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hRM

Powering

Through

Uncertainty

AResourceAdequacyToolkitforWesternRegulators

Brief/November2024

AuthorsandAcknowledgments

Authors

AshtinMassie

AaronSchwartz

LaurenShwisberg

Authorslistedalphabetically.AllauthorsarefromRMIunlessotherwisenoted.

RMIContributors

StephanieBielerTylerFarrell

KaterinaStephanSarahToth

ClaireWayner

BrookeJin(formerintern)

Contacts

AshtinMassie,amassie@

LaurenShwisberg,lshwisberg@

CopyrightsandCitation

AshtinMassie,AaronSchwartz,andLaurenShwisberg,PoweringThroughUncertainty:AResourceAdequacyToolkitforWesternRegulators,RMI,2024,

/insight/powering-through-uncertainty-a

-

resource-adequacy-toolkit-for-western-regulators.

RMIvaluescollaborationandaimstoacceleratetheenergytransitionthroughsharingknowledgeand

insights.Wethereforeallowinterestedpartiestoreference,share,andciteourworkthroughtheCreativeCommonsCCBY-SA4.0license.

/licenses/by-sa/4.0/

.

AllimagesarefromRMIunlessotherwisenoted.

Acknowledgments

ThisworkismadepossiblewithsupportfromtheHeising-SimonsFoundation.Theauthorsthankthefollowingindividualsforgraciouslyofferingtheirinsightstothiswork.Inclusiononthislistdoesnotindicateendorsementofthereport’sfindings.

•AmandaOrmond,WesternGridGroup

•BenFitch-Fleischmann,InterwestEnergyAlliance

•HeidiRatz,CleanEnergyBuyersAssociation

•KarlBoothman,SydneyWelter,WesternResourceAdvocates

•KateBowman,VoteSolar

•KatieChamberlain,RenewableNorthwest

•MarkSpecht,UnionofConcernedScientists

PoweringThroughUncertainty:AResourceAdequacyToolkitforWesternRegulators/2

hRM

AboutRMI

RMIisanindependentnonprofit,foundedin1982asRockyMountainInstitute,thattransformsglobalenergysystemsthroughmarket-drivensolutionstoalignwitha1.5°Cfutureandsecureaclean,

prosperous,zero-carbonfutureforall.Weworkintheworld’smostcriticalgeographiesandengage

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PoweringThroughUncertainty:AResourceAdequacyToolkitforWesternRegulators/3

TableofContents

ExecutiveSummary 6

Introduction 9

DriversofResourceAdequacyUncertainty 14

LoadGrowthUncertainties 15

ExtremeWeatherandClimateChange 17

DelaysinPlannedResourceBuilds 19

SlowTransmissionExpansion 20

RegulatoryStrategiestoUnlockanAffordable

andLow-CarbonResource-AdequateGrid 22

Strategy#1:ImprovePlanningPracticestoReflectModernDriversofRisk 22

Ensurethatutilitiesconducttargetedanalysestothoroughlyevaluateemergingdriversofrisk 23

Incorporatestakeholderinputonreliabilityconcerns,risks,andneedsintotheplanningframework25

Applyanexpandedandcomprehensivesetofmetricstoevaluateriskinplanning 28

Strategy#2:BroadentheSetofTechnologiesandEnergySolutionsThatCanSupport

ResourceAdequacyintheShortandLongTerm 30

Ensurethatquick-to-deploydemand-sideresourcessuchasvirtualpowerplants

arebeingdevelopedandleveragedtosupportresourceadequacy 32

Leveragecleanrepoweringtofast-trackdeploymentofsupply-sideresources 34

Requireutilitiestoevaluatetheroleofdeliveryoptionstosupportresourceadequacy,

includingwithgridmodernization,transmission,andregionalcoordination 35

Requireutilitiestoevaluatethepotentialofemergingtechnologieswithlongerleadtimesto

