ElectricityStorageTechnologyReview

Preparedfor

U.S.DepartmentofEnergyOfficeofFossilEnergy

June30,2020

ExecutiveSummary

ElectricityStorageTechnologyReview

PAGE\*roman

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Contents

ExecutiveSummary 1

Introduction 1

ProjectOverviewandMethodology 1

WorldwideElectricityStorageInstallations 2

TheIssueatHand:LargeMarketPenetrationofIntermittentElectricityGenerationCapacity 4

ServicesProvidedbyEnergyStorageSystems 5

IndirectBenefits:Grid-ConnectedServicesProvidedbyEnergyStorage 5

DirectBenefits:IntegratingEnergyStorageDirectlywithGeneration 6

OpportunitiesforFossilThermalIntegrationwithStorage 6

TechnologyReviews 8

StationaryBatteryEnergyStorage 9

Lithium-IonBES 9

RedoxFlowBES 14

OtherBES 19

MechanicalEnergyStorage 22

CompressedAirEnergyStorage(CAES) 22

PumpedStorageHydropower(PSH) 24

ThermalEnergyStorage 27

SuperCriticalCO2EnergyStorage(SC-CCES) 27

MoltenSalt 29

LiquidAir 31

ChemicalEnergyStorage 33

Hydrogen 34

Ammonia 38

Methanol 40

ConclusionsandRecommendations 43

Bibliography 49

TableofFigures

Figure1.ComparativeMatrixwithPreliminaryAssessmentofEnergyStorageTechnologies 2

Figure2.WorldwideElectricityStorageOperatingCapacitybyTechnologyandbyCountry,2020 2

Figure3.WorldwideStorageCapacityAdditions,2010to2020 3

Figure4.IllustrativeExampleoftheImpactofPVDeploymentonGeneratorDispatch 4

Figure5.OverviewofRangeofServicesThatCanBeProvidedbyEnergyStorageSystems 5

Figure6.Co-LocatingVs.StandaloneEnergyStorageatFossilThermalPowerplantsCanProvideNetBenefitsDependingonAncillaryElectricMarketStructure 7

Figure7.IllustrativeConfigurationofaStationaryLithium-IonBES 9

Figure8.SummaryOperatingCharacteristicsofLithium-IonBES 11

Figure9.ExampleLithium-IonBESCostProjectionsIllustratingCapacityandEnergyConsiderations,

$/kW 13

Figure10.EvolutionofElectricVehicleBESCostProjectionsIllustratetheEffectsofOngoingTechnologicalChange,$/kWh 13

Figure11.ExampleConfigurationofaVanadiumRedox-FlowBES 14

Figure12.SummaryOperatingCharacteristicsofFlowBES 15

Figure13.CompaniesActiveinFlowBESCommercializationEfforts 16

Figure14IllustrativeCostProjectionsforFlowBESatDifferentHourRatings,$/kW 18

Figure15.U.S.Large-ScaleBESPowerCapacityandEnergyCapacitybyChemistry,2003-2017 19

Figure16.IllustrativeComparativeCostsforDifferentBESTechnologiesbyMajorComponent 21

Figure17.DiagramofACompressedAirEnergyStorageSystem 22

Figure18.DiagramofAPumpedStorageHydropowerStation 24

Figure19.DiagramofSuperCriticalCO2EnergyStorageSystem 27

Figure20.MoltenSaltEnergyStoragePrincipleofOperation 29

Figure21.IllustrativeIntegrationofThermalEnergyStorageintoPowerplant 29

Figure22.LiquidAirPowerCycle 31

Figure23.“Universal”BlockFlowDiagramIllustratingaMultitudeofOpportunitiesforFossilThermalPowerplantSystemstobeIntegratedwithChemicalEnergyStorage 33

Figure24.EfficienciesofFuelCellsatDifferentChemistriesandTemperatures 35

Figure25.ComparativeAssessmentofEnergyStorageTechnologies 43

Figure26.HourlyCoalPowerplantEfficiencybyLoadLevelforaRepresentativeRegionin2013-201545Figure27.FossilThermalPowerplantCharacteristics 46

Figure28.“GettingItRight”inEconomicUnitCommitmentandDispatchisKey 47

Figure29.ModelingIssues 48

NoteabouttheReview:

TheReviewisintendedtoprovideabriefingregardingarangeofenergystoragetechnologiesthatincludesadetailedlistingofprimarysources.Forthatreason,Microsoft?Word,ratherthanPowerPoint,wasusedforproducingtheReview.

