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Distributed Energy Resources in Local Integrated Energy Systems: Optimal Operation and Planning Giorgio Graditi

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Energy Storage Systems: System Design and Storage Technologies Armin U. Schmiegel

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Editedby GiorgioGraditiandMarialauraDiSomma

TheEditors

Dr.GiorgioGraditi

ItalianNationalAgencyforNew Technologies

EnergyandSustainableEconomic Development

ENEA,DepartmentofEnergy TechnologiesandRenewableSources

Rome,Italy

Dr.MarialauraDiSomma

ItalianNationalAgencyforNew Technologies EnergyandSustainableEconomic Development

ENEA,DepartmentofEnergy TechnologiesandRenewableSources Rome,Italy

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Contents

1ChallengesandOpportunitiesoftheEnergyTransitionand theAddedValueofEnergySystemsIntegration 1

MarialauraDiSommaandGiorgioGraditi

1.1EnergyTransformationTowardDecarbonizationandtheAddedValueof EnergySystemsIntegration 1

1.2EuropeanUnionastheGlobalLeaderinEnergyTransition 6

1.3PillarsfortheTransitionTowardIntegratedDecentralizedEnergy Systems 11

ListofAbbreviations 13 References 13

2IntegratedEnergySystems:TheEngineforEnergy Transition 15

MarialauraDiSommaandGiorgioGraditi

2.1Introduction:theConceptofIntegratedEnergySystem 15

2.2KeyEnablersforIntegratedEnergySystems 18

2.2.1StorageandConversionTechnologies 18

2.2.2EndUserEngagementandEmpowerment 22

2.2.3DigitalizationEnabler 24

2.2.4EmergenceofanIntegratedEnergyMarket 27

2.3IntegratedEnergySystemsattheLocalLevel 28

2.3.1ConceptualizingLocalIntegratedEnergySystems 28

2.3.2MapofEnablingTechnologies 29

2.3.3KeyStakeholdersandRelatedBenefitsfromLocalIntegratedEnergy SystemsDeployment 31

2.4MainBarriersforImplementation 33

2.4.1Techno-economicBarriers 34

2.4.2SocioeconomicBarriers 35

2.4.3PolicyandRegulatoryBarriers 35

2.5Conclusions 36

ListofAbbreviations 38 References 38

3PowerConversionTechnologies:TheAdventofPower-to-Gas, Power-to-Liquid,andPower-to-Heat 41

JoshuaA.Schaidle,R.GaryGrim,LingTao,MarkRuth,KevinHarrison, NancyDowe,ColinMcMillan,ShantiPless,andDouglasJ.Arent

3.1Introduction 41

3.1.1MotivationforPower-to-X 41

3.1.2DefiningPower-to-XCategories 43

3.1.3GoalofthisChapter 44

3.2Power-to-XTechnologies 44

3.2.1Power-to-Gas 44

3.2.1.1NaturalGasMarketDemand 45

3.2.1.2TechnologyIdentificationandOverview 46

3.2.1.3UniqueIntegrationChallengesandOpportunities 47

3.2.2Power-to-Chemicals-and-Fuels 48

3.2.2.1MarketandDemand 48

3.2.2.2TechnologyIdentificationandOverview 49

3.2.2.3UniqueIntegrationChallengesandOpportunities 54

3.2.2.4ImplicationsonPowerGeneration 54

3.2.3Power-to-Heat 57

3.2.3.1MarketandDemand 57

3.2.3.2TechnologyIdentificationandOverview 60

3.2.3.3UniqueIntegrationChallengesandOpportunities 60

3.2.3.4ImplicationsonPowerGeneration 62

3.3OverarchingChallenges,Opportunities,andConsiderations 62

3.3.1FeedstockandEnergySourcing 62

3.3.1.1Feedstocks(CO2 ,N2 ,H2 O,andBiomass) 62

3.3.1.2OperationalFlexibilityforGridIntegrationandRevenue 63

3.3.2KeyConsiderationsfromLifeCycleAnalysisandTechno-economic Analysis 64

3.3.2.1LifeCycleAnalysis 64

3.3.2.2Techno-EconomicAnalysis 64

3.3.3BusinessModelandBusinessInnovation 65

3.4ConcludingRemarks 66 Disclaimer 66

ListofAbbreviations 66 References 67

4RoleofHydrogeninLow-CarbonEnergyFuture 71

AndreaMonfortiFerrario,VivianaCigolotti,AnaMarìaRuz,FelipeGallardo, JoseGarcía,andGiuliaMonteleone

4.1Introduction 71

4.2MainDriversforHydrogenImplementation 72

4.2.1IncreasingPenetrationofStochasticRenewableEnergy 73

4.2.2OpportunityofHydrogenasaSectorCouplingEnabler 74

4.3HydrogenEconomyandPolicyinEuropeandWorldwide 74

4.4MainRenewableHydrogenProduction,Storage,and Transmission/DistributionSchemes 77

4.4.1HydrogenProductionPathways 77

4.4.2HydrogenTransmissionandDistribution 79

4.4.2.1MainHydrogenStorageTechnologies 79

4.4.2.2MethodsforHydrogenTransmissionandDistribution 81

4.5TechnologicalApplicationsinIntegratedEnergySystemsand Networks 83

4.5.1HydrogenasanEnergyStorageSystemforFlexibilityatDifferent Scales 83

4.5.2IndustrialUseasaRenewableFeedstockinHard-to-AbateSectorsand fortheProductionofDerivates 84

4.5.3HydrogenMobility:AComplementarySolutiontoBatteryElectric Vehicles 85

4.5.4FuelCells,FlexibleElectrochemicalConversionSystemsfor High-EfficiencyPower,and/orCHPApplications 86

4.6Conclusions 89

ListofAbbreviations 90 References 91

5ReviewontheEnergyStorageTechnologieswiththeFocuson Multi-EnergySystems 105 MortezaVahid-Ghavidel,SaraJavadi,MatthewGough,MohammadS.Javadi, SérgioF.Santos,MiadrezaShaﬁe-khah,andJoãoP.S.Catalão

5.1Introduction 105

5.2EnergyStorage 106

5.2.1MainConceptofEnergyStorageinthePowerSystem 106

5.2.2DifferentTypesofEnergyStorageSystems 108

5.2.2.1ElectromechanicalEnergyStorageSystems 110

5.2.2.2ElectromagneticEnergyStorageSystems 111

5.2.2.3ElectrochemicalEnergyStorageSystems 112

5.2.2.4ThermalEnergyStorageSystems 113

5.2.3AdvantagesofStorageintheEnergySystem 113

5.3EnergyStorageTechnologyApplicationintheMulti-Energy Systems 116

5.4Conclusion 118

ListofAbbreviations 119 References 119

6DigitalizationandSmartEnergyDevices 123 MaherChebbo

6.1Introduction 123

6.2OurVisionoftheDigitalNetworks 130

6.3EnablingState-of-the-ArtDigitalTechnologies 138

6.4KeyDigitalUseCasesandAssociatedBenefits 144

6.5IntegratedDigitalPlatformAcrossStakeholders 149

6.6KeyDigitalRecommendations 150

6.7Conclusion 156

ListofAbbreviations 159 References 160 FurtherReading 162

7SmartandSustainableMobilityAdaptationTowardtheEnergy Transition 165

CarlaSilva,CatarinaMarques,MarianaRaposo,andAngeloSoares

7.1SmartandSustainableMobilityDefinitionsandMetrics 165

7.1.1SustainableMobilityKPI(KeyPerformanceIndicators) 167

7.1.2KPIofUrbanMobilityinTwoEuropeanCities 169

7.2SmartMobilityAppliedtoBicycleSharinginUrbanContextandImpacts onSustainability 175