supportresourceadequacy 37

Strategy#3:PursueUtilityBusinessModelReformsThatCanSupport

ResourceAdequacy 38

Transformutilityincentivestoencouragecost-effectiveandlow-carbonresourceadequacy

investments 40

Exploreratemakingstructuresthatincentivizecustomerconsumptionchangesthatcan

improveresourceadequacy 43

Openthedoortoprogramsandtariffsthatsupportcustomerprocurementofcleanenergy.45

Conclusion 48

Endnotes 49

Abbreviations

CAGRCompoundannualgrowthrate

CAISO

CaliforniaIndependentSystemOperator

CEBA

CleanEnergyBuyersAssociation

CPUC

CaliforniaPublicUtilitiesCommission

DER

Distributedenergyresource

DOE

DepartmentofEnergy

DSGS

DemandSideGridSupport

EIA

EnergyInformationAdministration

ELRP

EmergencyLoadReductionProgram

FERC

FederalEnergyRegulatoryCommission

GW

Gigawatt

HPUC

HawaiiPublicUtilitiesCommission

IRP

Integratedresourceplan

ISO

Independentsystemoperator

LDES

Long-durationenergystorage

LOLELossofloadexpectation

MWMegawatt

NERC

NorthAmericanElectricReliabilityCorporation

NWPCC

NorthwestPowerandConservationCouncil

PBR

Performance-basedregulation

PIM

Performanceincentivemechanism

PNM

PublicServiceCompanyofNewMexico

RA

Resourceadequacy

RFI

Requestforinformation

RFP

Requestforproposals

SPS

SouthwesternPublicServiceCompany

TOU

Time-of-use

VPP

Virtualpowerplant

WECC

WesternElectricityCoordinatingCouncil

WRAP

WesternResourceAdequacyProgram

PoweringThroughUncertainty:AResourceAdequacyToolkitforWesternRegulators/5

ExecutiveSummary

Resourceadequacy(RA)—thecomponentofgridreliabilityfocusedonensuringenoughpowersupplyisavailableinthelongtermtomeetdemandunderarangeoffutureconditions—hascomeunderincreasedscrutinyfromregulatorsastraditionalfossilfuelpowerplantsapproachretirementatthesametime

aselectricitydemandisforecastedtogrow.Regulatorsacrossthecountryhaveanobligationtoensure

affordable,reliableelectricalservicetoutilitycustomers,andthereforemustbeabletonavigateemergingRAchallengeswhilepresidingoverahistorictransformationoftheelectricalgrid.

ThisreportaimstosupportWesternregulators—whooverseegridplanningthroughutility-by-utility

processesandaretaskedwithensuringthatutilityplanssupportsafety,affordability,andreliability—inunderstandingboththekeydriversofRAriskandthespecificoptionsavailabletonavigateandmitigatethisuncertaintyasthegridevolves.

WeidentifyfourprimarydriversofRAriskfacingWesternstatesi(seeExhibitES1,nextpage):load

growthuncertainties,extremeweatherandclimatechange,delaysinplannedresourcebuilds,andslowtransmissionexpansion.

iHere,WesternstatesincludeArizona,California,Colorado,Idaho,Montana,Nevada,NewMexico,Oregon,Utah,Washington,andWyoming.BecauseHawaiiandAlaskaarealsomemberstatesoftheWesternConferenceofPublicServiceCommissioners,weincluderelevantexamplesandcasestudiesfromthosestates,althoughtheyareexcludedfromstatisticsanddatareferringtotheWestandWesternstates.

PoweringThroughUncertainty:AResourceAdequacyToolkitforWesternRegulators/6

ExhibitES1DriversofresourceadequacyuncertaintyintheWest

Uncertaintiesaroundthescale,

timing,andtypeofloadgrowth

fromresidential,commercial,

andindustrialelectrification

Transmissionconstraintsthatisolate

utilitysystemsandlimitthegrowth

ofnewgenerationresources

Extreme

weatherand

climatechange

Delaysingettingnewresourcesonline,primarilystemming

fromconstructionandinterconnection

RMIGraphic.

LoadGrowthUncertainties–AcrosstheWest,utilitiesareprojectingdemandtoincreasebeyondhistoricrates,primarilydrivenbyelectrificationofendusessuchasheatingandtransportationandtheadditionoflargeelectricloadsfromdatacentersandotherindustrialconsumers.However,theseforecastsarehighlyuncertain,makingitmoredifficulttocost-effectivelyplanforRA.

ExtremeWeatherandClimateChange–AlsoacrosstheWest,utilitiesandcustomersarealready

experiencingsocietalandeconomiceffects,includingwithlocalpoweroutages,fromtheincreased

frequencyandmagnitudeofextremeweatherevents.Extremeeventsincludingheatwaves,coldsnaps,

drought,wildfires,andotherseverestormsarebecomingmorefrequentandmorecostly.Thewayinwhichextremeweathertrendswillevolveisuncertain,andsomanagingthesethreatsremainsachallengefor

long-termRAplanningandoutcomes.