ExecutiveSummary

ElectricityStorageTechnologyReview

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ExecutiveSummary

Objective:

Theobjectiveistoidentifyanddescribethesalientcharacteristicsofarangeofenergy

storagetechnologiesthatcurrentlyare,orcouldbe,undergoingR&Dthatcoulddirectlyorindirectlybenefitfossilthermalenergypowersystems.

Theusesforthisworkinclude:

InformDOE-FEofrangeoftechnologiesandpotentialR&D.

PerforminitialstepsforscopingtheworkrequiredtoanalyzeandmodelthebenefitsthatcouldarisefromenergystorageR&Danddeployment.

TechnologyBenefits:

Therearepotentiallytwomajorcategoriesofbenefitsfromenergystoragetechnologies

forfossilthermalenergypowersystems,directandindirect.

Grid-connectedenergystorageprovidesindirectbenefitsthroughregionalloadshaping,therebyimprovingwholesalepowerpricing,increasingfossilthermalgenerationandutilization,reducingcycling,andimprovingplantefficiency.

Co-locatedenergystoragehasthepotentialtoprovidedirectbenefitsarisingfromintegratingthattechnologywithoneormoreaspectsoffossilthermalpowersystemstoimproveplanteconomics,reducecycling,andminimizeoverallsystemcosts.

PreliminaryFindings:

Energystoragetechnologieswiththemostpotentialtoprovidesignificantbenefitswith

additionalR&Danddemonstrationinclude:

LiquidAir:

Thistechnologyutilizesproventechnology,

Hastheabilitytointegratewiththermalplantsthroughtheuseofsteam-drivencompressorsandheatintegration,and

Limitsstoredmediarequirements.

Ofthetwomostpromisingtechnologies,thisistheonemostreadyforimmediatedeployment.

AmmoniaProductionwithCrackingandaHydrogenFuelCell:

Forthermalintegration,thistechnologyisveryclosetoimmediatedeployment,

Eliminatestheneedforcostlycryo-storageofhydrogen,and

Itofferstheopportunityforheatintegrationandtechnologyadoptionashydrogenelectrolysisandfuelcelltechnologyisadvanced.

Figure1.ComparativeMatrixwithPreliminaryAssessmentofEnergyStorageTechnologies

Benefits

Technology

Maturity(Experience)

Durability/

Reliability(Degradation)

Duration

Capacity(hours)

Dispatch

Capacity(MW)

ResponseTime

RelativeCost

FossilThemal

Integration(Opportunity)

Better()

High

Limited

High

High

Faster

Low

High

Worse()

Limited

High

Low

Low

Slower

High

Limited

StationaryBatteryEnergyStorage

Li-IonBES

RedoxFlowBES

MechanicalEnergyStorage

CompressedAir

niche1

PumpedHydro

niche1

ThermalEnergyStorage

SC-CCES

MoltenSalt2

LiquidAir

ChemicalEnergyStorage3

Hydrogen(H2)

4

5

Ammonia(NH3)

4

Methanol(MeOH)

Source:OnLocation

Notes:

CompressedAirandPumpedHydroutilizespecificgeologicalformationswhicharenotreadilyavailabletoallfacilitylocations.

MoltenSaltisexpandedtoincludeseveralthermalstoragemediaasthecomplexityofahigh-temperaturefluid,asopposedtoastationary/solidmedia,appearstoholdlittleadditionalbenefitforfossilthermalapplication.

ChemicalEnergyStorageconsistsofseveraldifferentoptions,asdescribedinthereport.

Whileconventionalhydrogenandammoniaproductionprocessesaremature,thisreportconsidersnewertechnologiesthataremoredirectlyapplicabletofossilthermalintegration.

Conventionalhydrogenstorageisrelativelymature,howevergeologicstorageisbeingexploredandissimilartoCompressedAirstorageintechnologymaturity.