7.3Ground-LevelOzoneIndicator 178

7.4EnergyTransition 179

7.5ResilienceoftheMobilitySystem 180

7.6Conclusions 182 Acknowledgments 182

ListofAbbreviations 183 References 184

8EvolutionofElectricalDistributionGridsTowardtheSmart GridConcept 187

LucíaSuárez-Ramón,PabloArboleya,JoséLorenzo-Álvarez,and JoséM.Carou-Álvarez

8.1SmartGridConcept 187

8.2AdvancedMeteringInfrastructure(AMI)GeneralDescription 188

8.3CommunicationsandImpactonRemoteManagement 199

8.3.1PLCPRIMECommunication 200

8.3.2DataConcentratorUnit(DCU)Description 204

8.3.3SmartMeterDescription 205

8.3.4FutureScenario:EvolutionofCommunicationsTowardHybrid Systems 206

8.4CentralSystemforDataReceptionandAnalysis 206

8.4.1Real-TimeEventManagement 207

8.4.2LVNetworkMonitoring 208

8.4.3AutomaticDiagnostic 208

8.5DSOChallenge:AMIforLVNetworkManagement 209

8.6DigitalTwinoftheLVNetwork 210

8.7EvolutionoftheFunctionalitiesforLVNetworkManagement 212

8.8Conclusions 213

ListofAbbreviations 213 References 214

9SmartGridsfortheEfﬁcientManagementofDistributed EnergyResources 215

RobertoCiavarella,MarialauraDiSomma,GiorgioGraditi,andMariaValenti

9.1ElectricalSystemTowardtheSmartGridConcept 215

9.1.1TechnologyAreasofSmartGrids 218

9.1.2ServicesandFunctionalitiesoftheSmartGrids 219

9.1.2.1NeedstoIntegrateNewEmergingTechnologies 220

9.1.2.2ImprovetheOperationoftheNetwork 220

9.1.2.3NewInvestmentPlanningCriteria 220

9.1.2.4ImprovetheFunctionalityoftheMarketandServicestoEndUsers 220

9.1.2.5ActiveInvolvementoftheEndUser 221

9.1.2.6IncreasedEnergyEfficiencyandReducedEnvironmentalImpact 221

9.2NeedofaMulti-DomainOptimizationinSmartGrids 221

9.3AdvancedControlMechanismsforSmartGrid 225

9.3.1ArchitectureandGridModel 225

9.3.2CongestionIssuesintheTSODomain 226

9.3.3CongestionIssuesintheDSODomain 228

9.3.4FrequencyInstabilityintheTSODomain 230

9.4CaseStudies 231

9.4.1CaseStudy1:CongestionEventsattheTransmissionLevel 231

9.4.2CaseStudy2:CongestionEventsattheDistributionLevel 232

9.4.3CaseStudy3:FrequencyInstabilityIssues 233

9.5Conclusions 234

ListofAbbreviations 235 References 235

10NearlyZero-EnergyandPositive-EnergyBuildings:Statusand Trends 239

DeniaKolokotsa,GloriaPignatta,andGiuliaUlpiani

10.1Introduction 239

10.1.1ConceptofNearlyZero-andPositive-EnergyBuildings 240

10.1.1.1Definitions,Regulations,andStandards 240

10.1.2OverviewofDesignStrategies 242

10.1.2.1EnergyConservationStrategies 243

10.1.2.2EnergyGenerationStrategies 246

10.1.2.3SmartReadiness 248

10.2StatusandResearchDirectionsonHigh-PerformanceBuildingsfor theComingDecade 253

10.2.1OverviewofCaseStudiesandResearchProjects 253

10.2.1.1Challenges,Drivers,andBestPractices 256

x Contents

10.2.2TransitionfromIndividualNearlyZero-EnergyBuildingsto Positive-EnergyDistricts(PEDs) 258

10.3Conclusions 259

ListofAbbreviations 260 References 261

11TransitionPotentialofLocalEnergyCommunities 275 GabrieleComodi,GianlucaSpinaci,MarialauraDiSomma,and GiorgioGraditi

11.1Introduction 275

11.1.1“2030AgendaforSustainableDevelopment”ofUnitedNations 276

11.1.2CleanEnergyforAllEuropeanPackage:RenewableandCitizen“Energy Communities” 277

11.1.3HumanCapitalforLocalEnergyCommunities 278

11.1.4LocalEnergyCommunities:AnOrganizationalBottom-UpModelto EmpowerFinalUsers 279

11.2LocalEnergyCommunitiesMakingtheGreenDealGoingLocal 280

11.2.1GameChangeroftheGreenDeal 280

11.2.2GreenDealGoingLocal 283

11.2.3NeighborhoodApproachandLocalEnergyCommunitiesintheGreen Deal 284

11.3LocalEnergyCommunitiesasIntegratedEnergySystemsatLocal Level 285

11.3.1LocalEnergyCommunitiesasPromotersforSectorCoupling 285

11.3.2OptimalMedium–Long-TermPlanningforLocalEnergy Communities 287

11.3.3KeyTechnologiesintheContextofLocalEnergyCommunities 288

11.3.4DigitalizationtoEnableFlexibilityandEmpowerFinalUsers 296

11.4LocalEnergyCommunitiesandEnergyTransition:AVisionfortheNext Future 298

11.4.1SomeReflections 299

11.5Conclusions 300

ListofAbbreviations 301 References 302

Index 305

ChallengesandOpportunitiesoftheEnergyTransitionand theAddedValueofEnergySystemsIntegration

MarialauraDiSommaandGiorgioGraditi

ItalianNationalAgencyforNewTechnologies,EnergyandSustainableEconomicDevelopment,ENEA, DepartmentofEnergyTechnologiesandRenewableSources,Rome,Italy

1.1EnergyTransformationTowardDecarbonizationand theAddedValueofEnergySystemsIntegration

Theglobalenergytransformationisalreadyinplace,andthisrepresentsthemain replyofhumanitytosafeguardglobalclimateandmaintainsustainableexistenceon Earth.Thefirststeptowardthisenergytransformationandtheinternationalcommitmenttocombatingclimatechange,increasingenergyaccess,andmaintaining biodiversityisrepresentedbytheParisAgreementsigningatCOP21withthegoal tomaintainglobalwarminglowerthan2 ∘ Cabovethepre-industriallevels.ConcurrenttotheParisAgreement,countriescommittedtotheUnitedNations(UN) 17SustainableDevelopmentGoals(SDGs),representingtheplantowardabetter worldforpeopleandourplanettobeachievedby2030[1].Tacklingclimatechange isatransversalgoalforalmostallSDGs.Althoughtheinternationalcommitmentis evident,challengesstillremainforthesuccessfulimplementationoftheParisAgreementandclimate-andenergy-relatedSDGs,andthegapbetweenaspirationand realityincombatingclimatechangeremainssignificant.

Meetingtheseambitiousgoalsrequiresthecommitmentbeyondtheelectricity sector,whereasprovidingdecarbonizationacrossdifferentsectorsthroughanintegratedapproachcanrepresentavalidsolution.ThisisthemainideabehindtheconceptofIntegratedEnergySystemsthat,accordingtotheETIPSNETVision2050[2], aredefinedasanintegratedinfrastructureforallenergycarriers,withtheelectrical systemasthebackbone.Thesesystemsarecharacterizedbyahighlevelofintegrationamongallnetworksofenergycarriersobtainedthroughcouplingelectrical andgasnetworks,heating,andcooling,supportedbyenergystorageandconversion processes.Couplingdifferentsectorsindicatesincreasingeffortsinasynergicway bycoordinatingtheplanningandtheoperationofenergysystemsacrossmultiple energycarrierswhilealsoachievingamoreflexible,reliable,andefficientenergy systemasawhole.

Themainenergytrendstowarddecarbonizationarediscussedbelowalongwith theaddedvalueofferedbyenergysystemsintegration.