DelaysinPlannedResourceBuilds–Delaysinconstructionrelatedtotradebarriers,supplychainissues,

permittingholdups,andotherregulatorychallengesacrosstechnologieshavebeenincreasingproject

timelinesandcompletionuncertainty.Nationwidein2023,over38gigawatts(GW)ofcleanpowerexperiencedprojectdelays.1Simultaneously,lengthyinterconnectionprocesseshavecreatedbacklogsofresourceswaitingtoconnecttothegridacrossthecountry.Attheendof2023,thenon-ISO(IndependentSystemOperator)West(whichexcludestheCaliforniaIndependentSystemOperator[CAISO]footprint)hadover700GWofcapacitywaitingtointerconnecttothegrid,whileCAISO’sinterconnectionqueuehadover500additionalGW.2

SlowTransmissionExpansion–CurrentutilityplansintheWestarenotkeepingpacewithregional

andinterregionaltransmissionneedstosupportthegridunderawiderangeofresourceandloadgrowthscenarios.Forexample,theMountainWestandSouthwestregionsareseeingneedstodoubletotriplethesizeofwithin-regiontransmissionby2035tosupportnewresourcedevelopmentanddemandgrowth,

whileinterregionaltransfercapacitiesmayneedtoincreasebyasmuchas25GWoverthesameperiod.3

TransmissionhasthepotentialtoimproveRAoutcomesacrosstheWest,andconstraintsindevelopmentofbothregionalandinterregionaltransmissioncancauseRAbenefitstobeleftoffthetable.

PoweringThroughUncertainty:AResourceAdequacyToolkitforWesternRegulators/7

Fortunately,WesternregulatorscanpursuethreekeystrategiestoanticipateandmitigatetheprimarydriversofRAuncertaintyinwaysthatarecompatiblewithacost-effectivetransitiontoalow-carbongrid(seeExhibitES2).Bypursuingimprovementsinplanningpractices,wideningthesuiteofRAsolutions,andseekingreformsinutilitybusinessmodels,regulatorscanreducetheriskoffutureRAshortfalls

whilecontinuingtofacilitateatransitiontoalow-carbongridthatbenefitscustomersandenableslocaleconomicdevelopment.

ThisreportfurtherelaboratesontheRArisksfacingWesternstates,optionsregulatorscanpursueto

mitigatetheserisks,andkeyactionsregulatorscantaketoreduceRAshortfallsfortheircustomers

(FigureES-2).Foramorein-depthsummaryoftheseactions,seeExhibits11(page23),13(page31),and15(page39).

ExhibitES2Optionsforregulatorstocost-effectivelysupportresourceadequacyduringthetransitiontoalow-carbongrid

Improveplanning

•Ensurethatutilitiesconducttargetedanalysestothoroughlyevaluate

practicestoreflect

emergingdriversofrisk.

moderndriversofrisk

•Incorporatestakeholderinputonreliabilityconcerns,risks,andneedsintotheplanningframework.

•Applyanexpandedandcomprehensivesetofmetricstoevaluateriskinplanning.

Broadenthesetof

•Ensurethatquick-to-deploydemand-sideresourcessuchasvirtual

technologiesand

powerplantsarebeingdevelopedandleveragedtosupportresource

energysolutionsthat

adequacy.

cansupportresourceadequacyintheshort

•Leveragecleanrepoweringtofast-trackdeploymentofsupply-sideresources.

andlongterm

•Requireutilitiestoevaluatetheroleofdeliveryoptionstosupportresourceadequacy,includingwithgridmodernization,transmission,andregionalcoordination.

•Requireutilitiestoevaluatethepotentialofemerginglonglead-timetechnologiestosupportresourceadequacy.

Pursueutilitybusiness

•Transformutilityincentivestoencouragecost-effectiveandlow-carbon

modelreformsthat

resourceadequacyinvestments.

cansupportresourceadequacy

•Exploreratemakingstructuresthatincentivizecustomerconsumptionchangesthatcanimproveresourceadequacy.

•Openthedoortoprogramsandtariffsthatsupportcustomerprocurementofcleanenergy.