Otherpromisingtechnologiesinclude:

SuperCriticalCO2EnergyStorage(SC-CCES)

MethanolwithHydrogenFuelCell

SpecificenablingtechnologiesthatmaybenefitfromadditionalR&Dinclude:

Electrolysis(generally),

DirectMethanolFuelCell(DMFC),and

High-TemperatureSteamElectrolysis(HTSE)thatcouples800°Csteamwithsolid-oxideelectrolysistoreducetheelectricityrequirement

Energystoragetechnologiesthatarelargelymaturebutappeartohaveanichemarket,

limitedapplication,orR&Dupsideinclude:

Pumpedhydrostorage

CompressedAirEnergyStorage(CAES)

EnergystoragetechnologiesareundergoingadvancementduetosignificantinvestmentsinR&Dandcommercialapplications.

Thereexistanumberofcostcomparisonsourcesforenergystoragetechnologies

Forexample,workperformedforPacificNorthwestNationalLaboratoryprovidescostandperformancecharacteristicsforseveraldifferentbatteryenergystorage(BES)technologies(Mongirdetal.2019).

Recommendations:

Performanalysisofhistoricalfossilthermalpowerplantdispatchtoidentifyconditions

forlowereddispatchthatmaybenefitfromelectricitystorage.

Improvetechno-economicmodelingtoolstobetteraccountforthedifferentfossil

thermalpowerplantsandtheircharacteristicsandexpandtheirstoragetechnologyrepresentationstoallowforquantitativelyevaluatingthebenefitsofenergystoragebasedongridandintegrationbenefits.

Buildonthisworktodevelopspecifictechnologyparametersthatare“benched”toone

ormoreestimatesforperformanceandcost,suchasU.S.EnergyInformationAdministration(EIA),PacificNorthwestNationalLaboratory(PNNL),andothersourcesofcostestimates,thatcouldbeusedinmodelingandanalysis.

Introduction

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Introduction

ProjectOverviewandMethodology

Theobjectiveofthisworkistoidentifyanddescribethesalientcharacteristicsofarangeofenergystoragetechnologiesthatcurrentlyare,orcouldbe,undergoingresearchanddevelopmentthatcoulddirectlyorindirectlybenefitfossilthermalenergypowersystems.

Theresearchinvolvesthereview,scoping,andpreliminaryassessmentofenergystoragetechnologiesthatcouldcomplementtheoperationalcharacteristicsandparameterstoimprovefossilthermalplanteconomics,reducecycling,andminimizeoverallsystemcosts.

Thereportprovidesasurveyofpotentialenergystoragetechnologiestoformthebasisforevaluatingpotentialfuturepathsthroughwhichenergystoragetechnologiescanimprovetheutilizationoffossilfuelsandotherthermalenergysystems.

Theworkconsistedofthreemajorsteps:

Aliteraturesearchwasconductedforthefollowingtechnologies,focusingonthemostup-to-dateinformationsourcesavailable:

Stationarybatteryenergystorage(BES)

Lithium-ionBES

RedoxFlowBES

OtherBESTechnologies

MechanicalEnergyStorage

CompressedAirEnergyStorage(CAES)

PumpedStorageHydro(PSH)

ThermalEnergyStorage

SuperCriticalCO2EnergyStorage(SC-CCES)

MoltenSalt

LiquidAirStorage

ChemicalEnergyStorage

Hydrogen

Ammonia

Methanol

Eachtechnologywasevaluated,focusingonthefollowingaspects:

Keycomponentsandoperatingcharacteristics

Keybenefitsandlimitationsofthetechnology

Currentresearchbeingperformed

Currentandprojectedcostandperformance

Researchandcommercializationstatusofthetechnology

Acomparativeassessmentwasmadeofthetechnologiesfocusingontheirpotentialforfossilthermalpowerplantintegrationinthenearterm(i.e.,commerciallyavailable)aswellasinthelongerterm(i.e.,opportunitiesforadditionalresearch,demonstrationanddevelopment).

WorldwideElectricityStorageInstallations

Figure2.WorldwideElectricityStorageOperatingCapacitybyTechnologyandbyCountry,2020

Source:DOEGlobalEnergyStorageDatabase(Sandia2020),asofFebruary2020.

Worldwideelectricitystorageoperatingcapacitytotals159,000MW,orabout6,400MWifpumpedhydrostorageisexcluded.TheDOEdataiscurrentasofFebruary2020(Sandia2020).

Pumpedhydromakesup152GWor96%ofworldwideenergystoragecapacityoperatingtoday.

Oftheremaining4%ofcapacity,thelargesttechnologysharesaremoltensalt(33%)andlithium-ionbatteries(25%).FlywheelsandCompressedAirEnergyStoragealsomakeupalargepartofthemarket.

Thelargestcountryshareofcapacity(excludingpumpedhydro)isintheUnitedStates(33%),followedbySpainandGermany.TheUnitedKingdomandSouthAfricaroundoutthetopfivecountries.

Figure3.WorldwideStorageCapacityAdditions,2010to2020

Source:DOEGlobalEnergyStorageDatabase(Sandia2020),asofFebruary2020.

Excludingpumpedhydro,storagecapacityadditionsinthelasttenyearshavebeendominatedbymoltensaltstorage(pairedwithsolarthermalpowerplants)andlithium-ionbatteries.

AbouthalfofthemoltensaltcapacityhasbeenbuiltinSpain,andabouthalfoftheLi-

ionbatteryinstallationsareintheUnitedStates.

Redoxflowbatteriesandcompressedairstoragetechnologieshavegainedmarketshareinthelastcoupleofyears.Themostrecentinstallationsandexpectedadditionsinclude:

A200MWVanadiumRedoxFlowBatterycameonlinein2018inDalian,China.

A300MWcompressedairfacilityisbeingbuiltbyPG&EinCalifornia–estimatedonline

dateis2020.

TheIssueatHand:LargeMarketPenetrationofIntermittentElectricityGenerationCapacity

Figure4.IllustrativeExampleoftheImpactofPVDeploymentonGeneratorDispatch

Source:OnLocationusingresultsfromtheNEMSREStoreModel

Recentandprojectedfutureelectricitygeneratingcapacityisexpectedtobeincreasinglynon-dispatchablerenewable,especiallysolarPV,leadingtosqueezingofothergeneratingsources.

Inaddition,mostfossilthermalpowerplantslackthecapabilitytoquicklyrampdowngenerationwhenthesunrisesandrampupwhenthesunsetsbecauseofthermalcyclinglimitations.

Therepresentative24-hourloadprofileshowninFigure4wascreatedusingresultsoftheEIANEMSREStoremodel1.ThisprofileillustratessomeofthechallengesfacingfossilthermalplantdispatchinregionswithlargedeploymentofPV’sonthegrid.

AssolarPVgeneration(shownastheredbarsinthechart)rampsupduringthemid-day

hours,coalgeneration(pinkbars)issqueezedoutofthegenerationmix.

Likewise,asPVgenerationrampsdowninthelateafternoonhours,coalgenerationlevelsaregraduallyrestoredtobaseloadlevels.

Solargenerationthatexceedsthesystemloadrequirement(blueline)iscapturedand

storedbythesystem’sstoragecapacityandisthendischarged(brownbars)duringtheshoulderhourswhensolargenerationisnotavailable.

Fossilthermalplantsthathaveonsitestoragecapabilitycouldstoreexcessgenerationinthemid-dayhourstoreducetheneedtorampdownduringthosehours.Thestoredelectricitycouldthenbedischargedduringhourswhensolarisnolongeravailable,especiallyinregionswithpeakhoursthatoccurlaterintheday.Thiswouldincreasethetotalgenerationand

efficiencyofthefossilplant,therebyreducingtheneedtocycleanditsassociatedcosts.

1FormoreinformationabouttheEIANEMSREStoremodel,seeEIA“AssumptionstotheAnnualEnergyOutlook2020:ElectricityMarketModule,”https://

/outlooks/aeo/assumptions/pdf/electricity.pdf.

ServicesProvidedbyEnergyStorageSystems

Energystoragesystemscanprovideindirectanddirectbenefitstofossilthermalpowerplants.

IndirectBenefits:Grid-ConnectedServicesProvidedbyEnergyStorage

Figure5.OverviewofRangeofServicesThatCanBeProvidedbyEnergyStorageSystems

Source:(InternationalRenewableEnergyAgency2017)

Electricitystoragesystemscanprovideawiderangeofservicestogenerators,utilities,andcustomerswhenconnectedtoapowergrid:

Generationorbulkenergyservices

Energytime-shifting/generationarbitrageinvolvesgeneratingorpurchasingelectricity

attimeswhenelectricityratesarelowandstoringthatelectricityforsalelaterwhenratesarehightoreducecostsand/ormaximizerevenues.

Electricsupplycapacityandpeakdemandmanagementprovidessupportattimesof

peakdemandbystoringelectricityatoff-peakhoursanddischargingwhendemandishighest.Thisallowsutilitiestodeferoreliminatetheneedforbuildingadditionalpeakingcapacitysuchascombustionturbines.

Capacityfirming/smoothingallowsgeneratorstomaximizetheavailabilityoftheir

generation.

Forbaseloadplants,storagesystemscanstoreelectricityduringperiodsoflowdemand(orhighnon-dispatchablegenerationsuchassolarPV)whenbaseloadplantswouldnormallyrampdowntheirgeneration,allowingtheseplantstooperateatahigherlevel.Similarly,duringperiodsofhighdemandwhenplantsneedtorampupgeneration,storedelectricitycanbereleasedtoreducethedemandforcycling.Alsoknownasloadfollowing,energystoragecanresultislesscycling,whichcanreduceoperatingcosts,increaseplantefficiency,andextendplantlifetime.

Forrenewableplants,storagesystemscanbeusedtocapturesolarandwindgenerationthatmayexceeddemandduringcertainhoursoftheday,thusreducingtheneedtocurtailgeneration.Thestoredelectricitycanthenbedischargedduringthe“shoulder”hourstosmoothoutgeneration,especiallyforsolargenerationthatrampsupquicklyasthesunrisesandrampsdownquicklyasthesunsets,puttingastrainontheelectricsystem.

Gridservices

AncillaryServicesprovidethenecessarysupportforthetransmissionofelectricpower

fromsellertopurchasertomaintainreliableoperationsoftheinterconnectedtransmissionsystem.Examplesincludefrequencyregulation,voltagecontrol,blackstartsupport,andspinning,non-spinningandsupplementalreserves.

Transmissionanddistributionupgradescanbedeferredtoreducesystemcosts

Transmissioncongestioncanberelievedbyplacingstoragesystemsinstrategic

locationsalongcongestedtransmissionlines.Thisreducescongestionchargesandthepotentialforsupplydisruptions.

Behindthemeter

Storagesystemscanbeusedbycustomerstoprovidebackuppowerforreliability,

demandshiftingtoreduceelectricitybills,anddemandchargemanagementtoreducetheiraveragepeakloadanddemandcharges(Hewettetal.2016).

Storagetechnologieshavedifferentattributesthatmakethemmoresuitableforonetypeofserviceoveranother.Attributessuchasstoragecapacityandduration,responsetime,round-tripefficiency,cost,andexpectedlifetimeplayaroleindeterminingthebestapplicationforeachtechnology.

DirectBenefits:IntegratingEnergyStorageDirectlywithGeneration

Integratingenergystoragedirectlywithgeneration,alsoknownas“hybridenergystorage,”arepowerplantswithon-sitestorage.

Manysolarplantshavechosentobuildon-sitestorage,includingPVplantspairedwithbatteriesandsolarthermalplantspairedwiththermalstoragesuchasmoltensalt.

NRELestimatesthatco-locatingLi-Ionbatteryenergystorage(BES)withaPVsystemwouldsaveupto8%incapitalcosts(Fu,Remo,andMargolis2018)duetosavingsarisingfrom:

Siteacquisition,preparation,andpermitting,

Sharedswitchgear,transformer,andcontrolequipment,

Installationlabor,overheadandprofit.

OpportunitiesforFossilThermalIntegrationwithStorage

Thermalstoragetechnologiesareabletostorewasteheatproducedbythefossilpowerplantanduseittodriveaturbineandsupplementthefossilplant’sgenerationduringpeakhours.