Evolutionofthecurrentenergysystemtoanelectriﬁedenergysystem.

Electrification isconsideredavalidcost-effectivepathwayfordecarbonization offinalenergyconsumption.Thisismainlyduetothefactthatseveraltechnologies forconvertingrenewableenergyintoelectricityhaverecentlybecomeavailableat competitivepricessuchasPVandwindturbines.Ontheotherhand,alargepartof CO2 emissionsinindustries,transport,andbuildingsisnotrelatedtopowersector buttoenduseoffossilfuels.Thatiswhy,alarge-scaleelectrification,characterized bythepenetrationofanelectricitycarrierproducedbyrenewabletechnologiesin building,transport,andindustrysectors,representsagoodpathwayfordecarbonization.AccordingtotheInternationalRenewableEnergyAgency(IRENA)Renewable EnergyRoadmap(REmap)[3],theshareofelectricityinfinalenergyconsumption amountsto20%todayandwillreachthepercentagesof29%,38%,and49%in2030, 2040,and2050,respectively.

Figure1.1showsthechangefromthecurrentenergysupplysystemwherethe electricitydemandistypicallysatisfiedbyanelectricitynetworkandheatdemand bygas-firedboilerssuppliedbyagasnetworktoanelectrifiedenergysystem,where theelectricitynetworkisusedtosatisfyallenergydemands,includingheatdemand throughPower-to-Heat(PtH)technologies.Anelectrifiedfutureposesimportant questionssuchashowmuchadditionalpowernetworkcapacitydoweneedtosatisfyalltypesofenergydemands?Or,whathappensifthereisacontingencyinthe powersystem?

Astrongelectrificationscenariocreatesanumberofchallengesfortheoperation ofapowersystem,whichinprinciplewouldneedadditionalflexibility,reinforcement,andnewinvestmentsforthetransmissionanddistributionnetworks.

InFigure1.2,thecurrentenergysystemiscomparedtoanintegratedenergysystem,whichissomethingmorethananelectrifiedenergysystem.Infact,insuch system,multiplehybridenergytechnologiesaremanagedwithhighsynergytosatisfythemulti-energydemandandservicescanbeprovidedwiththemostconvenient energycarrierandsector.

Ifelectrificationoffinalconsumptioniscombinedwiththeintegrationofenergy sectors,decarbonizationofenergydemandwouldbereachedthroughpenetration ofrenewablesinallenergyendusesectorswhilealsogettinghigherflexibility forthewholesystembyreducingtheneedsforreinforcingtheexistingnetwork infrastructures.Moreover,energysystemsintegrationallowsincreasingefficiency intheenergyresourcesusethroughexploitingsynergiescomingfromtheinterplay

Figure1.1

Figure1.2 Comparisonbetweenthecurrentenergysystemandanintegratedenergy system.

ofdifferentenergycarriersandreductionofrenewableenergysource(RES) curtailment.Inpractice,forinstance,inthecaseofexcesselectricityfromRES,it canbeconvertedintogasashydrogenorsyntheticmethanethroughPower-to-Gas (PtG)technologies,storedand/ortransportedbyexistinggasinfrastructuresfor immediateorlaterusage,orre-convertedagainintoelectricitywhenrenewable electricitysupplyisinsufficienttosatisfytheloads.Ontheotherhand,PtH technologiescombinedwiththermalstoragecanshiftproductionofthermalenergy whenrenewableelectricityisinexcess,therebyrepresentinganotheroptionfor reducingREScurtailment[4].

Also,inthetransportsector,electrificationcanbeasuccessfulstrategyfor decarbonization,whilemakingthesystemasawholemoreflexible.Infact,electric vehiclesinPower-to-Mobility(PtM)applicationrepresentavalidalternativeto traditionalcarswithinternalcombustionenginesandcanprovideflexibilityto theelectricitysystemthroughsmartchargingstrategies,forinstance,bycharging batteriesduringtheperiodoflowdemands,therebyflatteningouttheelectricity loadprofile.

Similarly,heatpumpsinPtHapplicationrepresentacost-effectiveandmoreefficientalternativetoconventionalgas-firedboilersforheatingpurposesinbuildings andalsoforreducingprimaryenergyconsumptionthankstotheirhighconversion efficiency.

AccordingtoREmap[3],thenumberofelectricvehiclesworldwidewillpassfrom thecurrent6millionsto157,745,and1166millionsin2030,2040,and2050,respectively,whereasthenumberofheatpumpinstallationswillpassfromthecurrent 20millionsto155,259,and334millionin2030,2040,and2050,respectively.The strongexpectedelectrificationoftransportationandheatingsectorscouldleadto higherpeakloads,therebyrequiringhigherflexibilitytomatchelectricitydemand andsupply.Again,alsointheselattercases,theaddedvalueofenergysystemsintegrationisgivenbythepossibilitytostoreexcesselectricityfromRESandprovide back-upsupplytocoverpeakloads,therebyensuringbalanceatalltimeswithclean energyintheequation.

Anothermajortrendinenergylandscapeisrepresentedbythe large-scale deploymentofdistributedgeneration(DG). Inthepastyears,thepower systemhasbeenaffectedbyafundamentalrevolutionascomparedtoitstraditional

1ChallengesandOpportunitiesoftheEnergyTransition

conception.Thedeploymentofrenewabletechnologiesatalocallevelledtothe switchfroma“one-way”generationsystemmainlyrelyingonafewlargepower plantsconnectedtoHVandEHVgridsandlocatedfarfromconsumptionareas toa“multi-directional”system,whosecharacterizationandmanagementare extremelycomplex.Inthetraditionalelectricitysystem,theelectricityproducedin largepowerplantsreachestheusers–throughthetransmissionanddistribution networks–playingthepassiveroleofenergyconsumers.Ontheotherhand,the energymodelofDGmainlyconsistsofanumberofmedium–smallgeneration units(fromafewtens/hundredsofkilowattstoafewmegawatts)usuallyconnected todistributionnetworks.DGunitsareusuallylocatedclosetotheloadstosatisfy anddesignedtoexploitrenewablesourcesspreadthroughouttheterritoryand otherwisenotusablethroughtraditionallarge-sizegenerationunits.

Thebenefitsofferedbythisnewenergymodelaredifferent:

● increaseoftheefficiencyoftheelectricitysystemthankstothereductionofenergy transportloss;

● increaseofRESpenetrationlevelsandmorerationaluseofenergy;and

● optimizationoftheresourcesatlocallevelandthelocalproductionchain.

AccordingtoREmap[3],therenewableenergyshareinpowergenerationwill morethandoublein2030,reachingthevalueof57%ascomparedtothecurrent percentageof25%,toarriveatvaluesof75%and86%in2040and2050,respectively. OnlyinthecaseofPVsystems,theREmapcasesforeseethattheannualsolarPV additionswillpassfromthecurrentvalueof109GW/yrto360GW/yrin2050,and asimilarsituationisexpectedforwindsource,forwhichtheannualadditionsare expectedtopassfromthecurrentvalueof109GW/yrto240GW/yrin2050.

Theincreasingintermittentrenewablespenetrationinelectricitysystemsisleadingtoanincreaseinthereliabilityandstabilityproblems.Themitigationofuncertainty,whichimperilsthebalancebetweengenerationanddemand,urgesthesearch ofnewsourcesofancillaryservices,traditionallyprovidedbybulkysynchronous generators.Energysystemsintegrationandinparticularthecouplingoftheelectricityandgassectorsrevealspromisingflexibilitysolutionsforpowersystemsthrough energyconversionandhydrogenstorage.Ontheotherhand,theoperationofPtG technologiesinperiodsofexcesselectricitysupplyremovestheneedforcurtailment ofrenewableelectricitygenerationortheneedforadditionalinvestmentsinelectricitytransmission,distribution,orstorageinfrastructure.