RMIGraphic

PoweringThroughUncertainty:AResourceAdequacyToolkitforWesternRegulators/8

Introduction

TheWesternelectricgridisundergoingarapidtransformationtowardlow-carbonenergyresources.In

thepastdecade,24gigawatts(GW)ofcoalandgashaveretiredinWesternstates,whilesolar,wind,and

batterystoragehavegrownby55GW,drivenbycompetitivecleanenergyeconomicsandstateandfederalclimatepolicy.4Expertsexpectthebuild-outoftheseresourcestocontinue:solar,wind,andbatterystoragerepresentmorethan80%ofthe121GWofplannedresourceadditionsacrosstheWest.5Moreover,nearly10timesthatamounthavestartedtheinterconnectionapprovalprocesstoconnecttothegrid,suggestingthescaleofthegridtransformationcomingtoWesternstates.6

SeveralanalyseshaveshownthattheWesthasthepotentialtomeetambitiouscleanenergygoalsassoonas2030withoutsacrificingresourceadequacy.7Resourceadequacy(RA)isonecomponentofgridreliabilityfocusedonensuringenoughgenerationresourcesareavailableonthegridinthelongtermtomeetfutureloadacrossvariousconditions,whileaccountingforuncertaintyingenerationandload(seeResource

adequacyandreliabilityonfollowingpageformoredetail).8

Exhibit1CapacitytransitioninWesternstates

From2012to2023,Westernstateshaveseenastrongbuild-outofcarbon-freeenergyresources,whichhasacceleratedinrecentyearsandsupportedtheretirementofagingfossilfuelplants.

Change,2012–15

Change,2016–19Change,2020–23

200GW

150

100

50

0

2012AdditionsRetirements20232012AdditionsRetirements2023

CARBON-FREEGWFOSSILGW

Note:Carbon-freeenergyresourcesincludewind,solar,batterystorage,hydro,geothermal,nuclear,andbiomass.RMIGraphic.Source:S&PGlobal

PoweringThroughUncertainty:AResourceAdequacyToolkitforWesternRegulators/9

Resourceadequacyandreliability

Maintaininggridreliabilitymeanskeepingthelightsonforcustomers,butdoingsoisacomplexprocessthatspansboththebulkpowersystem—thehigh-voltageregionalgridthatbringspowerfrompowerplantstolocalutilities—andthedistributionsystem—thelocalgridthatsupplies

thatpowertohomesandbusinesses.9Toensureatrulyreliablegrid,plannerslooktominimizeshortfallsacrossallaspectsofthegridsystem,describedinExhibit2.

Exhibit2Gridreliabilitycomponentsdefined

DistributionsystemBulkpowersystem

Theabilityoftheelectricitysystemtosupplytheaggregate electricaldemandandenergyrequirementsoftheend-use

Theabilityofthe

distributionsystemtodeliverelectricitytoend-users(suchashomesand

businesses).

Distributionsystem

reliability

Resourceadequacy

customersatalltimes, takingintoaccount scheduledandreasonablyexpectedunscheduledoutagesofsystemelements.

Theabilityto

withstandandreduce

themagnitudeand/ordurationofdisruptiveevents,whichincludestheabilitytoanticipate,absorb,adaptto,and/or

rapidlyrecoverfromsuch

anevent.

Theabilityofthe

Operationalreliability

Resilience

ofsystemelementsfrom crediblecontingencies,while avoidinguncontrolledcascadingblackoutsordamagetoequipment.

bulkpowersystemto withstandsudden disturbances,suchaselectricshortcircuitsortheunanticipatedloss

RMIGraphic.Source:NationalRenewableEnergyLaboratory,

/docs/fy24osti/85880.pdf

;NorthAmericanElectricReliabilityCorporation,

/AboutNERC/Documents/Terms%20AUG13.pdf

;andElectricPowerResearchInstitute,

/research/products/000000003002014963

.

Whilethetermgridreliabilityisoftenbroadlyapplied,itisimportantthatsolutionstoreliability

challengestargetspecificreliabilitycomponents.Thiswillensureplannersareaddressingspecificrisksacrossthesystemthatcouldleadtocustomeroutages,andthatutilitiesarebuildingoutthemostcost-effectivesolutionsetthatcanaddressthespecificreliabilitychallengestheyface.For

example,themostcost-effectiveoptionstoimprovedistributionsystemreliabilityarelikelya

differentsetofsolutionsthanthosebestsuitedtosupportRA.Withoutspecificityindescribingtheproblem,resourcesproposedtobroadlyimprovegridreliabilitymaynotprovidethemosteffectivereliabilityimprovements,especiallyrelativetotheircost.

Today,mostcustomeroutagesresultfromlocaloutagesonthedistributionsystem,butsupply-sideoutagesstemmingfromRAshortfallscanbedangerousandcostly,whichiswhytargeted

solutionsforRAchallengesareessentialasemergingsupply-sidethreatsbecomemoretangible.