Chemicalstoragetechnologiescanusethewasteheatforchemicalprocessessuchashigh-temperatureelectrolysisandammoniacracking.

Batterytechnologiescanstoreexcesselectricityproducedbythefossilpowerplanttomaximizegenerationduringpeakandoff-peakhours.

Otherbenefitsfromfossil/storageintegrationinclude:

Sharedinfrastructuresuchastransformersandtransmissionlines,thusreducingthe

investmentrequiredforinstallation.

Reducedthermalgeneratorcyclingreduceswearandtearontheequipmentandimprovestheplant’sheatrate.

Storagetechnologiescanprovideancillaryservicesthatcannotbemetbyfossilthermal

technologies,providinganadditionalsourceofrevenue.

Figure6.Co-LocatingVs.StandaloneEnergyStorageatFossilThermalPowerplantsCanProvideNetBenefitsDependingonAncillaryElectricMarketStructure

Source:(Sejatietal.2019)

Co-locatingenergystoragewithneworexistingfossilplantscanalsosavemoneyandincreasethevalueofthefossilplantthroughthesamebenefitsasdescribedabove.Inaddition,benefitscanarisefrom:

Greaterutilizationofenergythatmayotherwisebecurtailedduringperiodsoflow

demandandutilizethatunit’selectricityorsteamoutputtoproduceanalternative,marketable,product.

Reducedwearandtearfromthermalgeneratorcycling(Gormanetal.2020).

Improvedheatrateduetolesscycling,asdepictedabove.

Betterreturnsoninstalledcapacityifelectricpowermarketsarenotadequately

compensatingfossilthermalpowerplantsfortheircontributiontotheelectricgrid.

TechnologyReviews

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TechnologyReviews

Thissectionreviewstheliteratureonenergystoragetechnologiesandsummarizeseachasfollows:

TechnologyDescription

TechnologyBenefitsandLimitations

TechnologyStatusincludingresearchopportunities

TechnologyCostProjections

Inperformingtheworkitwasfoundthatthetechnologiescanbeorganizedbycategory,asfollows:

StationaryBatteryEnergyStorage

MechanicalEnergyStorage

ThermalEnergyStorage

ChemicalEnergyStorage

TechnologyReviews

StationaryBatteryEnergyStorage–Lithium-IonBES

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StationaryBatteryEnergyStorage

Lithium-IonBES

TechnologyDescription

Figure7.IllustrativeConfigurationofaStationaryLithium-IonBES

LithiumIonBattery

Cathode

Li+

Li+

discharge

Li+

Li+

Li+

Li+

Li+

charge

Anode

DirectCurrent

PowerConversionSystem(PCS)

DCACDCAC

Grid

Li+

Li+

Electrolyte(medium)

Separator

Source:OnLocation

AstationaryBatteryEnergyStorage(BES)facilityconsistsofthebatteryitself,aPowerConversionSystem(PCS)toconvertalternatingcurrent(AC)todirectcurrent(DC),asnecessary,andthe“balanceofplant”(BOP,notpictured)necessarytosupportandoperatethesystem.

Thelithium-ionBESdepictedinError!Referencesourcenotfound.illustratesthecathodeandanodeindischargemode(duringchargingtheelectrodesarereversed):

Charging:Powerisappliedtothebatterybyprovidingahighervoltageatthepositive

electrode,whichinduceslithiumionstobedisplacedfromthatelectrodethatthentransportthroughtheelectrolyte,throughtheseparator,andarethencollectedwithinthenegativeelectrode.

Discharging:Powerisextractedthroughreversingtheprocessbyapplyingaloadonthe

battery.

Thedischarge/chargecycleleadstothesebatteriesbeingreferredtoas“rockingchairbatteries.”

Thebatteryisaself-containedstoragedevicethatissizedinawaythatconsiders:

Dischargehours(MWh),

Maximumrequiredoutput(MW),and

Designlifeofthebattery(numberofcycles),whichisafunctionofbatterychemistry,

expectedutilization,andageofthebattery.

ThePCSscaleswiththemaximumratedBESoutputcapacity,measuredinkW.