Animportantaspectcloselyrelatedtothechangesthatareaffectingtheenergy sectoristhe evolutionoftheroleoftheenergyconsumer.Historically,thecitizenhasbeena“passive”user,coveringtheroleofthecustomerusingtheenergyproducedatacentralizedleveltomeettheenergyneeds.Conversely,thescenariothat hasbeentakingshapeinrecentyearsseestheemergenceofanewtypeof“active” customerwho,thankstodigitization,ismoreinformedabouttheownconsumptionandenergypricesandismoresensitivetotheuseof“green”energyresources. ThroughDGunits,theendusershavetheabilitytoproduceandconsumetheir ownenergytostoreitandsellitbacktothegridbyexploitingtheRESavailable locally;therefore,fromsimpleconsumers,theybecome“prosumers.”Thedirect

consequenceisthebirthofthe“self-consumption”concept,wheretheconsumption ofenergyproducedoccursinthesamesitewhereitisconsumed,bothinstantaneouslyandthroughstoragesystems,regardlessofthesubjectscoveringtherole ofaproducerandafinalcustomer,providedthattheyoperateinthesamesuitablydefinedandconfinedsiteandregardlessofthesourcethatfeedsthegenerationunit.

AnotherelementthroughwhichtheenduserassumestheactiveroleinthechangingenergylandscapeisrepresentedbyDemandResponse(DR).TheUnitedStates DepartmentofEnergy(DoE)definesDRprogramsaschangesinelectricityconsumptionbyendusersinresponsetochangesinthepriceofenergyovertimeorthe paymentofincentivesdesignedtoleadtolowerconsumptionofelectricityinperiodswhenthewholesalemarketpriceishighorwhensystemreliabilityproblems occur[5].

Accordingtotheaforementioneddefinition,theDRisanactiveresponsefrom consumersbasedonthepriceofenergyoronthepaymentofincentives.InDRprograms,theconsumersareinducedtoquicklychangetheirelectricityconsumption whenthereisahighenergydemandortherearelow-reservemargins.Thereduction/modulationofenergyconsumptionaccordingtomarketpricetrendshelpsto limittheoccurrenceofenergypricepeaks.Atthesametime,DRservicesrepresent animportanttoolfornetworkoperatorsinmaintainingabalancebetweensupply anddemandandinensuringthereliabilityofthesystem.Theendusercan,therefore,temporarilyvarythepowercommitmentinresponsetoapricesignal(deriving fromtariffsordirectlyfromtheelectricitymarket)orincompliancewithagreements madewithsubjectssuchasaggregatorsandnetworkoperators.

ItisimportanttounderlinethatlocalDGunitscanalsobeconsideredasaDR resourceastheyalsoallowforareductioninthewithdrawalofenergyfromthegrid withoutaffectingtheabsorptionandloadcurvesofconsumers.Theclassicactions thatDRcanadoptcanbedividedintothreemaincategories:

● reductionofdemandinthepeakperiodsofthesystem;

● shiftingofdemandfrompeakperiodstooff-peakperiods,obtaininganeffectof levelingthepeaksandfillingthevalleysoftheloadcurve(loadshifting);

● self-productionoruseofenergystored,whichdoesnotchangetheinternalabsorptionprofileoftheuser’ssystembutallowstoreducetheenergydemandfromthe network.

Lastbutnotleast,theemergingparadigmofenergycommunitiesisexpectedto functionasanimportanttoolforengagingendusersinrenewablegenerationand lowcarbontechnologies,whilealsopromotingparticipationinthemarketofend usersthatotherwisecouldnotbeabletodoso.

Theaddedvalueofenergysystemsintegrationinthemajortrendrelatedtoend userengagementandempowermentismainlygivenbythepossibilitytoexploitsynergiesamongmultipleenergycarriersatthelocalleveltoincreaseenergyefficiency andRESutilization,aswellastoenhancethepotentialofdecarbonizationofthe energydemandforheatingandcooling.Forinstance,PtHimplementedthrough heatpumpsallowstoachievelargerflexibilityoftheenergydemandandimprove

1ChallengesandOpportunitiesoftheEnergyTransition

considerablytheuseofrenewablesforheatingandcoolingdemandsinbuildings. Moreover,thehighconversionefficiencyofthistechnologycanleadtoimportant economicandenvironmentalbenefits.ThePtHtechnologycoupledwiththermal storagecouldbeevenmoreconvenient,thankstothepossibilitytoactivateDRservicesandofferancillaryservicestotheelectricgrid.Infact,theexcessrenewable electricalenergyproducedcouldbeconvertedintothermalenergyandstoredin thermalenergystorage,therebyreducingREScurtailmentandmakingtheelectricalgridmorestabletosuddenvariationsofRES.Thisbringsbenefitsalsotonetworkoperatorsthroughamoreefficientuseoftheexistinggenerationcapacity,the reducedneedtoupgradethedistributionnetwork,thereductionofpeakloads,and themoreflattenedloadforms,aswellasthereductionofmanagementcostsofgenerationunits.Inadditiontoefficientelectricity-based(viaheatpumps)heatingand coolingdevicesinsinglehousesandsmallresidentialbuildings,low-carbondistrictheatingandcoolinggridscancoverthegenerationanddistributionofthermal energyinurbandistricts.Ontheotherhand,couplingelectricityandheatingsectorsthroughcombinedheatandpower(CHP)systemswouldallowtoexploitlocally thewasteheatfrompowergenerationprocessesforthermalpurposesinbuildings, therebyincreasingtheefficiencyinenergyresourceuse.

1.2EuropeanUnionastheGlobalLeaderinEnergy

Transition

ThetransitionofEuropeanUnion(EU)tonet-zerocarbonemissionsby2050is abigchallengebutalsoagreatopportunitytomodernizethecontinent’seconomyandpromotegrowth,employment,technologicaladvancement,andsocial inclusion.

AneffectivedemonstrationoftheEUcommitmentincombatingclimatechange isrepresentedbythe CleanenergyforallEuropeanspackage [6],whichisa fundamentalmeasuretolaythefoundationsfortherealizationof“aneutralclimateeconomy”by2050.Itcontainsasetofmeasuresrelatedtoenergyefficiency, renewableenergy,structureoftheelectricitymarket,securityofelectricitysupply, andgovernancerulesfortheEnergyUnion.Itconsistsofeightlegislativeactsthat provideforanupdateoftheEuropeanenergypolicyframeworkaimedatfacilitatingtheenergytransition,definingamodernEuropeanenergymarket,promoting andintegratingelectricityproducedfromRES,promotingenergyefficiency,and strengthentheregulatoryframeworkinwhichEuropeanandnationalinstitutions operate.

