2ResearchstudyEnergyStorageInspection2023AuthorsHTWBerlin(topic1to4)JohannesWeniger,NicoOrth,LucasMeissner,CheyenneSchlüter,JonasMeyneSolarStorageSystemsResearchGroupHTWBerlin–UniversityofAppliedSciencesCo-authorsKIT(topic4)RobertSchreier,BernhardSchwarz,NinaMunzkeInstituteofElectricalEngineering(ETI)KarlsruheInstituteofTechnology(KIT)ReleaseVersion1.0(February2023)Websitesolar.htw-berlin.de/inspektion3Inverterefficiency:Averageefficiencyduringdischarging,Standbypowerconsumptioninthedischargedstate.4TheefficiencybenchmarkingisbasedontheSystemPerformanceIndexSPI(5kW)andSPI(10kW).5Thebatterylossesofthesodium-nickelchloridebatteryareseventimeshigherthanthoseofthelithium-ionbattery.6Maximumdischargepowerofdifferentbatteytechnologiesduringthedischargeprocess.71AnalysisoftheGermanmarketforresidentialPV-batterysystems2ComparisonofthesystempropertiesbasedonthetestreportsaccordingtotheEfficiencyGuideline3Simulation-basedassessmentofthePV-batterysystemswiththeSystemPerformanceIndex(SPI)4Analysisofsodium-ionandsodium-nickelchloridebatterysystemsMaintopicsoftheEnergyStorageInspection202381AnalysisoftheGermanmarketforresidentialPV-batterysystems2ComparisonofthesystempropertiesbasedonthetestreportsaccordingtotheEfficiencyGuideline3Simulation-basedassessmentofthePV-batterysystemswiththeSystemPerformanceIndex(SPI)4Analysisofsodium-ionandsodium-nickelchloridebatterysystemsMaintopicsoftheEnergyStorageInspection20239DevelopmentoftheGermanmarketforPV-batterysystemsData:Marktstammdatenregister,PVsystemsbetween2kWand20kW,batterysystemssmallerthan20kWhand20kW10DevelopmentofthemeanvaluesofthePV-batterysystemsData:Marktstammdatenregister,PVsystemsbetween2kWand20kW,batterysystemssmallerthan20kWhand20kW11RatedpowerofthenewlyinstalledPVsystemsupto20kWData:Marktstammdatenregister,PVsystemsbetween2kWand20kW12Usablebatterycapacityofthebatterysystemsupto20kWhData:Marktstammdatenregister,batterysystemssmallerthan20kWhand20kW13SystemtopologiesofthePV-storagesystemsinGermanyData:Marktstammdatenregister,batterysystemssmallerthan20kWhand20kW14MarketshareofthecathodematerialsinhomestoragesystemsEstimationofHTWBerlinbasedondatasheetspecificationsandmanufacturerinformationsaswellasmarketdataofEUPDResearch.15FactsandfiguresaboutthePV-storagemarketinGermanyData:Marktstammdatenregister,status:01.02.2023161AnalysisoftheGermanmarketforresidentialPV-batterysystems2ComparisonofthesystempropertiesbasedonthetestreportsaccordingtotheEfficiencyGuideline3Simulation-basedassessmentofthePV-batterysystemswiththeSystemPerformanceIndex(SPI)4Analysisofsodium-ionandsodium-nickelchloridebatterysystemsMaintopicsoftheEnergyStorageInspection202317ParticipantsoftheEnergyStorageInspection2023•ForthesixthtimeinarowallmanufacturersofsolarenergystoragesystemsforresidentialbuildingswereinvitedtotakepartintheEnergyStorageInspection2023.•11manufacturesparticipatedinthecomparisonofthestoragesystemswithmeasurementdataof18systems.•Twomanufacturersdecidedtoparticipateanonymously.18AnalysisofsystempropertiesaccordingtotheEfficiencyGuideline•Laboratorytestswereconductedbyindependenttestinginstitutesinaccordancewiththe"EfficiencyGuidelineforPVStorageSystems”(version2.0).