Thefirstbatterieswereusedforconsumerelectronicssuchascellularphonesbuttheyhavenowbeenscaledforuseinelectricvehiclesandlarge-scalegridstorageapplications.

Li-ionbatterycellsconsistofagraphiteanode,metal-oxidecathode,andalithiumsaltelectrolytegel.Forstationarystorageapplications,thesecomponentsarepackagedinapouchorotherconfiguration.Batterycellsareintegratedintobatterymodules,whichareinstalledinstandard19-inch-wideracksinabuildingorspecializedcontainertocreateanintegratedbatterysystem(Aquinoetal.2017).

Theterm“l(fā)ithium-ion”referstoavarietyofdifferentchemistries,allofwhichoperatebytransferringlithiumionsbetweentheelectrodesduringthechargeanddischargereactions.Lithium-ioncellsdonotcontainmetalliclithium;instead,theionsareinsertedintoothermaterialssuchaslithiatedmetaloxidesorphosphatesinthepositiveelectrode(cathode)andcarbon(suchasgraphite)orlithiumtitanateinthenegativeelectrode(anode)(EnergyStorageAssociation,n.d.).

Theprimarychemistriesinusetodayare:

Lithiumnickelmanganesecobaltoxide(NMC)

Lithiummanganeseoxide(LMO)

Lithiumironphosphate(LFP)

Lithiumtitanate(LTO)

NMCarethemostpopularchemistriesingrid-scalestoragesystemsbecausetheydemonstratebalancedperformancecharacteristicsintermsofenergy,power,cost,andcyclelife.

Li-ionbatteriesarehighlysensitivetotemperature.Thebuildingorcontainerhousingthebatterysystemtypicallyincludesanactivecoolingsystemtoensurethebatteriesstaywithinanoptimaltemperaturerangeofaround70°F(Aquinoetal.2017).

TechnologyBenefitsandLimitations

Figure8.SummaryOperatingCharacteristicsofLithium-IonBES

Source:(Kimetal.2018)

Benefits:

LowCost:Lithium-ionbatterycostshavedeclineddramaticallyinrecentyears,asmuchas80%between2010and2017(DeloitteCenterforEnergySolutions2018).Thisdeclineisdueinparttosynergieswiththescaleofmanufacturingandresearchinotheruses,includinginelectricvehiclesandelectronics.

Operatingcharacteristics:

Veryfastresponserates(afractionofasecond)makingthemgoodcandidatesforgrid

balancingservices

Flexiblesizesandshortconstructiontimes.Forexample,“In2017,Teslabuilta

100MW/130MWhcontainerizedlithium-ionstoragesysteminAustraliawithinjustthreemonths.”(Kairies,Figgener,andHaberschusz2019).

Highlyefficient,generallyrangingfrom85%to95%efficiency(Zablocki2019).

Dischargetimesof1secondtoupto8hours

Comparedtootherbatteryoptions,lithium-ionbatterieshavehighenergydensityand

arelightweight.

Regulatoryincentives:

BatteryinstallationsaregrowingrapidlyinthemanyU.S.statesthathavestoragegoals,

mandates,andincentives.AccordingtotheU.S.EIAAnnualEnergyOutlook2020,statemandatesalonetotalmorethan6,500MWby2030.

Almosteverynationischangingitswholesalemarketrulestoallowbatteriesto

competeforcapacityandancillaryservices,suchasfrequencyregulationandvoltagecontrol(DeloitteCenterforEnergySolutions2018).

Limitations:

“Duetothetemperaturesensitivity,firehazard,andspecialshippingrequirements,manystatesclassifystationaryLi-ionsystemsashazardousmaterials.”(Aquinoetal.2017)

Reportsofpoliticalunrestandhumanrightsabuses,includingchildlabor,relatedtocobaltminingintheDemocraticRepublicofCongowhichaccountsforroughly60percentofglobalproductionofcobalt(e.g.,Barrera2020).

Environmentalaspectsrelatedtoveryexpensiverecyclingofthemanyhazardoussubstances(cobalt,nickel,organicelectrolytes)(Noacketal.2019).

Poorscalabilityforhighenergy(longduration)applications

Notalllithiumbatterychemistriesusecobalt.TeslaannouncedinFebruary2020th