Inmoredetails,theCleanEnergyPackageintroducessignificantchangestothe structureoftheEuropeanelectricitymarketbyrevisingandreplacingtheprovisions containedinRegulation2009/714/EC[7]andinDirective2009/72/EC[8],currently atthebasisoftheregulatoryframeworkrelatingtotheinternalelectricitymarket oftheUnion.Thesechangesactuallyallowforthecreationofanelectricitymarket fortheUnioncharacterizedbymorevariableanddecentralizedproduction,greater interdependencebetweenindividualnationalmarkets,andhigheropportunities

1.2EuropeanUnionastheGlobalLeaderinEnergyTransition 7 forconsumerstoparticipateasactiveplayersinthemarketthroughdemandside management,aggregation,self-generation,andtheuseofstoragesystemsand digitalization.Thenewdirective2019/944/EU(EnergyMarketDirective–EMDII) [9]aimstoadaptthecurrentregulatoryframeworktothenewmarketdynamics takingintoaccounttheopportunitiesandchallengesrelatedtothedecarbonization objectiveoftheenergysystemandthepossibletechnologicaldevelopments,in particularthoserelatingtoconsumerparticipationandcross-bordercooperation. ThemainobjectiveofEMDIIistheconstructionofaninternalmarketgoverned bycommonrulesthatcanguaranteeeveryoneaccesstotheelectricitycarrier.In relationtoconsumers,theEMDIIprovidesanimportantparadigmshift,aimed atqualifyingconsumersas“activeconsumers,”whocanoperatedirectlyorin aggregatedmanner,sellself-producedelectricity,aswellasparticipateinflexibility andenergyefficiencymechanisms.Thedirectivestatesthatallconsumersshould beabletobenefitfromdirectparticipationinthemarket,inparticularbyadjusting consumptionaccordingtomarketsignalsand,inreturn,bybenefitingfromlower electricitypricesorotherincentives.Anotherimportantinnovationenvisagedby theEMDIIdirectiveconcernstheintroductionofthenotionof CitizenEnergy Community oranenergycommunitywhichwillbeguaranteedtooperateonthe marketunderequalandnon-discriminatoryconditionscomparedtoothermarket players,beingabletofreelycovertherolesofendcustomer,producer,supplier,or managerofdistributionsystems.

TheinnovationsintroducedbytheCleanEnergyPackageinthefieldofenergy producedfromrenewablesourcesareaimedatencouragingtheuseofthese resourcesfortheenergytransitionupto2030,settingnewobjectivesattheEU level,simplifyingtherelatedauthorizationprocedures,providingstabilityto thefinancialsupportsandstrengtheningconsumerrights.ThenewDirective 2018/2001/EU(RenewableEnergyDirective REDII)[10]onthepromotion oftheuseofenergyfromrenewablesourcesappliesasubstantialrevisionofthe regulatoryframeworkprovidedforinDirective2009/28/EC[11].Indetail,REDII paysparticularattentiontotheself-consumptionofrenewableenergy,providing thatconsumersareallowedtobecomeconsumersofrenewableenergy,capable, also,ofproducing,storing,andsellingtheelectricitygeneratedinexcess,both individuallyandinaggregatedform.Anotherfundamentalinnovationenvisaged byREDIIistheintroductionofthenotionof RenewableEnergyCommunity,thatis anenergycommunitywiththerighttoproduce,consume,store,andsellrenewable energy.Furthermore,thesecommunitieswillbeabletoexchange,withinthesame community,therenewableenergytheyproduceandaccesstheelectricitymarket, directlyorthroughaggregation,inanon-discriminatoryway.

Theprovisionsonenergyefficiency,introducedbytheCleanEnergyPackage, aimtoestablishnewefficiencytargetsforboththeEUandtheMemberStates, introducingnewguidelinesandexpandingconsumerrightsinthefieldofheating andcoolingmetering,forbillingandfordomestichotwaterproduction.The newEnergyEfficiencyDirective[12]amendsthepreviousDirective2012/27/EU [13],modifyingthecurrentprovisionsdirectlylinkedtotheachievementofthe 2030targetsandintroducingnewrulesaimedatextendingconsumerrightsand

1ChallengesandOpportunitiesoftheEnergyTransition

improvingaccesstosmartmetering.Afurtherelementofthepackage,inthefieldof energyefficiency,isDirective2018/844/EU(newEnergyPerformanceofBuildings Directive–EPBD)[14],whichenteredintoforceon9July2018,amendingDirective 2010/31/EUontheenergyperformanceofbuildings.ThenewEPBDcontainsprovisionsconcerningenergyefficiencyobjectivesforbuildings,energycertification, methodsofverification,monitoringandcontrolofenergyconsumption,andthe definitionofobligationsrelatedtotheinstallationofchargingpointsforelectric vehicles.Furthermore,itintroducesthedefinitionoftheSmartReadinessIndicator (SRI)andamethodologytocalculatethisindicatortoassesstheabilityofabuilding orapropertyunittoadaptitsfunctioningtotheneedsoftheoccupierandthe networkandtoimproveitsenergyefficiencyandoverallperformance.Theindicatorofreadinessofbuildingstosmartnesstakesintoaccountthecharacteristicsof higherenergysaving,comparativeanalysis,andflexibility,aswellasfeaturesand capabilitiesthatareimprovedthroughmoreinterconnectedandsmartdevices.

Finally,theEURegulation2018/1999onthegovernanceoftheEnergyUnion andClimateAction[15]aimstoencouragecooperationbetweenMemberStates toachievetheEUenergyobjectivesandtargets,inparticularbystrengtheningthe programmingandreportingobligationsofindividualMemberStatesinthefieldof energy,climate,andinrelationtotheimplementationofthemeasuresenvisagedby thenewstructureoftheEnergyUnion.Theregulationoutlinesthefivedimensions oftheEnergyUnion,namely,(i)decarbonization,(ii)energyefficiency,(iii)energy security,(iv)internalenergymarket,and(v)research,innovation,andcompetitiveness,anddefinestheobligationforeachMemberStatetosendtotheEuropean CommissionaNationalIntegratedEnergyandClimatePlan,coveringperiodsof 10years.Theplanmust,amongotherthings,contain

● anoverviewoftheprocedurefollowedfordefiningtheplanitself;

● adescriptionofthenationalobjectivesandcontributionsrelatingtothefive dimensionsoftheEnergyUnion;

● adescriptionofthepoliciesandmeasuresadoptedtoachievetheaforementioned objectives;

● adescriptionofthecurrentstateofthefivedimensionsoftheEnergyUnion;and

● anassessmentoftheimpactsofthepoliciesandmeasuresimplementedtoachieve theaforementionedobjectives.

Promotingsecure,reliable,competitive,locallyproducedandsustainableenergy isanincreasinglycentralissueontheagendaoftheEuropeanCouncil,which inDecember2019announcedtheEuropeanGreenDeal[16],aroadmapwhose purposeistomaketheEU“afairandprosperoussociety,withacompetitiveand resource-efficientmoderneconomy,inwhichtherearenonetgreenhousegas emissionsin2050andeconomicgrowthisdecoupledfromtheresourcesused.”

TheGreenDealisdividedintoaseriesofmacro-actionscontainingstrategiesfor allsectorsoftheeconomy,inparticulartransport,energy,agriculture,construction, andindustrialsectors,includingnewregulatoryprovisionsandinvestments,tobe implementedinthenextyearstill2050.

Thestrategyisdividedintoeightmainobjectives:

(1)MakingtheEUclimategoalsfor2030and2050moreambitious;

(2)Ensurethesupplyofclean,economical,andsafeenergy;

(3)Mobilizingindustryforacleanandcirculareconomy;

(4)Buildingandrenovatinginanenergy-andresource-efficientway;

(5)Acceleratethetransitiontosustainableandsmartmobility;

(6)“Fromproducertoconsumer”:designingafair,healthy,andrespectfulfoodsystemoftheenvironment;

(7)Preserveandrestoreecosystemsandbiodiversity;and (8)“Zeropollution”foranenvironmentfreeoftoxicsubstances.

ThefirstclimateactioninitiativesundertheGreenDealinclude

● aEuropeanclimatelawtoincorporatethegoalofclimateneutralityintoEUlaw to2050,whichinturnhasfourobjectives:(i)establishthelong-termdirectionfor achievementofthe2050climateneutralitygoal;(ii)createamonitoringsystemof progressandtakefurtheractionifnecessary;(iii)provideconditionsofpredictabilitytoinvestorsandothereconomicactors;and(iv)ensurethatthetransitionto climateneutralityisirreversible.

● aEuropeanclimateagreement,aimedatspreadingawarenessandpromoting action,inafirstmomentfocusedonfourareas(greenareas,greentransport, greenproperties,andgreenskills),whileitmaysubsequentlyinvolveotherareas ofaction,suchasconsumptionandsustainableproduction,soilquality,healthy foodandsustainablenutrition,andsoon.