•Toeachanalyzedsystemasystemabbreviation(e.g.A1)wasassigned.•ThebatteriesoftheAC-coupledsystemsA1toB2areequippedwithbatteryinverters.TheDC-coupledsystemsB3toI2havesocalledhybridinverters.•DetailsaboutthemethodologycanbefoundintheEnergyStorageInspection2018and2021.19AnalyzedsystemsoftheEnergyStorageInspection202320AnalyzedsystemsoftheEnergyStorageInspection202321AnalyzedsystemsoftheEnergyStorageInspection202322AnalyzedsystemsoftheEnergyStorageInspection202323AnalyzedsystemsoftheEnergyStorageInspection202324AnalyzedsystemsoftheEnergyStorageInspection202325UsablebatterycapacityoftheanalyzedsystemsSystemF1andF2:Duetoatemperature-inducedderating,thetestcouldonlyberunat50%und25%ofthenominalpower.26ComparisonofdatasheetvaluesandlaboratorymeasurementsFor11ofthe18analyzedsystemslowerusablebatterycapacitiesweremeasuredinthelaboratorytestcomparedtothedatasheet.Thespecifieddepthofdischargeforprotectionagainstdeepdischargeisoftenthereasonwhythemeasuredvaluesarelower.27Nominaldischargepoweroftheanalyzedsystems28NominaloutputpoweroftheDC-coupledsystemsSystemB3B4B5C1C2D1D2E1E2PowerinkW4.55.59.96.110.25.010.010.110.3SystemF1F2G1H1I1I2PowerinkW5.910.04.510.14.57.8•Inpractice,theratioofinverteroutputpowertoPVgeneratorpowerisoftenbetween80%and90%.•InDC-coupledsystems,theso-calledPVratedoutputpowerlimitsthepoweroutputofthePV-storagesystem.•ThemanufacturerofthesystemI2specifiesaoutputof10kWonthedatasheet.However,inthelaboratorytestonlyaoutputpowerof7,8kWcouldbemeasured.29Energyconversionpathwaysofthedifferentsystemtopologies30AveragepathefficiencyforcomparisonoftheconversionefficiencyTheaveragepathwayefficiencycorrespondstothearithmeticmeanoftheefficienciesat10equidistantlydistributedsamplingpoints.31AverageconversionefficiencyofACbatterydischargingAveragepathwayefficienciesofACdischargingaccordingtothe“EfficiencyGuidelineforPVStorageSystems”2.0.32AverageefficiencyoftheenergyconversionpathwaysAveragepathwayefficienciesofACdischargingaccordingtothe“EfficiencyGuidelineforPVStorageSystems”2.0.33PVfeed-inpathwayefficiencyW1andW2:PVinverterusedforassessingtheAC-coupledsystemswiththeSPI(5kW)andSPI(10kW).34PVbatterychargingpathwayefficiency35ACbatterychargingpathwayefficiency36ACbatterydischargingpathwayefficiency37AveragebatteryefficiencySystemF1andF2:Duetoatemperature-inducedderating,thetestcouldonlyberunat50%und25%ofthenominalpower.38Dynamiccontroldeviations39StationarycontroldeviationsSystemH1:Gridsupplypowerduringcharging63W,gridfeed-inpowerduringdischarging137W.40DwelltimeinthefullychargedstateofthebatterysystemSimulationresultsforasingle-familyhousewithanelectricityconsumptionof5010kWh/a.41Standbypowerconsumptionwithfullychargedbattery42DwelltimeinthefullydischargedstateofthebatterysystemSimulationresultsforasingle-familyhousewithanelectricityconsumptionof5010kWh/a.43Standbypowerconsumptionwithdischargedbattery44StandbypowerconsumptionofthebatterymanagementsystemData:Manufacturer'sdatanotdeterminedbyindependenttestinginstitutes.451AnalysisoftheGermanmarketforresidentialPV-batterysystems2ComparisonofthesystempropertiesbasedonthetestreportsaccordingtotheEfficiencyGuideline3Simulation-basedassessmentofthePV-batterysystemswiththeSystemPerformanceIndex(SPI)4Analysisofsodium-ionandsodium-nickelchloridebatterysystemsMaintopicsoftheEnergyStorageInspection202346Methodologyofthesimulation-basedsystemevaluation•SimulationoftheoperationalbehaviorofthePV-batterysystemsoveraperiodofoneyear.