUnits" abstract="false" name="EquityIndexedCompensationExpenseAwardsThatWillBeSettledInUnits" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_NetGainLossOnForeignCurrencyRevaluation" abstract="false" name="NetGainLossOnForeignCurrencyRevaluation" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_TransactionRelatedExpenses" abstract="false" name="TransactionRelatedExpenses" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_SegmentAmountsAttributableToNoncontrollingInterests" abstract="false" name="SegmentAmountsAttributableToNoncontrollingInterests" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_SegmentAdjustedEBITDA" abstract="false" name="SegmentAdjustedEBITDA" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_InvestmentAndAcquisitionCapitalExpenditures" abstract="false" name="InvestmentAndAcquisitionCapitalExpenditures" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pagp_MaintenanceCapitalExpenditures" abstract="false" name="MaintenanceCapitalExpenditures" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