● TheClimateTargetPlan2030,withwhichitisintendedtofurtherreducenetemission(settinganewreductiontarget,for2030,ofatleast55%comparedtolevels of1990)butalsostimulatethecreationofgreenjobsandencourageinternational partnerstobemoreambitiousincontainingglobalwarmingbylimitingtheglobal temperatureriseto1.5 ∘ C.

● AnewEUstrategyonclimateadaptation,withtheaimtomakeadaptation smarter,faster,andmoresystemicandtostepupinternationalactiononadapting toclimatechangesothatEuropebecomes,by2050,aclimateresilientsociety fullyadaptedtotheinevitableimpactsofclimaticchange.

TheEU“GreenDeal”andtherelatedEuropeannationalrequirementssetprecise targetsby2030including:

● decarbonizationofthebuildingstock,transport,industry,andenergysystems;

● involvementofconsumersandcitizencommunitiesinenergysystems;

● digitalizationasanenableroftheenvironmentaltransitionandparticipative energymarkets;

● ambitiousreductionsintransportemissions;and

● reliability,adaptability,andresilienceoftheintegratedenergysystems.

TheenergytransitiontakingplaceinEUisalsodemonstratedbynumbers.The EUenergymix,overthepastdecadeofobservation(2009–2019),ischanged,with asmallershareofsolidfossilfuels(whosesharefallsfrom15%to11.4%)andoil

1ChallengesandOpportunitiesoftheEnergyTransition

(whichincreasedfrom38.1%to36.4%),mainlyinfavorofrenewablesources,which in2019represented15.3%ofprimaryenergyproduction(+5.2p.p.comparedto 2009).Atthesametime,theCO2 emissionsproducedinEUhavemoreorlessconstantlydecreasedoverthecourseofthepastdecade,reachingalevelof2400Mtin 2019,about12%lessthan10yearsearlier.

EnergysystemsintegrationistheagendaofEUasapossibleroutetoachieve theambitioustargetssetto2030and2050.Inthenearfutureuntil2030,inEU vision,theshareofRES,nuclearenergy,andcarbon-neutralgasesandliquidswill increasewithhighcontributiontogridstabilityanduninterruptedenergysupply. Newenergycarriersarebeingconsideredinenergy,industrial,andtransportapplications,suchashydrogenandothercarbon-neutralliquidsandgases.Additionally, thefutureenergysystemwillalsorelyonmuchbetterbalancingcapacitiesincludingbetterinterconnections,storagecapabilities,DR,low-carbonflexiblegeneration units,andeffectiveenergyconversionoptions(Power-to-X).Particularinterestis giventothehydrogenasanenergycarrier,whichwillbemainlyusedforthefollowingapplications:

● Energycarrierforindustrialapplications;

● μ-CHPsystemsbasedonfuelcellsforbuildings;

● Fuelformobility;

● Powergeneration;and

● Energystorage.

Theconceptofcouplingelectricitytootherformsofenergyhastraditionallybeen referredexclusivelytotheelectrificationofsectorssuchasheatingandtransport. WiththeCleanEnergyPackage,thisconcepthasbeenexpandedinordertoinclude Power-to-Xsystemsthat,startingfromtheelectricvector,involveotherenergyvectors.Theseapplicationscanprovideflexibilitytotheenergysystembymanagingto meetthedemandsforthermalenergy,fuels,andmobilitythroughPtH,PtG,and PtMtechnologies,respectively.

First,themarketreviewconcernstherulesrelatingtoelectricvehicles.Article33 oftheEMDII[9]statesthatMemberStatesmustprovidetheregulatoryframework necessarytofacilitatetheconnectionofpublicandprivatechargingpointstothe distributionnetworks.Also,thenewEPBD[14]aimstofacilitatetheintroduction ofelectricmobilitybyequippingbuildingswithinfrastructureforelectricvehicles. PursuanttoArticle8,MemberStatesmustprovideformeasurestosimplifythe installationofrechargingpointsinnewandexistingresidentialandnon-residential buildingsandprovidefortheovercomingofanyregulatoryobstacles.

Second,theREDII[10]providesafirstEuropeantargetforheatingandcooling fromrenewablesources.AccordingtoArticle23oftheREDII[10],MemberStates havethetasktoincreasetheirpercentageofrenewableheatby1.3%everyyearuntil 2030.Wasteheatandcoldcancontributeupto40%toobjective,whiledistrictheatingandcoolingwillhavetocontributewithanaverageannualincreaseinrenewable energiesofatleastonepercentagepoint.

Thelong-termvisionto2050iswelldefinedbyETIPSNET[2],whichconsiders theelectrificationofEuropeanenergysystemsasthebackboneofitssocietiesand

1.3PillarsfortheTransitionTowardIntegratedDecentralizedEnergySystems 11 markets.Inordertoachieveafullycarbon-freeenergysystem,itisneededtoexploit inthebestpossiblewayintegrationoptionsbetweenelectricityandgasnetworksas wellascountondailyorseasonalstoragesuchashydro,batteries,hotwaterseasonal storage,andPtGconversiontechnologies.Akeyroleinthefutureenergysystemwill alsobeplayedbydistributedenergyresourcesthataccordingtothisvisionwillbe exploitedfortheirfullpotential,byhelpingtomaximizetheresilienceofenergy supplyforelectricityandheatingandcoolingneeds.Thefutureintegratedenergy systemwillrelyonrenewableelectricitymainlyfromhydro,solar,wind,geothermal,andrenewableheatandcoolingfromsolar,biomass,biogas,andgeothermal, renewablegasasbiogasandrenewablefuelsasbiofuels.

1.3PillarsfortheTransitionTowardIntegrated DecentralizedEnergySystems

Thisbookaddressesthetopicofintegrateddecentralizedenergysystemsbyfocusingtheattentiononthepillarsdescribedbelowthatwillplayamajorroleinthe transitionofthetraditionalenergysystemstowardthisnewenergyparadigm.

Powerconversionplaysakeyroleinfutureintegratedenergysystems,where electricityenablesforaswitchofenergycarriersthrough Power-to-Xtechnologies,whichprovideenergystorageandsectorcouplingbyconvertingelectricity intochemicalenergyandheat,therebyallowingcircularityintotheenergysystem. Power-to-Xenergycanactasasinkforelectricitysurplusesbyusingtheavailable energyinacost-effectiveway.

Byenablingsectorcouplingwhileacceleratingcarbonneutraltransition, hydrogenasavector alsoplaysanessentialroleinintegratedenergysystems.Withhigh shareofvariablerenewables,theproductionofcarbon-freeenergycarriersashydrogenfromrenewableelectricitycoversanimportantroleforthedecarbonizationof theenergysystemasawhole.Theproductionofhydrogencanprovidesignificant flexibilitytothepowersystem,aswellas–mostimportantly–seasonalstorageof renewableelectricitybyblendinghydrogenintonaturalgasgrids.Hydrogenasa vectorcanbeseenasanelectricitystoragemethod(Power-to-X-to-Power),which cancontributetotheincreaseofstochasticrenewableelectricitypenetrationinto thegrid,butitalsorepresentsaversatilecross-vectormediumenablingthedeep decarbonizationofnon-electrifiedhard-to-abatesectorsasrenewablefuels,sector integration,andmobility.