•TheSystemPerformanceIndex(SPI)ratesthesystemsbasedontheenergyflowsatthegridconnectionpoint.TheSPItakesintoaccountthedifferenteconomicvalueoftheenergyfedintothegridanddrawnfromthegrid.•Changesintheregulatoryframework,newretailelectricitypricesandnewfeed-intariffratesrequireachangeintheframeworkconditionsfordeterminingtheSPI.FrameworkconditionsforthedeterminationoftheSystemPerformanceIndex(SPI)until2022from2023Considerationofthe70%feed-inlimityesnoFeed-intariff12ct/kWh8ct/kWhRetailelectricityprice30ct/kWh40ct/kWh47Methodologyofthesimulation-basedsystemevaluation•Parameterizationofthesimulationmodel„PerMod“(version2.2)withthelaboratorymeasurementsresultsdeterminedaccordingtotheEfficiencyGuideline.•Considerationofthesizing,conversion,controlandstandbylossesbasedonthelaboratorymeasurements.48SystemPerformanceIndexSPI(5kW)andSPI(10kW)Pleasenote:SPI(5kW)andSPI(10kW)arenotcomparableduetothedifferentconditionsofthetworeferencecases.+++1referencecasefortheSystemPerformanceIndexSPI(5kW)stAppliances(5010kWh/a)PVsystem(5kW)Appliances(5010kWh/a)PVsystem(10kW)Heatpump(2664kWh/a)Electricvehicle(1690kWh/a)2referencecasefortheSystemPerformanceIndexSPI(10kW)nd49Gridfeed-inandgridsupplylossesoftherealPV-batterysystemsReductioningridfeed-inandincreaseingridsupplyduetotheefficiencylossesofthePV-batterysystemF2andH1.Frameworkconditionsofthesimulation:PVpower10kWandelectricityconsumptionofthehousehold9363kWh/a(2ndreferencecase).50ExampleforthedeterminationoftheSPIGridfeed-inrevenuesandretailelectricitycosts,aswellascostsavingsoftheideal(lossless)andrealPV-batterysystemH1(gridfeed-intariff0.08€/kWh,retailelectricityprice0.4€/kWh).Frameworkconditionsofthe2ndreferencecase.51Assignmentofthesystemstothereferencecases•Dependingonthesizeofthepowerelectronicsandbatterystorage,theefficiencyratingwiththeSPI(5kW)orSPI(10kW)isappropriate.•Onlysystemswithusablebatterycapacitiessmallerthan8.0kWhwereratedwiththeSPI(5kW).•ForaratingwiththeSPI(10kW)anusablebatterycapacitysmallerthan16.0kWhwasrequired.•Theclassificationwasbasedontheusablestoragecapacitydeterminedinthelaboratorytest.•9systemswereratedwiththeSPI(5kW)and10systemswereratedwiththeSPI(10kW).BothmetricsweredeterminedfortheAC-coupledsystemA1.SystemA1B1B2B3B4B5C1C2D1D2E1E2F1F2G1H1I1I2SPI(5kW)SPI(10kW)52InfluenceofthechangedframeworkconditionsontheSPI•ThenewframeworkconditionsleadtoanincreaseintheSPIcomparedtothevaluesdeterminedinpreviousyears.•Byeliminatingthe70%feed-inlimit,theassociatedenergymanagementlossesarenolongerconsidered.•OnaveragethechangeincreasestheSPI(5kW)by+0,5percentagepointsandtheSPI(10kW)raisesby+0,8percentagepoints.