PoweringThroughUncertainty:AResourceAdequacyToolkitforWesternRegulators/10

Lookingforward,emergingexternalforces,coupledwiththeeconomicretirementsoftraditionalfossil

fuelpowerplants,areaddingcomplexityanduncertaintytomaintainingaresource-adequategrid.As

such,RAisanessentialtopicforregulatorstoprioritizetoday.WhilemanyentitiesdoRAassessmentsandplanningacrosstheWest,theroleoftheregulatorisincreasinglyanduniquelyimportant—especiallynow,asregulatorsarealsopresidingoverahistorictransformationoftheelectricalgrid(seeHowisresource

adequacyevaluatedintheWesttoday,andwhatarestateregulators’roles?).Regulatorshaveanobligationtoensureutilitiesareprovidingbothreliableandaffordableelectricalservicetocustomers,andthereforemustbeabletonavigateemergingRAchallengeswhilealsomanagingcosts.

HowisresourceadequacyevaluatedintheWesttoday,andwhatarestateregulators’roles?

UtilitiesintheWesttypicallydevelopintegratedresourceplans(IRPs),usedforlong-termsystem

planning,toensuretheirsystemisresourceadequate.Duringtheintegratedresourceplanning

process,whichusuallyoccurseverythreetofiveyears,utilitiestypicallyrelyonacombinationofgridplanningmodels,suchascapacityexpansionandRAmodels,toensuretheyareplanningforbothaneconomicallyoptimalandresource-adequatesystemacrossarangeofpotentialfutureconditions.Outcomesfromthismodelingthendriveutilityprocurementdecisions.

AlthoughRAevaluationswithinintegratedresourceplanningprocessesareessentialforutility-

specificplanning,regionalRAevaluationsarealsonecessarytogainabig-pictureperspectiveofRA,complementingtheassessmentsfromanindividualutility’sIRP.RegionalRAevaluationsensurethatutilitiesarenotrelyingonregionalresourcesoutsideoftheirfootprintsthatmayultimatelynotbeavailable,andtheyprovideinsightintoregionaltrendsandrisksthatmayimpactlocalutilityplansinthefuture.RegionalRAassessmentsalsoassessutilitysystemsunderaconsistentandunifying

methodology,unlikeindividualutilityIRPs,whichcanusevaryingmethodologiestoassessRA.NumerousagenciesconductdifferenttypesofregionalRAassessmentsintheWest:10

PoweringThroughUncertainty:AResourceAdequacyToolkitforWesternRegulators

/11

•Atthefederallevel,theNorthAmericanElectricReliabilityCorporation(NERC)develops

seasonalandlong-term(lookingout10years)RAassessmentsofthebulkpowersystem,

releasedannuallyanddevelopedusinginputsfromitssixregionalentitiestaskedwithensuringNERCReliabilityStandards.11

•TheWesternElectricityCoordinatingCouncil(WECC),theregionalentitytaskedwithenforcing

NERCstandardsintheWest,alsoconductsannualRAassessmentsoftheWesternInterconnectionthroughitsWesternAssessmentofResourceAdequacy.12

•TheNorthwestPowerandConservationCouncil(NWPCC)developsalong-termrecommendedresourceprocurementstrategy(thePowerPlan)forthePacificNorthwest(Idaho,Montana,

Oregon,Washington)foraforthcomingfive-yearperiodanddevelopsitsannualPowerSupplyAdequacyAssessmenttoensurethePowerPlan’sresourcestrategywillmeetRAtargets.13

•BonnevillePowerAdministration,oneofthetwopowermarketingadministrationsinthe

Westthatsellpowerproducedbyfederaldamstoutilities,14,iialsodevelopsitsownresource

acquisitionstrategy,consistentwiththeNWPCC’sPowerPlanbutbasedonitsownRAcriteria.Italsoproducesanannuallong-termregionalloadandresourceforecastcoveringthenext

10years.15

•InCalifornia,threeentities—theCaliforniaIndependentSystemOperator(CAISO),theCaliforniaPublicUtilitiesCommission(CPUC),andtheCaliforniaEnergyCommission—eachhave

complementaryrolesinevaluatingRAandprocurementinthestate.16

•TheWesternPowerPool,amember-basedorganizationcomprisedofelectricutilitiesand

othermemberentitiesacrosstheWest,recentlydevelopedtheWesternResourceAdequacy

Program(WRAP),aforward-lookingcapacity-sharingprogramthatenablesparticipatingutilitiestoaccesspooledcapacityresourcesneededduringunplannedoutageperiods.17TheWRAP

frameworkdevelopsastandardizedaccountingmethodologyfortheregionalresourcesofitsparticipatingmemberswithfuturebindingconditionsformembers,iiiallowingformorereliableresourcesharingandRAassessmentwithinitsfootprint.RegularRAassessmentswillbeusedtoinformprogramcomplianceamongmemberutilities.