Inanintegratedenergysystemwherethelocallyavailableenergyresourcesare usedfortheirfulleconomicpotential, storageinallformsandtypes playsacrucialrole.Energystoragecanprovidemultipleservicestotheenergysystemasa wholebystoringtheenergyproducedinexcessanddeliveringitondemand.Itcan smoothenthevariabilityofRES,makingthepowersystemmorereliableandflexible.Batteryenergystoragesystemsareconsideredamongthebestsuitedtechnologiesforshortandmid-termflexibilityservices,suchasfrequencyregulation,spinningreserve,peakshaving,etc.Long-termstorageservicesincludingseasonalstorageareneededinthepresenceofhighpenetrationlevelsofsolarandwindenergy

1ChallengesandOpportunitiesoftheEnergyTransition

production,andtheyaregenerallysuppliedbybulkenergystoragesystems,suchas pumped-hydroplantsormechanicalstoragefacilitiesandelectrochemicalenergy storage.Thermalstoragesolutionscanbeusedinseveralindustrialapplications aswellasdistrictheating,PtHapplications,etc.Besides,theyrepresentastrong supporttoheatingandcoolingelectrification.Theseapplicationsarecornerstone toenhancetheenergysystemcircularity,thankstotheircharacteristicsofclosing energycycleswithoutenergywaste:storingexcesselectricitythatwould,inanopen cycle,causethecurtailmentofrenewables,byconvertingittootherforms,enables newenergystreamsbendingoverthecycletowardusefulends,thusincreasingcircularity.

Digitalization isakeyenablerforintegrateddecentralizedenergysystemsby integratinginnovativetechnologiesintheelectricitysystemthroughinteroperable, standardizeddataarchitecturesandrelatedcommunicationforachievinghigher levelsofefficiency.Digitalizationimprovestheobservabilityofthepowersystem forstableandsecureoperationinthepresenceofhighsharesofRES,enabling advancedplanning,operation,protection,control,andautomationoftheenergy systems,throughtheavailabilityofreal-timeinformationthatimprovessystem balancingandresilienceatalltimescalesinthecaseofanyunforeseenandsudden event.InformationTechnologiesincludingsemanticdatamodels,BigDatamanagement,andArtificialIntelligencewillenabletheoptimizationandautomation ofprocessesandsupportoperators’decisions.Throughdigitalization,itwillbe possibletofacilitateservicesandachievefullintegrationofalltypesofenergy systems.Moreover,digitalizationisalsokeytoexploitthefullpotentialofactive consumerstocontributetotheeffectiveintegrationofRESinthepowersystem. ThemassiveintegrationofsmartmetersandHomeEnergyManagementSystems willallowtheimplementationofnewbusinessmodelsandaggregationschemes (e.g.energycommunities)thatexploittheflexibilityoftheactiveconsumers.

Smartmobility playsanimportantroleinacceleratingcarbonneutraltransition. WhensupportedbyhigherdeploymentofRES,itcontributeswithmultiplebenefits tothesustainabilityofthetransportsystem.Infact,electricvehiclesareexpected toplayaprimaryroleinthedecentralizedenergysystemandrepresentadriverfor increasingRESintegrationinthebuildingstomeettheiradditionalpowerdemand. Smartgrids alsosupportenergytransitionthroughreducingCO2 emissionsina cost-efficientway.Byoptimizingtheassetutilization,theyreducetheneedsfornew investments.Moreover,theyenablepenetrationofrenewablesandemergingand efficienttechnologies,therebyallowingminimizationofcostsandcarbonemissions. Anotherimportantbenefitrelatedtosmartgridsistheprovisionofreal-timeand monitoringcontrolthatallowsimprovingstability,resilience,andsecurityofthe powersystem.Lastbutnotleast,theyenhancethequalityofthesuppliedpower throughreducingcommercialandtechnicallosses.

Efficientenergyuseinbuildingsisanotherconstitutingfactorforintegratedenergysystems.Moreover,becauseoftheactivelocalenergygeneration (building-integratedgeneration)combinedwithenergyefficiencysolutions (e.g.insulationandefficientappliances),newbuildingsinmostcaseswillbe nearlyzero-energyandpossiblypositive-energybuildings.Employing

energy-efficientsolutionsandrenewableenergiesarecriticalfactorstomeetthe energyandenvironmentaltargetssetforthebuildingsector.Thefirstfactorcan reducethebuilding’senergyconsumption,whilethesecondonecanreducethe buildings’totalenergyintensity.Especially,positiveenergybuildingscanbeconsideredadvantageousforthedecarbonizationofthebuildingsectorandapromising pathwaytowardsustainableurbandevelopmentbecauseoftheirscalability potential,renewableenergyharnessingcapacityandhighenergyefficiency.

Lastbutnotleast, localenergycommunities willbecomeincreasinglyimportantinthetransitiontowardalow-orevencarbon-neutralenergysystem.EspeciallyintheEuropeancontext,theyrepresentanemergingparadigmwhereactive consumersandprosumersareengagedandplayanactiveroleinaggregatedforms throughrenewableenergycommunitiesandcitizenenergycommunities.Moreover, localenergycommunitiescanperfectlyrepresenttheconceptoflocalintegrated energysystems,which,characterizedbywell-definedboundaries,involvedifferent energytechnologiesandcarriersthatcanbeintegratedinordertooptimallyexploit thesynergiescomingfromthisinterplay,therebyenhancingenergyresourcesuse.

ListofAbbreviations

CHPcombinedheatandpower

DGdistributedgeneration

DoEdepartmentofenergy

DRdemandresponse

EHVextrahighvoltage

EMDenergymarketdirective

EPBDenergyperformanceofbuildingsdirective

EUEuropeanUnion

HVhighvoltage

IRENAInternationalRenewableEnergyAgency

PtGpower-to-gas

PtHpower-to-heat

REDrenewableenergydirective

REmaprenewableenergyroadmap

RESrenewableenergysources

SDGsustainabledevelopmentgoals

SRIsmartreadinessindicator

UNUnitedNations

References

1 McCollum,D.L.,Zhou,W.,Bertram,C.etal.(2018).Energyinvestmentneeds forfulfillingtheParisAgreementandachievingtheSustainableDevelopment Goals. Nat.Energy 3(7):589–599.

2 ETIPSNETVISION2050(2018).IntegratingSmartNetworksfortheEnergy Transition:ServingSocietyandProtectingtheEnvironment.

3 IRENA(2019). GlobalEnergyTransformation:ARoadmapto2050 (2019 edition).AbuDhabi:InternationalRenewableEnergyAgency.

4 ETIPSNET(2020).SectorCoupling:Concepts,State-of-the-artandPerspectives. WhitePaper,January2020.

5 Eid,C.,Koliou,E.,Valles,M.etal.(2016).Time-basedpricingandelectricity demandresponse:existingbarriersandnextsteps. Util.Policy 40:15–25.

6 CleanenergyforallEuropeanspackage.https://ec.europa.eu/energy/topics/ energy-strategy/clean-energy-all-europeans_en(accessed18October2021).

7 REGULATION(EC)No714/2009OFTHEEUROPEANPARLIAMENTAND OFTHECOUNCILof13July2009onconditionsforaccesstothenetwork forcross-borderexchangesinelectricityandrepealingRegulation(EC)No 1228/2003.

8 DIRECTIVE2009/72/ECOFTHEEUROPEANPARLIAMENTANDOFTHE COUNCILof13July2009oncerningcommonrulesfortheinternalmarketin electricityandrepealingDirective2003/54/EC.

9 Directive2019/944/EUontheinternalelectricitymarket.https://eur-lex.europa .eu/legal-content/EN/TXT/PDF/?uri=CELEX:32019L0944&from=EN(accessed 18October2021).

10 Directive2018/2001/EUonthepromotionoftheuseofenergyfromrenewable sources.https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX: 32018L2001&from=EN(accessed18October2021).

11 DIRECTIVE2009/28/ECOFTHEEUROPEANPARLIAMENTANDOFTHE COUNCILof23April2009onthepromotionoftheuseofenergyfromrenewablesourcesandamendingandsubsequentlyrepealingDirectives2001/77/EC and2003/30/EC.