•Duetotheincreasingdifferencebetweenfeed-intariffandretailelectricityprice,thelossesthatleadtoahighergridsupplybecomemoresignificantcomparedtothelossesthatonlyreducethegridfeed-in.•Consideringallchangedparameter,theSPI(5kW)increasescomparedtothepreviouscalculationsbyanaverageof+0,6percentagepoints.TheSPI(10kW)increasesbyanaverageof+0,9percentagepoints.53ChangeoftheSPIincomparisontothepreviousdeterminationNewframeworkconditions:Nofeed-inlimitationto70%,gridfeed-intariff0.08€/kWh,retailelectricityprice0.4€/kWh.54LossanalysisofthesystemsassessedwiththeSPI(5kW)55LossanalysisofthesystemsassessedwiththeSPI(10kW)56DefinitionoftheefficiencyclassesforPV-batterysystems•DuetothechangedSPIvalues,theefficiencyclasseswerealsoadjusted.•Thethresholdvaluesforreachingthedifferentclasseswereincreasedby0.5percentagepointsforSPI(5kW)andby1percentagepointforSPI(10kW).ClassSPI(5kW)SPI(10kW)A≥92.5%≥94.5%B≥90.5%≥93.5%C≥88.5%≥92.5%D≥86.5%≥91.5%E≥84.5%≥90.5%F≥82.5%≥89.5%G<82.5%<89.5%57SPI(5kW)andefficiencyclassesoftheanalyzedsystemsTheAC-coupledsystemsA1andB1areassessedincombinationwiththePVinverterSMASunnyBoy5.0.58SPI(10kW)andefficiencyclassesoftheanalyzedsystemsTheAC-coupledsystemsA1andB2areassessedincombinationwiththePVinverterSMASunnyTripower10.0.59Whyisahighsystemefficiencyimportant?•EfficiencylossesreducethecostsavingspotentialofaPV-batterysystem.TheeconomiclossesforthesystemsevaluatedwiththeSPI(10kW)arebetween94€/aand261€/a.•ThosewhochooseanhighlyefficientPV-batterysystemcansaveuptoanadditional1700€withinthefirsttenyearsofoperationcomparedtoalessefficientsystem.Frameworkconditionsofthe2ndreferencecase.60Summaryofthesystemevaluationresults•TheEnergyStorageInspection2023analyzedandcomparedtheenergyefficiencyof18batterysystems.•Withanaverageinverterefficiencyindischargemodeof97.8%andasettlingtimeoflessthan0.2s,newrecordswereset.•Inthereferencecaseupto5kWthehybridinvertersF1andC1scoredbestwithanSPI(5kW)of92.6%.•SystemF2wonthe10kWreferencecasewithanSPI(10kW)of96.4%.•14ofthe18systemsexaminedachievedverygoodsystemefficienciesandreachedtheefficiencyclassesAandB.•Whiletheconversionlossescontinuetobemainlyresponsiblefortheoveralllosses,thelosscategorythatleadstothesecondhighestlossesvariesdependingonthesystem.solar.htw-berlin.de611AnalysisoftheGermanmarketforresidentialPV-batterysystems2ComparisonofthesystempropertiesbasedonthetestreportsaccordingtotheEfficiencyGuideline3Simulation-basedassessmentofthePV-batterysystemswiththeSystemPerformanceIndex(SPI)4Analysisofsodium-ionandsodium-nickelchloridebatterysystemsMaintopicsoftheEnergyStorageInspection202362PermissibleoperatingtemperaturerangeData:Datasheetinformationofselectedproductsfromdifferentmanufacturers.63GravimetricenergydensityData:Datasheetinformationofselectedproductsfromdifferentmanufacturers.64Evaluationofalternativebatterysystems•Inrecentyears,thehomestoragemarkethasseentheintroductionofnumerousnewproducts,includingsodium-ion,sodium-nickelchloride,nickelmetalhydrideandredoxflowstoragesystems.