StateregulatorsplayauniqueroleinevaluatingandensuringRA.Althoughmanyutilitiesandregionalentitiesproducelong-termRAassessments,regulatorshavetheauthoritytoultimatelyensurethatutilitiesbuildareliablesystemthatisresourceadequate,atlowestcostfor

customers,andinlinewithadditionalstatepolicies.Todoso,regulatorsneedtohaveathoroughunderstandingoftheRAriskstheirutilitiesfaceandanunderstandingofthesuiteofoptionsthatcanbeimplementedtomitigatepotentialriskswhilemaximizingbenefitsforcustomers.

iiTheWesternAreaPowerAdministrationistheotherpowermarketauthorityintheWest.ItdoesnotconductitsownRA

assessmentbutrequiresitscustomerentitiestodotheirownRAevaluations.

iiiUtilitiesrecentlydelayedthefirstbindingseasonoftheWRAPbyoneyear,tonowbeginin2027.

PoweringThroughUncertainty:AResourceAdequacyToolkitforWesternRegulators

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ThefirstpartofthisreportaimstohelpWesternregulatorsunderstandtheuniquechallengesthatare

creatinguncertaintyaroundmaintainingRAontheWesterngrid.Thesecondpartprovidesthreepracticalstrategiesregulatorscanpursuetocost-effectivelyimproveRAoutcomesduringthetransitiontoa

low-carbonWesterngrid,withexamplesofwheretheseactionshavealreadybeenimplemented.Thesestrategiesare:(1)improveplanningprocessestoreflectmoderndriversofrisk,(2)broadenthesetof

technologiesthatcansupportRAintheshortandlongterm,and(3)pursueutilitybusinessmodelreformsthatcansupportRA(seeExhibit3).Weofferarangeofoptionstosupporteachstrategy,recognizingthatthediversityofregionalresourcemixes,regulatorystatutes,andstatepoliciesthroughouttheWestmeanthattherewillbenoone-size-fits-allapproach.

Exhibit3Regulatorystrategiesthatcanreduceresourceadequacyuncertaintywhilesupportinganafordabletransitiontoalow-carbongrid

Improveplanningpracticestoreflectmoderndriversofrisk

Broadenthesetoftechnologiesthatcansupportresourceadequacyintheshortandlongterm

Pursueutilitybusinessmodelreforms

thatcansupportresourceadequacy

RMIGraphic.

PoweringThroughUncertainty:AResourceAdequacyToolkitforWesternRegulators

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DriversofResourceAdequacyUncertainty

Numerousstudiesandevaluationshaveconcludedthatinthenearterm,existingresourcesandplannedbuildsarelikelytomaintainaresource-adequategridfortheWestunderstandardconditions.18Inits2023assessmentofRA,WECCstatedthatinthenearterm(2024–25),thereare“veryfewdemand-at-riskhourswithnominalamountsofdemandatrisk.”19Meanwhile,theNWPCCfoundthatunderstandardexpectedconditions,itsmostrecent(2021)PowerPlan’sresourcestrategyeliminatesnearlyallsummershortfallswhilelimitingwinterriskperiodstoonlyafewhours.20

However,severalnewdimensionsofuncertaintyareincreasingtheriskofinadequatepowersupplyinthe

Westinthecomingyears,evenleadingsomeWesternutilitiestodelayfullbindingparticipationintheWRAPasaresult.21Theriskfactorscommonlyidentifiedacrossstudies,includinginWECC’smostrecentassessmentofRA,includeloadgrowth,extremeweatherandclimatechange,delaysinplannedresourcebuilds,andslowtransmissionexpansion(seeExhibit4).Detailsoneachoftheseriskfactorsaredescribedbelow.

Exhibit4DriversofresourceadequacyuncertaintyintheWest

Transmissionconstraintsthatisolate

utilitysystemsandlimitthegrowth

ofnewgenerationresources

Uncertaintiesaroundthescale,

timing,andtypeofloadgrowth

fromresidential,commercial,

andindustrialelectrification

Extreme

weat