12 Directive2018/2002onenergyefficiency.https://eur-lex.europa.eu/legal-content/ EN/TXT/PDF/?uri=CELEX:32018L2002&from=EN(accessed18October2021).

13 DIRECTIVE2012/27/EUOFTHEEUROPEANPARLIAMENTANDOF THECOUNCILof25October2012onenergyefficiency,amendingDirectives2009/125/ECand2010/30/EUandrepealingDirectives2004/8/ECand 2006/32/EC.

14 Directive2018/844ontheenergyperformanceofbuildings.https://eur-lex .europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32018L0844&from=IT (accessed18October2021).

15 Regulation(EU)2018/1999onthegovernanceoftheEnergyUnionandClimate Action.https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX: 32018R1999&from=EN(accessed18October2021).

16 AEuropeanGreenDealStrivingtobethefirstclimate-neutralcontinent. https://ec.europa.eu/info/strategy/priorities-2019-2024/european-green-deal_ en(accessed18October2021).

IntegratedEnergySystems:TheEngineforEnergy Transition

MarialauraDiSommaandGiorgioGraditi

ItalianNationalAgencyforNewTechnologies,EnergyandSustainableEconomicDevelopment,ENEA, DepartmentofEnergyTechnologiesandRenewableSources,Rome,Italy

2.1Introduction:theConceptofIntegratedEnergy System

Energysystemsplayanessentialroleintheeconomicandsocialdevelopment ofacountryandinthelifequalityofpeople[1,2].Withtheincreaseofenergy demandonaworldwidescale,depletionoffossilfuels,andgrowingenvironment protectionawarenessderivedbythelatestClimateConferenceCOP21,improving theefficiencyofenergyresourceusehasbecomeoneofthekeychallenges[3].In suchacontext,theEuropeanUnion(EU)hassetambitiousenvironmentaland energygoalstodesignalow-carbonenergysystembythemiddleofthetwenty-first century.TheEUclimateandenergyframeworkestablishestargetstoa40%reductioningreenhousegas(GHG)emissions(from1990levels),32%shareforrenewable electricity,and32.5%improvementinenergyefficiencytobeachievedby2030.

Thesetargetsbecomeevenmoreambitiousfor2050,withtheEnergyRoadmap 2050oftheEuropeanCommissionandtheEnergyUnionstrategysupportingthe aimoffullydecarbonizingtheEuropeaneconomybyreducingGHGemissionsin developedcountriesbelow80–95%of1990levelsby2050.Theseambitioustargets canbeachievedbydevelopingenergysystemssupportingtheimplementationof threeprimarygoals:mitigatingenvironmentalimpactsofenergysystems,creating affordableandmarket-orientedenergyservices,andensuringsecurity,reliability, andresilienceofenergysupply.

Mitigatingenvironmentalimpactsofenergysystemshasseveraldimensions, including:

● reducingGHGemissionsformitigationofclimatechange;

● monitoringsourcesofpollutionoriginatingfromactivitiesdirectlyorindirectly linkedtoenergysystems;and

● promotingacirculareconomy.

Thecreationofaccessibleandmarket-basedenergyservicescaninsteadbe achievedbyplacingtheso-calledprosumers,whoareatthesametimeproducers

andconsumersofenergy,atthecenteroftheenergysystem,whilepromotingtheir activeroleandmakingthemmoreresponsibleforenergyconsumption.

Inordertoguaranteethesecurity,reliability,andresilienceofenergysupply, thecreationofintegratedenergysystemsplaysacrucialrole.Alsoknownas multi-energysystemsorhybridenergysystems,themainideabehindthemisto movefromasingleenergycarriertomultipleenergycarriersinordertoexploit thesynergiesfromtheirinterplay,therebyincreasingtheefficiencyintheenergy resourcesused[4].

TheconceptofintegratedenergysystemsiswelldefinedintheETIPSNETVISION 2050[5]thatforeseesthisenergyparadigmfullyimplementedby2050.According tothisvision,thesesystemsarecharacterizedbytheintegratedmanagementofthe electricvector,themobility,theheatandcoolingvectorforspaceheatingandcooling,andthevarioustypesofstorage.Consideredas“asystemofasystems”and representedinFigure2.1,itcanbeseenasanintegratedinfrastructureforallenergy carrierswiththeelectricalsystemasabackbone,characterizedbyahighlevelof integrationbetweenallnetworksofenergycarriers,couplingelectricalnetworks withgasnetworks,heatingandcooling,supportedbyenergystorageandconversion processes.

Figure2.1 SchemeofanintegratedenergynetworkaccordingtoETIPSNETVision2050. Source:BasedonETIPSNET“VISION2050”[5].

Gastopower Powertogas

2.1Introduction:theConceptofIntegratedEnergySystem 17

Thekeyelementscharacterizingthisemergingenergyparadigmare:

● thefullinvolvementoftheenduserinthemanagementofthesystemitself.Under theconceptofintegratedenergysystems,citizensbecomeactiveconsumersand prosumers,usinglocalanduser-friendlyenergyexchanges,aswellaspeer-to-peer exchanges,forawiderangeofservicesandoptimalenergyprices.Notonlythat, buttheactiveroleofendusersisfullyimplementedinthemechanismsofdemand response,throughwhichtheyaremadeparticipantsinthemanagementofnetworkcontingencies,aswellasinreducingenergyconsumptionthroughapplicationssuchaszeroenergybuildingsorpromotingrenewableenergyprojects throughrenewableenergycommunities;

● theintegrationofallenergycarriersandtheadventofdistributedpoly-generation fullysuppliedbyrenewableenergysources(RES).Obviously,inthiscontext,storageinallitsformsandtypesplaysacrucialroleinordertodeal withthelargepenetrationofRES.Thelocallyavailableenergyresourcesare usedfortheirfulleconomicpotential,partlyreflectingtheupgradingneeds oftheelectricitytransmissionanddistributionnetworksandalsocontributingtomaximizingtheresilienceofsupplychannelsforheatingandcooling needs;

● theintegrationofdigitalizationenablingnewservicesforenergyconsumersas decentralizedcontroltechniques,peer-to-peerenergytrade,andplatformsfor dataexchangeandfastdecision-makingforallactorsoperatinginintegrated energysystems,therebyenablingadvancedoperationplanning,control,and automationofenergysystems;

● cross-sectorintegrationthroughwhichsectorssuchasheating,cooling,transportation,andindustryareallsuppliedwithlow-carbonenergy,thusreducing significantlyGHGemissions.Insuchcontext,thecross-sectorintegrationcan contributetothecost-efficientdecarbonizationoftheenergysystem,byvaluing synergypotentialsandinterlinkagesbetweendifferentpartsoftheenergy system.

Integratedenergysystemsrelyonsectorcouplingthatindicateslinkingthevariousenergycarriers–electricity,heat,cold,gas,andliquidfuels–witheachotherand withtheendusesectors,suchashouseholds,tertiarysectors,industry,andtransport.Theplanistodeployvariousexistingandemergingtechnologies,processes, andbusinessmodels,suchasinformationandcommunication(ICT)anddigitalization,smartgridsandmeters,andflexibilitymarkets.

Althoughrecentlegislationsandregulationsfullysupporttheimplementationof integratedenergyconcept,includingtheEuropeanGreenDeal[6]andCleanEnergy packageforallEuropean[7],fromthetechnicalpointofview,furtherstudiesonthe requirementsforenablingfulloperationofintegratedsystemsareneeded.Indeed, thecorefeatureoftheintegratedenergysystemparadigmistheintrinsicinterdependencyamongenergycarriersandsub-systemsbecauseoftheircorrelatedinteractions.Relevantoptimization,operation,andplanningneedtoconsiderthisaspect inordertoexploittheextendedflexibilityforenhancingtheefficiencyoftheenergy resourcesused[4].