•Foracomprehensiveanalysisofthealternativebatterysystems,asmanydifferentproductsaspossibleshouldbeacquired.However,duetocompanyinsolvenciesordeliverydifficultiesonlyonesodium-ionandonesodium-nickelchloridesystemwereavailable.•Commonly,theyarealsoreferredtoassaltwaterbatteryandhigh-temperaturebattery.•ThetwosystemsweremeasuredinthetestlaboratoriesoftheKarlsruheInstituteofTechnology(KIT).•Inadditiontodetailedefficiencymeasurements,therealoperatingbehaviorofthealternativesystemswasrecordedoveranapplicationtestlastingseveraldays.65Chargeanddischargeefficiencyofsodium-nickelchloridebattery66Dischargepowerofsodium-ionbatteryResponseofsodium-ionbatterytoaconstantelectricalloadof2.2kWwiththePVsimulatordeactivated.67ChargeanddischargepowerofthealternativebatteriesChargeanddischargepowerduringthebatterytestwithnominalpoweraccordingtotheEfficiencyGuideline.Displayofthemeasuredvaluesofthe3rdcycle.68ChargedanddischargedenergyofthealternativebatteriesDCenergyoutputandconsumptionduringthecycletestsatdifferentpowerlevels.Averagevaluebasedonthemeasuredvaluesofthe2ndand3rdcycleperpowerlevel.Datasheetvaluebasedonmanufacturer'sspecifications.69MeanbatteryefficiencyofdifferentbatterytechnologiesLithium-ionbattery:Measuredvaluesofalithium-ionbatterysystemofthefirstproductgenerationfrom2018.70Standbypowerconsumptionofthesodium-nickelchloridebatteryPowerconsumptionofthehigh-temperaturebatteryinthedischargedstate.Tomaintaintheminimumbatteryoperatingtemperatureof265C,thebatterysystemdrawsanaverageof130Wfromthegrid.°71OperatingbehaviorofthebatterysystemsoverseveraldaysResidualpower(PVpowerminuselectricalload)andmeasuredACpowerofthe3storagesystemsinvestigatedduringthesix-dayapplicationtest.72OperatingbehaviorofthebatterysystemsduringanautumndayDay4oftheapplicationtest:Residualpower(PVpowerminuselectricalload)andmeasuredACpowerofthe3storagesystemsinvestigated.73Avoidedgridsupplyofthesodium-nickelchloridebatteryPercentageoflossesandavoidedgridsupplytothechargedACenergyofthesodium-nickelchloridebatteryduringthesix-dayapplicationtest.74AvoidedgridsupplyofdifferentbatterytechnologiesReference:ChargedACenergyofthestoragesystemsduringthesix-dayapplicationtest.High-efficiencylithium-ionsystemscanachievevaluesofover70%comparedtothefirst-generationlithium-ionsystemstudied.75Summaryoftheresultsonthealternativebatteries•Inthe4thtopicoftheEnergyStorageInspection2023theenergyefficiencyofalternativebatterytechnologieswascomparedbyHTWBerlinandKIT.•Thelaboratorytestsshowthatthestoragelossesofthesodium-nickelchloridebatteryisseventimeshigherthanthoseoflithium-ionbattery.•Thelowchargeanddischargepowerofthesodium-ionbatteries,whichdecreasesevenfurtherwithdecreasingstateofchargealsoneedsimprovement.•Furthermore,theoverallsystemefficiencyofthealternativebatterysystemsisgreatlyaffectedbythehighACpowerconsumptionofthesystems.•Consequently,electricitystorageinsodium-ionandsodium-nickelchloridebatteriesisstillcharacterizedbysignificantlyhigherlossescomparedtostorageinlithium-ionsystems.•Improvementsareneededintermsofthematerialsused,theachievableenergydensities,thechargeanddischargepoweraswellastheconversionefficiencies.solar.htw-berlin.desolar.htw-berlin.de/inspektion