城市净零路径研究——以苏州吴中区为例（英）-IRENAVIP专享VIP免费

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Supported by

SECTOR COUPLING

IN FACILITATING INTEGRATION

OF VARIABLE RENEWABLE

ENERGY IN CITIES

NET ZERO PATHWAYS FOR CITIES:

THE CASE STUDY OF WUZHONG

DISTRICT, SUZHOU, CHINA

Unless otherwise stated, material in this publication may be freely used, shared, copied, reproduced, printed

and/or stored, provided that appropriate acknowledgement is given of IRENA as the source and copyright

holder. Material in this publication that is attributed to third parties may be subject to separate terms of use and

restrictions, and appropriate permissions from these third parties may need to be secured before any use of such

material.

ISBN: 978-92-9260-425-7

IRENA (2022), Net-Zero Pathways for Cities: The Case Study of Wuzhong District, Suzhou, China, International

Renewable Energy Agency, Abu Dhabi.

About IRENA

The International Renewable Energy Agency (IRENA) serves as the principal platform for international

co-operation, a centre of excellence, a repository of policy, technology, resource and ﬁnancial knowledge, and a

driver of action on the ground to advance the transformation of the global energy system. An intergovernmental

organisation established in 2011, IRENA promotes the widespread adoption and sustainable use of all forms of

renewable energy, including bioenergy, geothermal, hydropower, ocean, solar and wind energy, in the pursuit

of sustainable development, energy access, energy security and low-carbon economic growth and prosperity.

www.irena.org

Acknowledgements

IRENA would like to express sincere appreciation to Empa for its technical contribution to the modelling

development and analyses. IRENA is also thankful to the experts who reviewed the report. Insightful comments

and constructive suggestions were provided by Jiejun Chen, Qian Chen, Hangping Pan and Zhihuang Sun (State

Grid Suzhou City and Energy Research Institute).

Special thanks go to Paul Komor, who provided helpful feedback and advice.

IRENA colleagues Prasoon Agarwal, Francisco Boshell, Imen Gherboudj, Jack Kiruja, Michael Renner, Elizabeth

Press and Nicholas Wagner provided valuable review and input.

IRENA is grateful for the support of Germany’s International Climate Initiative (IKI) project in producing this

publication.

IKI support

This report forms part of the Energy Solutions for Cities of the Future project, which is supported by the

International Climate Initiative (IKI). The German Federal Ministry for the Environment, Nature Conservation and

Nuclear Safety (BMU) supports this initiative on the basis of a decision adopted by the German Bundestag.

Contributing authors

This report was prepared, under the guidance of Dolf Gielen, by the sustainable urban energy team at IRENA’s

Innovation and Technology Centre. It was authored by Yong Chen (IRENA), Mashael Yazdanie, and Chenyu Zhou

(Empa), Weiyang Li, Weimin Xi and Chanxia Zhu (SGCERI), with additional support from Julien Marquant and

Fabia Miorelli (former IRENA colleagues).

Disclaimer

This publication and the material herein are provided “as is”. All reasonable precautions have been taken by IRENA to verify the

reliability of the material in this publication. However, neither IRENA nor any of its ocials, agents, data or other third-party

content providers provides a warranty of any kind, either expressed or implied, and they accept no responsibility or liability for

any consequence of use of the publication or material herein.

The information contained herein does not necessarily represent the views of all Members of IRENA. The mention of speciﬁc

companies or certain projects or products does not imply that they are endorsed or recommended by IRENA in preference to

others of a similar nature that are not mentioned. The designations employed, and the presentation of material herein, do not

imply the expression of any opinion on the part of IRENA concerning the legal status of any region, country, territory, city or

area or of its authorities, or concerning the delimitation of frontiers or boundaries.

NET ZERO PATHWAYS FOR CITIES:

THE CASE STUDY OF WUZHONG DISTRICT, SUZHOU, CHINA 3

TABLE OF CONTENTS

ABBREVIATIONS 5

EXECUTIVE SUMMARY 6

1. INTRODUCTION 9

1.1 China’s new carbon targets are guiding cities’ energy development 9

1.2 Wuzhong District: A pilot on the race to net-zero 11

1.3 Objectives of this report 13

2. METHODOLOGY 15

2.1 Model 15

2.2 Data constraints, estimation and assumptions 18

2.3 Limitations 33

3. MODELLING SCENARIOS AND RESULTS 35

3.1 Baseline case 35

3.2 Carbon policy 37

3.3 Sustainable development scenarios 39

3.4 Net-zero CO2 scenario 42

3.5 Pareto eciency 43

4. DISCUSSION 46

4.1 Integrated solar PV holds untapped potential for cities 46

4.2 Enhancing demand-side ﬂexibility in support of grid integration of renewables 48

4.3 Role of green hydrogen 49

4.4 Importance of sustainable urban energy planning 50

5. CONCLUDING REMARKS 53

REFERENCES 55

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SupportedbySECTORCOUPLINGINFACILITATINGINTEGRATIONOFVARIABLERENEWABLEENERGYINCITIESNETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA©IRENA2022Unlessotherwisestated,materialinthispublicationmaybefreelyused,shared,copied,reproduced,printedand/orstored,providedthatappropriateacknowledgementisgivenofIRENAasthesourceandcopyrightholder.Materialinthispublicationthatisattributedtothirdpartiesmaybesubjecttoseparatetermsofuseandrestrictions,andappropriatepermissionsfromthesethirdpartiesmayneedtobesecuredbeforeanyuseofsuchmaterial.ISBN:978-92-9260-425-7IRENA(2022),Net-ZeroPathwaysforCities:TheCaseStudyofWuzhongDistrict,Suzhou,China,InternationalRenewableEnergyAgency,AbuDhabi.AboutIRENATheInternationalRenewableEnergyAgency(IRENA)servesastheprincipalplatformforinternationalco-operation,acentreofexcellence,arepositoryofpolicy,technology,resourceandfinancialknowledge,andadriverofactiononthegroundtoadvancethetransformationoftheglobalenergysystem.Anintergovernmentalorganisationestablishedin2011,IRENApromotesthewidespreadadoptionandsustainableuseofallformsofrenewableenergy,includingbioenergy,geothermal,hydropower,ocean,solarandwindenergy,inthepursuitofsustainabledevelopment,energyaccess,energysecurityandlow-carboneconomicgrowthandprosperity.www.irena.orgAcknowledgementsIRENAwouldliketoexpresssincereappreciationtoEmpaforitstechnicalcontributiontothemodellingdevelopmentandanalyses.IRENAisalsothankfultotheexpertswhoreviewedthereport.InsightfulcommentsandconstructivesuggestionswereprovidedbyJiejunChen,QianChen,HangpingPanandZhihuangSun(StateGridSuzhouCityandEnergyResearchInstitute).SpecialthanksgotoPaulKomor,whoprovidedhelpfulfeedbackandadvice.IRENAcolleaguesPrasoonAgarwal,FranciscoBoshell,ImenGherboudj,JackKiruja,MichaelRenner,ElizabethPressandNicholasWagnerprovidedvaluablereviewandinput.IRENAisgratefulforthesupportofGermany’sInternationalClimateInitiative(IKI)projectinproducingthispublication.IKIsupportThisreportformspartoftheEnergySolutionsforCitiesoftheFutureproject,whichissupportedbytheInternationalClimateInitiative(IKI).TheGermanFederalMinistryfortheEnvironment,NatureConservationandNuclearSafety(BMU)supportsthisinitiativeonthebasisofadecisionadoptedbytheGermanBundestag.ContributingauthorsThisreportwasprepared,undertheguidanceofDolfGielen,bythesustainableurbanenergyteamatIRENA’sInnovationandTechnologyCentre.ItwasauthoredbyYongChen(IRENA),MashaelYazdanie,andChenyuZhou(Empa),WeiyangLi,WeiminXiandChanxiaZhu(SGCERI),withadditionalsupportfromJulienMarquantandFabiaMiorelli(formerIRENAcolleagues).DisclaimerThispublicationandthematerialhereinareprovided“asis”.AllreasonableprecautionshavebeentakenbyIRENAtoverifythereliabilityofthematerialinthispublication.However,neitherIRENAnoranyofitsofficials,agents,dataorotherthird-partycontentprovidersprovidesawarrantyofanykind,eitherexpressedorimplied,andtheyacceptnoresponsibilityorliabilityforanyconsequenceofuseofthepublicationormaterialherein.TheinformationcontainedhereindoesnotnecessarilyrepresenttheviewsofallMembersofIRENA.ThementionofspecificcompaniesorcertainprojectsorproductsdoesnotimplythattheyareendorsedorrecommendedbyIRENAinpreferencetoothersofasimilarnaturethatarenotmentioned.Thedesignationsemployed,andthepresentationofmaterialherein,donotimplytheexpressionofanyopiniononthepartofIRENAconcerningthelegalstatusofanyregion,country,territory,cityorareaorofitsauthorities,orconcerningthedelimitationoffrontiersorboundaries.NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA3TABLEOFCONTENTSABBREVIATIONS5EXECUTIVESUMMARY61.INTRODUCTION91.1China’snewcarbontargetsareguidingcities’energydevelopment91.2WuzhongDistrict:Apilotontheracetonet-zero111.3Objectivesofthisreport132.METHODOLOGY152.1Model152.2Dataconstraints,estimationandassumptions182.3Limitations333.MODELLINGSCENARIOSANDRESULTS353.1Baselinecase353.2Carbonpolicy373.3Sustainabledevelopmentscenarios393.4Net-zeroCO2scenario423.5Paretoefficiency434.DISCUSSION464.1IntegratedsolarPVholdsuntappedpotentialforcities464.2Enhancingdemand-sideflexibilityinsupportofgridintegrationofrenewables484.3Roleofgreenhydrogen494.4Importanceofsustainableurbanenergyplanning505.CONCLUDINGREMARKS53REFERENCES554FiguresFIGURE1:LocationofWuzhongDistrictinSuzhoucity12FIGURE2:Modelreferenceenergysystemdiagram19FIGURE3:Hourlyelectricitydemandprofile–industrialsector20FIGURE4:Hourlyelectricitydemandprofile–servicesector21FIGURE5:Hourlyelectricitydemandprofile–residentialsector21FIGURE6:Processheatingdemandprofile–industrialsector21FIGURE7:Spaceheatingdemandprofile–servicesector22FIGURE8:Spaceheatingdemandprofile–residentialsector22FIGURE9:Spacecoolingdemandprofile–servicesector23FIGURE10:Spacecoolingdemandprofile–residentialsector23FIGURE11:Hotwaterdemandprofile–servicesector24FIGURE12:Hotwaterdemandprofile–residentialsector24FIGURE13:GDPgrowthinWuzhongDistrict,2013-201725FIGURE14:NationalChinesepopulationscenarios25FIGURE15:PopulationgrowthfortheWuzhongDistrict26FIGURE16:Electricitydemandprojectionsacrosssectors26FIGURE17:Processheatdemandprojection–industrialsector27FIGURE18:BuildingareagrowthforWuzhongDistrict27FIGURE19:Spaceheatingdemandprojections–serviceandresidentialsectors28FIGURE20:Spacecoolingdemandprojections–serviceandresidentialsectors28FIGURE21:Hotwaterdemandprojections–serviceandresidentialsectors29FIGURE22:TotaldemandforallenergyservicesintheWuzhongDistrict29FIGURE23:Normalisedseasonalsolarradiationprofiles30FIGURE24:Biomasswastepotentialprojection30FIGURE25:Relativeefficiencyimprovementsforelectricalappliancesacrosssectors31FIGURE26:Carbonemissionfactorforgridelectricity32FIGURE27:Baselinescenario–electricityandheatproduction36FIGURE28:CPscenario–electricityandheatproduction38FIGURE29:SD-CO2Min–electricityandheatproduction39FIGURE30:SD-CostMin–electricityandheatproduction40FIGURE31:SD-CO2Mid–electricityandheatproduction41FIGURE32:SD-CO2Min-LD–electricityandheatproduction41FIGURE33:Net-zeroCO2emissionsscenario–electricityandheatproduction42FIGURE34:CostsversusCO2emissionsacrossscenariosandParetoefficiencycurve43TablesTABLE1:Modelstructuralscope16TABLE2:Modelenergyconversiontechnologyoptionsandassociatedoutputsorfunctions17TABLE3:Parametersappliedtocalculateannualresidentialhotwaterdemand23NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA5ABBREVIATIONSBCbaselinecaseBIPVbuilding-integratedphotovoltaicCCPcombinedcyclepowerplantCCScarboncaptureandstorageCHPcombinedheatandpowerplantCO2carbondioxideCPcarbonpolicyGDPgrossdomesticproductIGCCintegratedgasificationcombinedcycleNZCnet-zeroCO2emissionsPVphotovoltaicSDsustainabledevelopmentSGCERIStateGridCityandEnergyResearchInstitute6EXECUTIVESUMMARYIn2020,ChinesePresidentXiJinpingannounced,atthe75thUnitedNationsGeneralAssembly,thatChinawillaimtopeakcarbondioxide(CO2)emissionsbefore2030andachievecarbonneutralityby2060.Atthenationallevel,Chinahas–overthepastdecade–maderemarkableprogressinrenewableenergydevelopment,inparticularinsolarphotovoltaics(PVs)andwindpower.Bytheendof2020,renewableelectricityaccountedforaround30%oftotalelectricityoutputand42%ofnationalinstalledpowergenerationcapacity.Inspiteofthis,fossilfuelsremaindominantinChineseenergyuse,includinginthepowersectorandinend-usesectorssuchastransportation,buildingsandindustry.Cities,includingtheirsuburbanareas,wherethemajorityofthesesectors’activitiestakeplace,willthereforehaveanimportantroletoplayinachievingthegoalsannouncedbyPresidentXiJinping.In2020,about60%ofChinesepeoplelivedincities.Citiesalreadyconsume85%ofthetotalnationalenergysupplyinChinaandareresponsibleforaround70%oftotalnationalenergy-relatedCO2emissions.Yet,overthenextthreedecades,ithasbeenprojectedthatanother250millionpeoplewillbecomeurbandwellersinChina.Howcanlocaldecisionmakerssupportthenationalenergytransitionandtheachievementofthenationalclimateobjectiveswhilesustaininglocaleconomicandsocialdevelopment?ThisstudyusedtheWuzhongDistrictofSuzhoucityasacasestudytoexplorepathwaystowardsanet-zeroemissionsfuture,particularlyforthosecitieswherethepotentialforrenewableenergyproductionislessabundant.Thestudytookauniqueapproach.ThefirstquestionprobedwaswhatoptionsWuzhongwouldhaveifthedistrictusedconventionalemissionabatementtechnologiestoreduceitscarbonemissionsfromitscurrentenergymix.Considerationstakenintoaccountinansweringthisquestionincluded(a)theconstraintsdistrictgovernancemightfaceinmakingadramaticandsystemicchangeand(b)thedistrict’slimitedrenewableenergyresourcesanditsconstraintsonlanduseduetotheecologicalpreservationzoneitislocatedin.ThemodellingresultsandscenarioanalysesshowhowWuzhong’senergysystemmightevolveifthetechnologicaloptionsanddecarbonisationstrategiesare,toalargeextent,confinedtoconventionaltechnologicalpathways.Cost-optimalscenariosdemonstratesignificantlylowerlocalinstalledcapacities,astheyrelyheavilyongridimports.Carbon-optimalscenariosdemonstratesignificantlyhigherinvestmentsingas,carboncaptureandstorage(CCS),ground-NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA7orwater-sourceheatpumps,andsolarconversiontechnologies,makingthesescenariosmorecostly.Themodellingexerciseaimedtohelplocaldecisionmakersunderstandthelimitationsofthebusiness-as-usualapproachandwhytransformativemeasuresmightbeneeded.Inaddition,themodelling-derivedresultsindicatethatWuzhongwouldhavetorelyonCCSfordecarbonisingnaturalgasandcoalifitfocusedondecarbonisationofitsowngenerationcapacitytoachievenet-zero.Inlessambitiousscenarios,naturalgasisgivenanimportantroletoplay.ThesemodellingresultsmightnotbealignedwiththeChineseoverallpolicydirectionandmultipleconstraintsthatmayexistinChina,includinglimitedpotentialofnaturalgasresources,lackofclarityoncarbonstoragecapacityintheregion,andthetechnologyrisksofCCS.Hence,theoveralloutlookforthesupplyofnaturalgaswouldneedtobefurtherdiscussed,asthedemandfornaturalgasnationwideisexpectedtogrowdramaticallyfollowingthephasingdownofcoalconsumption.Also,adetailedfeasibilityanalysisofCCStechnologiesintheSuzhouareaneedstobeconducted.Giventheabove,theextenttowhichWuzhongcanadoptadvancedrenewableenergytechnologies–suchasbuilding-integratedphotovoltaic(PV),city-integratedapplicationsofsolarPV,andinnovativesolutionssuchasextractingcoldenergyfromwatersupplyfacilities–iscrucialtoincreasingtheuptakeofrenewables.Althoughwasteenergyresources(mainlybiomassandmunicipalsolidwastes)arefullyutilisedineveryyearofeverymodelledscenario,someadvancedtechnologiesmightenablebiodegradablefeedstocktobeusedinamoreefficientway,whichmightalsoexpandthelocalresourcespectrum;thisoptioncouldbeusedinadditiontoimportingunderutilisedwastesfromneighbouringdistricts.Thelocalgeothermalpotentialandtheapplicabilityofadvancedtechnologiesfordirectuseofgeothermalresourcesarealsoworthinvestigating.Inallscenarioswiththeconventionalemissionabatementapproach,naturalgasisgivenanimportantroletoplay,undertheassumptionthatthecarbonemissionfactorsoftheelectricityimportedfromthegridtoWuzhongDistrictarehigherthanthoseassociatedwithlocalnaturalgas-basedelectricitygeneration.However,thegridelectricitycouldbedecarbonisedfaster,withgreatersharesofsolarPVandwindpowerbeingintegratedintothegrid,ifcitiescouldsupportgridoperationwithmoredemand-sideflexibility.Thiswill,inreturn,affecthowcitiesrespondtotheparadigmchangeintheChinesepowersectorandwillconsequentiallyaffectthecarbonemissionfactorsofnationalandregionalgridelectricitytoWuzhong.Thesecondstepofthestudylookedatstrategicareasenablingexpansionofthedecarbonisationoptionspresentedinthemodellingresults:building-integratedPV,demand-sideflexibility,greenhydrogenandurbanenergyplanning.TheseareasareapplicablenotonlyforWuzhongbutingeneralformanydistrictsandcitieslikeWuzhongwithmoderatelocalrenewableenergyresourcesandrelativelyhighenergydemand.Certainly,thesestrategicareasdonotconstituteanexhaustivelist,buttheydohighlightthemostrelevantaspectsthatsuchcitiesordistrictsshouldlookintoandadjusttosuitthecharacteristicsoftheirlocalities.Overall,theChineseleadershiphasboosteditsambitionandsteppedupitseffortstoaddresstheclimatechallenges.Citieswilltakethisasguidanceandmakecorrespondingstrategiesandactionsplanstocontributeasmuchastheycantoachievingthenationalcarbonpeakby2030andcarbonneutralityby2060.However,theactionstheytakeandthedecisionstheymakeshouldbebasedontheirresources.Thosewithoutabundantlocalrenewableenergyresourcescouldexploreotheroptionswiththeaimofachievingnet-zeroforChinesecitiesinacollectiveandcollaborativefashion.8©DanielHanscom/GettyImages1NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA9INTRODUCTIONWiththenear-universaladoptionin2015oftheParisAgreement–aninternationaltreatyonclimatechange–reachingnet-zeroemissionofanthropogeniccarbondioxide(CO2)around2050hasbecomethekeydriverfortheglobalenergytransition(IPCC,2018;UNFCCC,n.d.).Citieswillplayacriticalroleinreducingemissionsastheyareresponsibleforaroundthree-quartersofglobalenergyuseandCO2emissions(Edenhoferetal.,2014).Citieswould,inreturn,berewardedwithnewopportunitiesforindustrialandbusinessdevelopment,aswellasjobcreation,generatedbyimplementinginnovativesolutionsandredesigningurbaninfrastructuretounlockpotentialforcarbonemissionsreduction(IRENA,2020a).1.1China’snewcarbontargetsareguidingcities’energydevelopmentFiveyearsafterjoiningtheParisAgreement,ChinesePresidentXiJinpingannounced,atthe75thUnitedNationsGeneralAssembly,thatChinawillaimtoachievecarbonneutrality1by2060andpeak(energy-related)CO2emissionsbefore2030.Theseareknownasthe“dualcarbongoals”or“30-60goals”inChina.TheysendastrongsignalofChina’scommitmenttoacceleratingeffortstoaddressclimateissuesundertheglobalframeworksetoutbytheParisAgreement.Overthepastdecade,Chinahasmaderemarkableprogressinrenewableenergydevelopment,inparticularinsolarphotovoltaics(PVs)andwindpower.Bytheendof2020,renewableelectricityaccountedforaround30%oftotalelectricityoutputand42%ofnationalinstalledpowergenerationcapacity,accordingtotheChineseNationalEnergyAdministration.However,fossilfuelsremaindominantinChineseenergyuse,aselectricitymakesuponlyslightlymorethanone-quarteroffinalenergyuseatpresent.Therefore,decarbonisingend-usesectorssuchastransportation,buildingsandindustrythroughelectrificationandthroughsubstitutionoffossilfuelswithrenewable-basedenergycarrierswillbecrucialforChinatoachieveitsdualcarbongoals.Cities,includingtheirsuburbanareas,wherethemajorityofthekeyend-usesectors’activitiestakeplace,willhaveanimportantroletoplay.1.Coveringallgreenhousegases.10In2020,about60%ofChinesepeoplelivedincities.Overthenextthreedecades,itisprojectedthatanother250millionpeopleinChinawillbecomeurbandwellers(CNBS,2021).Thissuggeststhatbothenergyconsumptionandcarbonemissionswillincreaseinkeepingwiththegrowingurbanisationifsubstantialmeasuresarenottaken.Theimplicationsaresignificant,giventhatcitiesalreadyconsume85%ofthetotalnationalenergysupplyinChinaandareresponsibleforaround70%oftotalnationalenergy-relatedCO2emissions(McKinsey&Company,2021;SGCERI,2019).Themajorchallengethusliesinhowtosignificantlyreduceemissionswhileprovidingenergytogrowingurbanpopulations,giventhatfossilfuelsarestillthedominantsourceofenergysupplyinChina.TheChineseGovernmentisdevelopingmoredetailedguidanceforsubnationalgovernmentsandsectorstofollowindevisingtheirownactionplans.Decarbonisationofthebuildingsectorandthetransportsectorisexpectedtobeakeyareaoffocusundertheguidancetobeissuedsoon(GovernmentofChina,2021).Thishasprovidedcitiesaclearpolicydirectionfortheirfutureurbanplanningandinfrastructuredevelopment.Yet,formany,thequestionishowandtowhatextentChinesecitiescancapitaliseonsuchopportunities.Amajorchallengeisthemismatchbetweenthegeographicaldistributionoftheresourcesandthedemandforenergyservices.Muchoftheexcellentrenewableenergyresources–notably,solarandonshorewindandhydropower–arelocatedinthenorthernandwesternpartsofChina,whilethedemand(orloadcentres),likecities,isconcentratedintheeasternandsouthernregions.Therefore,itwouldbeeasierforthenorthernandwesterncitieswithabundantrenewablestodecarbonisetheirenergysupplyandproviderenewableelectricitytotheotherregions,ifthetransmissioncapacitypermits.Zhangjiakoucityisonesuchexample(seeBox1).FormanycentralandeasternChinesecities(exceptforsomecoastalcitieswithdecentoffshorewindenergypotential),thelocalpotentialforrenewableenergyresourcesismodest;furthermore,theavailablelandforthedeploymentofutility-scalerenewableenergysystemsislimited.Nevertheless,thankstotheirgeographicproximitytotheloadcentresandcontinueddeclineincost,therearestillsomecitieswherelocalrenewable-baseddistributedenergysystemspresentcompellingoptions.However,manycitieshavetorelyon“imported”renewableelectricityviathenationalorregionalgridsasakeystrategyforachievingnet-zeroemissions.Inreturn,thosecitiescanprovidegreaterflexibilitytoassisttheintegrationofvariablerenewableenergysourcesbyincreasingelectrificationinend-usesectorsandbyupgradinglocalpowergridsandenergymanagementsystemswithdigitaliseddevicesandintelligentcontrols.Forexample,insomecitiesglobally,electricvehiclesandtwo-andthree-wheelershavebeenusedtoreducedependencyonfossil-derivedtransportfuelsaswellastodecarbonisethetransportationsector.Chinahasbeenmakingsteadyprogressintheelectrificationofthetransportsector.Power-to-heatisanotherareawherecitieshavetakenadvantageofsurplusrenewableelectricitytoreduceemissionsfromtheheatingsector.Therefore,itiscrucialforlocalauthoritiestodevelopalong-termenergytransitionstrategy.Suchastrategyisvitaltomakingforward-lookinginvestmentdecisionstodaytoavoidlock-ineffectsandfuturestrandedassets.NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA111.2WuzhongDistrict:Apilotontheracetonet-zeroWuzhong,locatedinthecityofSuzhou(illustratedinFigure1),isarapidlydevelopingdistrictwithapopulationofapproximately1.1million(accountingfor10%ofSuzhou’stotalpopulation).Thedistricthasanareaof2231squarekilometres(km2),ofwhichthelandareais745km2andtherestisLakeTai.Eighty-sevenpercentofthetotalareaisclassifiedasanecologicalconservationarea,including61%ofthelandarea.Forconservationareas,stricterenvironmentalassessmentproceduresandenvironmentalregulationsapplyforanytypeofdevelopment.Therestrictionsonlandusehavealsosignificantlylimitedtheavailabilityoflandforthedeploymentofrenewableenergysystems.Thishasnarrowedtheoptionsforusinglocalrenewableenergyresources,whicharealreadylimitedcomparedwiththoseinthenorthernandwesternareasofChina.BOX1:Zhangjiakou’senergytransformationwithsolarandwindZhangjiakouisamedium-sizedChinesecityof4.4millionpeoplelocatedinnorthwestHebeiProvince,adjacenttoBeijing.Thecityisabundantinrenewableenergyresources,includinganestimatedtechnicalresourcepotentialof30gigawatts(GW)forsolarphotovoltaicsand40GWforwind.Overthepastdecade,thecityhassteppedupitseffortstodeployrenewableenergysystems.In2017,renewablesaccountedfor73%ofthetotalinstalledcapacityinZhangjiakouandforaround45%ofthetotalelectricityoutput.Nevertheless,muchofthepotentialhasyettobeexploited.Intermsoffutureenergydemand,uncertaintyremainsregardingtheshapingandimplementationofZhangjiakou’sindustrialrestructuringstrategy,theelectrificationofsomeend-usesectors,improvementsinenergyefficiency,andtheenhancementandexpansionoflocalandregionalpowergrids.Overall,increasinglocaluseofrenewablesrequiresgreaterapplicationofinnovativeend-usetechnologiesinconcertwithrenewableenergygeneration.ThestudyZhangjiakouUrbanEnergyTransformation2050hasshownthatbecauseZhangjiakouhasundertakenaninitiativetoupgradeitscurrentindustrialsectors–atransformativemovetoanewgenerationofindustrialdevelopmentforthecity–urbanenergysystemplanningmustbestrategicallyharmonisedwithindustrialsectordevelopmenttoensurethatthenewenergydemandcanbemetasmuchaspossiblebyrenewables.ThedemandforelectricityneededtoproducehydrogenfromrenewableswillincreaseinZhangjiakou.Inaddition,smartmanufacturingwillsubstituteforconventionalproductionfacilities,offeringbetterenergyandenvironmentalperformance.Forenergyproduction,includingofelectricityandheat,generationislocatedascloseaspossibletotheloadstoreducelossesduringtransmission.Withsufficientlyforward-lookingstrategicplanning,Zhangjiakoucanofferuniqueopportunitiesforbusinessestoreducetheirenvironmentalimpactthroughscaled-upuseofrenewableenergysources.Source:IRENA,2019a.12Thedistrictisdividedintofourzones:theLakeTaitouristiczone,theeconomicandtechnologydevelopmentzone,theagriculturalzone,andthehigh-techindustrialzone.TheindustrialandservicesectorsarethekeypillarsofWuzhong’seconomicdevelopment,drivinggrossdomesticproduct(GDP)growthoverthepastyearsataratehigherthanthenationalaverage.DuepartlytohighservicesectorsharesinitseconomicstructurecomparedwithotherdistrictsinSuzhou,Wuzhong’senergyintensityperunitofGDPisabout10%lowerthanthecityaverage.Nevertheless,ithastwoenergy-intensiveindustries:chemicalfibreproductionandferrousmetalprocessing.TheirsharesinthetotalenergyconsumptionofWuzhongarerathermodest,at10%and12%,respectively,becauseoftheirsmallscalesincapacity.Bycontrast,theelectronicequipmentmanufacturingindustryandthetextileindustry,whicharelowinenergyintensity,eachaccountfor25%ofthedistrict’stotalenergyuse,asaresultoftheirrelativelylargerproductionscales(WuzhongDRC,2020).Thedistrictanticipatescontinuedindustrialgrowthinthecomingyears,withafocusonhigh-techsectorssuchasrobotics,smartmanufacturingandthebio-medicalindustry,whileplacinghighpriorityonecologicalpreservationtoadvanceWuzhong’sgreendevelopmentstrategy.Decarbonisingthedistrict’senergymixremainsapriority.Assuch,WuzhongDistricthastheopportunitytobecomeamodelcommunityintheracetonet-zero,contributingtotherealisationofthenationaldualcarbongoals.FIGURE1:LocationofWuzhongDistrictinSuzhoucitySource:https://en.wikipedia.org/wiki/Suzhou.Disclaimer:Thismapisprovidedforillustrationpurposesonly.BoundariesandnamesshownonthismapdonotimplyanyendorsementoracceptancebyIRENA.LakeTaiWuzhongDist.SuzhouIndust.parkNETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA131.3ObjectivesofthisreportTheoverallobjectiveofthisreportistoprovideaframeworkfordiscussionthatfocusesonstrategies,technologiesandmeasurestodecarbonisetheenergysystematthedistrictlevel.Thisframeworkcanhelpurbanenergyplanningdecisionmakersatthedistrictleveltoengageinbalanceddiscussionsaboutincreasingsustainableenergydevelopmenttowardsthecarbonneutralitytarget,preferablyreachingtheobjectiveofbecominganet-zerocarbonemissionsdistrict.Therecommendationsofferedinthisreportaresuggestiveratherthanprescriptive,asthesituationinChinaisratherdynamicandenergytransitiontechnologiesarerapidlyevolvingglobally.Itisimportanttoremainflexiblewhendevelopingalonger-termstrategy.Thespecificobjectivesofthisreportareto:a.ProvideWuzhongDistrictwithasuiteofstrategicareasandspecificactionsthatthelocalauthoritiesandtheirenergyadvisorscanconsiderastheydeveloptheirsustainablelong-termenergyandurbanplanningstrategy.Therecommendationsfacilitateachievingcarbonreductiongoals(carbon-peakingandcarbonneutrality)bymaximisingtheuseoflocalrenewableenergyresourcesandincreasingtheshareofrenewableelectricityonaregionallevel.Thedistrictwouldneedtoprovidegreaterdemand-sideflexibilitythroughsectorcouplingandenhancedintelligenceofitsenergymanagementsystemstosupportthegridoperations.b.PresentauniquemethodologythatcouldbeadoptedbyotherdistrictsandcitiesinChineseregionswhererenewableenergyresourcesarenotonthetoptierintermsofpotentialorwheretherearemanyrestrictionsoncities’abilitiestoexploitsuchresources(e.g.restrictionsforecologicalprotection).14©RichardBradford/shutterstock.com2NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA15METHODOLOGYThisstudytakesatwo-stepapproachtoaddressthechallengesthatWuzhongDistrictfacesduringitstransitiontowardsanet-zerocarbonfuture.ThefirststepistoexplorewhatoptionsWuzhongwouldhaveifthedistrictusedconventionalemissionabatementtechnologiestoreduceitscarbonemissions,consideringWuzhong’slimitedpotentialforlocalrenewableenergyresourcesanditscurrentlydominantfossilfuelconsumption.Along-termoptimisationenergysystemmodelwasbuilttoconstructmultipleplanningscenarios.Thescenarioresultsshowhowtheemissionsfromthecurrentgenerationfleetcanbereducedasmuchaspossiblethroughconventionalapproachessuchasefficiencyimprovements,fuelswitching,andmodestincreasesintheuseoflocalrenewableenergyresources.Thiswillhelplocaldecisionmakersunderstandthelimitationsofthebusiness-as-usualapproachandwhytransformativemeasuresmightbeneeded.Thesecondstepfocusesondiscussionofasuiteofemerginginnovativesolutionsthatcouldhelpthedistrictfurtherchangecoursetowardsalowtonet-zerocarbonenergysystem.ThisisfollowedbygeneralrecommendationstoWuzhongonaddressingchallengesintheseareas.2.1ModelModelbuiltforWuzhongDistrictAlong-termenergysystemmodeloftheWuzhongDistrictwasbuiltusingOSeMOSYStoidentifylow-carbonemissionplanningpathwaysunderdifferentscenarios.Themodelaimstoprovideanalyticalinsightsintolong-termtechnologycapacityinvestmentanddispatchplanningfortheenergysystemundercostandcarbonminimisationobjectives.Thecostandcarbonminimisationobjectivesarespecifiedasfollows:yo-stepapproachtoaddressthechallengesthatWuzhongDistrictfacesduringitsnet-zerocarbonfuture.ThefirststepistoexplorewhatoptionsWuzhongwouldedconventionalemissionabatementtechnologiestoreduceitscarbonemissions,ng’slimitedpotentialforlocalrenewableenergyresourcesanditscurrentlylconsumption.Along-termoptimisationenergysystemmodelwasbuilttoanningscenarios.Thescenarioresultsshowhowtheemissionsfromthecurrentnbereducedasmuchaspossiblethroughconventionalapproachessuchasents,fuelswitching,andmodestincreasesintheuseoflocalrenewableenergyhelplocaldecisionmakersunderstandthelimitationsofthebusiness-as-usualansformativemeasuresmightbeneeded.usesondiscussionofasuiteofemerginginnovativesolutionsthatcouldhelpthegecoursetowardsalowtonet-zerocarbonenergysystem.ThisisfollowedbyationstoWuzhongonaddressingchallengesintheseareas.hongDistrictsystemmodeloftheWuzhongDistrictwasbuiltusingOSeMOSYStoidentifylow-nningpathwaysunderdifferentscenarios.Themodelaimstoprovideanalyticalrmtechnologycapacityinvestmentanddispatchplanningfortheenergysystemonminimisationobjectives.minimisationobjectivesarespecifiedasfollows:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁=�(1+𝑑𝑑𝑑𝑑)𝑌𝑌𝑌𝑌−𝑖𝑖𝑖𝑖∗𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇=�𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦esentvalueofthetotalcostmissionsfmodellingyearsearwhere:2.MethodologyThisstudytakesatwo-stepapproachtoaddressthechallengesthatWtransitiontowardsanet-zerocarbonfuture.ThefirststepistoexplohaveifthedistrictusedconventionalemissionabatementtechnologieconsideringWuzhong’slimitedpotentialforlocalrenewableenedominantfossilfuelconsumption.Along-termoptimisationenerconstructmultipleplanningscenarios.Thescenarioresultsshowhowgenerationfleetcanbereducedasmuchaspossiblethroughcoefficiencyimprovements,fuelswitching,andmodestincreasesinthresources.Thiswillhelplocaldecisionmakersunderstandthelimiapproachandwhytransformativemeasuresmightbeneeded.Thesecondstepfocusesondiscussionofasuiteofemerginginnovatdistrictfurtherchangecoursetowardsalowtonet-zerocarbonengeneralrecommendationstoWuzhongonaddressingchallengesinth2.1ModelModelbuiltforWuzhongDistrictAlong-termenergysystemmodeloftheWuzhongDistrictwasbuiltucarbonemissionplanningpathwaysunderdifferentscenarios.Theminsightsintolong-termtechnologycapacityinvestmentanddispatchundercostandcarbonminimisationobjectives.Thecostandcarbonminimisationobjectivesarespecifiedasfollows:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁=�(1+𝑑𝑑𝑑𝑑)𝑌𝑌𝑌𝑌−𝑖𝑖𝑖𝑖∗𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇=�𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦where:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁isthenetpresentvalueofthetotalcost𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇isthetotalemissions𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦isthesetofmodellingyears𝑌𝑌𝑌𝑌isthestartingyear𝑑𝑑𝑑𝑑istheannualdiscountrate𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖isthetotalsystemcostinyear𝑖𝑖𝑖𝑖𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖isthetotalemissionsinyear𝑖𝑖𝑖𝑖.Theobjectivefunction(totalcostand/orcarbon)isminimisedsubjeisthenetpresentvalueofthetotalcost2.MethodologyThisstudytakesatwo-stepapproachtoaddressthechallengesthatWtransitiontowardsanet-zerocarbonfuture.ThefirststepistoexplohaveifthedistrictusedconventionalemissionabatementtechnologieconsideringWuzhong’slimitedpotentialforlocalrenewableenedominantfossilfuelconsumption.Along-termoptimisationenerconstructmultipleplanningscenarios.Thescenarioresultsshowhowgenerationfleetcanbereducedasmuchaspossiblethroughcoefficiencyimprovements,fuelswitching,andmodestincreasesinthresources.Thiswillhelplocaldecisionmakersunderstandthelimiapproachandwhytransformativemeasuresmightbeneeded.Thesecondstepfocusesondiscussionofasuiteofemerginginnovatdistrictfurtherchangecoursetowardsalowtonet-zerocarbonengeneralrecommendationstoWuzhongonaddressingchallengesinth2.1ModelModelbuiltforWuzhongDistrictAlong-termenergysystemmodeloftheWuzhongDistrictwasbuiltucarbonemissionplanningpathwaysunderdifferentscenarios.Theminsightsintolong-termtechnologycapacityinvestmentanddispatchundercostandcarbonminimisationobjectives.Thecostandcarbonminimisationobjectivesarespecifiedasfollows:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁=�(1+𝑑𝑑𝑑𝑑)𝑌𝑌𝑌𝑌−𝑖𝑖𝑖𝑖∗𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇=�𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦where:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁isthenetpresentvalueofthetotalcost𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇isthetotalemissions𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦isthesetofmodellingyears𝑌𝑌𝑌𝑌isthestartingyear𝑑𝑑𝑑𝑑istheannualdiscountrate𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖isthetotalsystemcostinyear𝑖𝑖𝑖𝑖𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖isthetotalemissionsinyear𝑖𝑖𝑖𝑖.Theobjectivefunction(totalcostand/orcarbon)isminimisedsubjespecifiedtoincludeboundsontechnologycapacities,operationaisthetotalemissions2.MethodologyThisstudytakesatwo-stepapproachtoaddressthechallengesthatWtransitiontowardsanet-zerocarbonfuture.ThefirststepistoexplohaveifthedistrictusedconventionalemissionabatementtechnologieconsideringWuzhong’slimitedpotentialforlocalrenewableenedominantfossilfuelconsumption.Along-termoptimisationenerconstructmultipleplanningscenarios.Thescenarioresultsshowhowgenerationfleetcanbereducedasmuchaspossiblethroughcoefficiencyimprovements,fuelswitching,andmodestincreasesinthresources.Thiswillhelplocaldecisionmakersunderstandthelimiapproachandwhytransformativemeasuresmightbeneeded.Thesecondstepfocusesondiscussionofasuiteofemerginginnovatdistrictfurtherchangecoursetowardsalowtonet-zerocarbonengeneralrecommendationstoWuzhongonaddressingchallengesinth2.1ModelModelbuiltforWuzhongDistrictAlong-termenergysystemmodeloftheWuzhongDistrictwasbuiltucarbonemissionplanningpathwaysunderdifferentscenarios.Theminsightsintolong-termtechnologycapacityinvestmentanddispatchundercostandcarbonminimisationobjectives.Thecostandcarbonminimisationobjectivesarespecifiedasfollows:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁=�(1+𝑑𝑑𝑑𝑑)𝑌𝑌𝑌𝑌−𝑖𝑖𝑖𝑖∗𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇=�𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦where:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁isthenetpresentvalueofthetotalcost𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇isthetotalemissions𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦isthesetofmodellingyears𝑌𝑌𝑌𝑌isthestartingyear𝑑𝑑𝑑𝑑istheannualdiscountrate𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖isthetotalsystemcostinyear𝑖𝑖𝑖𝑖𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖isthetotalemissionsinyear𝑖𝑖𝑖𝑖.Theobjectivefunction(totalcostand/orcarbon)isminimisedsubjespecifiedtoincludeboundsontechnologycapacities,operationaisthesetofmodellingyears2.MethodologyThisstudytakesatwo-stepapproachtoaddressthechallengesthatWtransitiontowardsanet-zerocarbonfuture.ThefirststepistoexplohaveifthedistrictusedconventionalemissionabatementtechnologieconsideringWuzhong’slimitedpotentialforlocalrenewableenedominantfossilfuelconsumption.Along-termoptimisationenerconstructmultipleplanningscenarios.Thescenarioresultsshowhowgenerationfleetcanbereducedasmuchaspossiblethroughcoefficiencyimprovements,fuelswitching,andmodestincreasesinthresources.Thiswillhelplocaldecisionmakersunderstandthelimiapproachandwhytransformativemeasuresmightbeneeded.Thesecondstepfocusesondiscussionofasuiteofemerginginnovatdistrictfurtherchangecoursetowardsalowtonet-zerocarbonengeneralrecommendationstoWuzhongonaddressingchallengesinth2.1ModelModelbuiltforWuzhongDistrictAlong-termenergysystemmodeloftheWuzhongDistrictwasbuiltucarbonemissionplanningpathwaysunderdifferentscenarios.Theminsightsintolong-termtechnologycapacityinvestmentanddispatchundercostandcarbonminimisationobjectives.Thecostandcarbonminimisationobjectivesarespecifiedasfollows:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁=�(1+𝑑𝑑𝑑𝑑)𝑌𝑌𝑌𝑌−𝑖𝑖𝑖𝑖∗𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇=�𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦where:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁isthenetpresentvalueofthetotalcost𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇isthetotalemissions𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦isthesetofmodellingyears𝑌𝑌𝑌𝑌isthestartingyear𝑑𝑑𝑑𝑑istheannualdiscountrate𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖isthetotalsystemcostinyear𝑖𝑖𝑖𝑖𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖isthetotalemissionsinyear𝑖𝑖𝑖𝑖.Theobjectivefunction(totalcostand/orcarbon)isminimisedsubjespecifiedtoincludeboundsontechnologycapacities,operationaisthestartingyear2.MethodologyThisstudytakesatwo-stepapproachtoaddressthechallengesthatWtransitiontowardsanet-zerocarbonfuture.ThefirststepistoexplohaveifthedistrictusedconventionalemissionabatementtechnologieconsideringWuzhong’slimitedpotentialforlocalrenewableenedominantfossilfuelconsumption.Along-termoptimisationenerconstructmultipleplanningscenarios.Thescenarioresultsshowhowgenerationfleetcanbereducedasmuchaspossiblethroughcoefficiencyimprovements,fuelswitching,andmodestincreasesinthresources.Thiswillhelplocaldecisionmakersunderstandthelimiapproachandwhytransformativemeasuresmightbeneeded.Thesecondstepfocusesondiscussionofasuiteofemerginginnovatdistrictfurtherchangecoursetowardsalowtonet-zerocarbonengeneralrecommendationstoWuzhongonaddressingchallengesinth2.1ModelModelbuiltforWuzhongDistrictAlong-termenergysystemmodeloftheWuzhongDistrictwasbuiltucarbonemissionplanningpathwaysunderdifferentscenarios.Theminsightsintolong-termtechnologycapacityinvestmentanddispatchundercostandcarbonminimisationobjectives.Thecostandcarbonminimisationobjectivesarespecifiedasfollows:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁=�(1+𝑑𝑑𝑑𝑑)𝑌𝑌𝑌𝑌−𝑖𝑖𝑖𝑖∗𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇=�𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦where:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁isthenetpresentvalueofthetotalcost𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇isthetotalemissions𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦isthesetofmodellingyears𝑌𝑌𝑌𝑌isthestartingyear𝑑𝑑𝑑𝑑istheannualdiscountrate𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖isthetotalsystemcostinyear𝑖𝑖𝑖𝑖𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖isthetotalemissionsinyear𝑖𝑖𝑖𝑖.Theobjectivefunction(totalcostand/orcarbon)isminimisedsubjespecifiedtoincludeboundsontechnologycapacities,operationaistheannualdiscountrate2.MethodologyThisstudytakesatwo-stepapproachtoaddressthechallengesthatWtransitiontowardsanet-zerocarbonfuture.ThefirststepistoexplohaveifthedistrictusedconventionalemissionabatementtechnologieconsideringWuzhong’slimitedpotentialforlocalrenewableenedominantfossilfuelconsumption.Along-termoptimisationenerconstructmultipleplanningscenarios.Thescenarioresultsshowhowgenerationfleetcanbereducedasmuchaspossiblethroughcoefficiencyimprovements,fuelswitching,andmodestincreasesinthresources.Thiswillhelplocaldecisionmakersunderstandthelimiapproachandwhytransformativemeasuresmightbeneeded.Thesecondstepfocusesondiscussionofasuiteofemerginginnovatdistrictfurtherchangecoursetowardsalowtonet-zerocarbonengeneralrecommendationstoWuzhongonaddressingchallengesinth2.1ModelModelbuiltforWuzhongDistrictAlong-termenergysystemmodeloftheWuzhongDistrictwasbuiltucarbonemissionplanningpathwaysunderdifferentscenarios.Theminsightsintolong-termtechnologycapacityinvestmentanddispatchundercostandcarbonminimisationobjectives.Thecostandcarbonminimisationobjectivesarespecifiedasfollows:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁=�(1+𝑑𝑑𝑑𝑑)𝑌𝑌𝑌𝑌−𝑖𝑖𝑖𝑖∗𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇=�𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦where:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁isthenetpresentvalueofthetotalcost𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇isthetotalemissions𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦isthesetofmodellingyears𝑌𝑌𝑌𝑌isthestartingyear𝑑𝑑𝑑𝑑istheannualdiscountrate𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖isthetotalsystemcostinyear𝑖𝑖𝑖𝑖𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖isthetotalemissionsinyear𝑖𝑖𝑖𝑖.Theobjectivefunction(totalcostand/orcarbon)isminimisedsubjespecifiedtoincludeboundsontechnologycapacities,operationaisthetotalsystemcostinyear2.MethodologyThisstudytakesatwo-stepapproachtoaddressthechallengesthatWtransitiontowardsanet-zerocarbonfuture.ThefirststepistoexplohaveifthedistrictusedconventionalemissionabatementtechnologieconsideringWuzhong’slimitedpotentialforlocalrenewableenedominantfossilfuelconsumption.Along-termoptimisationenerconstructmultipleplanningscenarios.Thescenarioresultsshowhowgenerationfleetcanbereducedasmuchaspossiblethroughcoefficiencyimprovements,fuelswitching,andmodestincreasesinthresources.Thiswillhelplocaldecisionmakersunderstandthelimiapproachandwhytransformativemeasuresmightbeneeded.Thesecondstepfocusesondiscussionofasuiteofemerginginnovatdistrictfurtherchangecoursetowardsalowtonet-zerocarbonengeneralrecommendationstoWuzhongonaddressingchallengesinth2.1ModelModelbuiltforWuzhongDistrictAlong-termenergysystemmodeloftheWuzhongDistrictwasbuiltucarbonemissionplanningpathwaysunderdifferentscenarios.Theminsightsintolong-termtechnologycapacityinvestmentanddispatchundercostandcarbonminimisationobjectives.Thecostandcarbonminimisationobjectivesarespecifiedasfollows:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁=�(1+𝑑𝑑𝑑𝑑)𝑌𝑌𝑌𝑌−𝑖𝑖𝑖𝑖∗𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇=�𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖∈𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦where:𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁𝑁isthenetpresentvalueofthetotalcost𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇isthetotalemissions𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦isthesetofmodellingyears𝑌𝑌𝑌𝑌isthestartingyear𝑑𝑑𝑑𝑑istheannualdiscountrate𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖isthetotalsystemcostinyear𝑖𝑖𝑖𝑖𝑇𝑇𝑇𝑇𝑖𝑖𝑖𝑖isthetotalemissionsinyear𝑖𝑖𝑖𝑖.Theobjectivefunction(totalcostand/orcarbon)isminimisedsubjespecifiedtoincludeboundsontechnologycapacities,operationaisthetotalemissionsinyear16Theobjectivefunction(totalcostand/orcarbon)isminimisedsubjecttoconstraints,whichcanbespecifiedtoincludeboundsontechnologycapacities,operationandcapacityfactors,aswellasresourcepotential.Balancedconstraintsensurethatenergydemandsaresatisfiedbyinstalledtechnologycapacitiesineachtimeperiodandtimeslice.StructuralscopeThestructuralscopeofthebuiltmodelissummarisedinTable1.TABLE1:ModelstructuralscopeASPECTDETAILSSectors•Industrial•Services/commercial•Residential•TransportationEnd-useenergydemand•Electricity•Heat(process,space,hotwater)•Spacecooling•TransportEnergyimports(externaltothemodel)•Electricity(regional/nationalgrid,bysector)•Naturalgas(bysector)•Coal•Oil(transport)Localenergyresources•Biomass(waste)•SolarModellinghorizon2020-2050Intra-annualtimeperiod3yearsInter-annualtimeslice24-hourperiodsforthreerepresentativeseasonaldays(summer,winter,intermediate)OptimisationgoalCostorCO2emissionminimisationTechnologyscopeThescopeofenergyconversiontechnologiesunderconsiderationisdescribedinTable2byoutputorfunctionalcategory.Thesetechnologiesincludetheexistingandfutureinvestmenttechnologyoptionsinthemodel.Detaileddescriptionsofthesetechnologycategoriesandtheiradvantages,disadvantagesandkeyparametersarewelldocumentedbytheInternationalEnergyAgency’sETSAPprogramme(IEA-ETSAP,2014).NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA17TABLE2:ModelenergyconversiontechnologyoptionsandassociatedoutputsorfunctionsTECHNOLOGYELECTRICITYDISTRICTANDPROCESSHEAT(IND.)SPACEHEAT(SER./RES.)SPACECOOLING(SER./RES.)HOTWATER(SER./RES.)H2CCSSTORAGETRANSPORTATIONDISTRICTNETWORKCentralisedtechnologiesCoalCHPXXCoalboilersXCoalIGCCCCSXXGasCCPXGasCCPCCSXXGasCHPXXRegionalelectricitygridimportXWasteCHPXXWasteCHPCCSXXXWasteCCPXXWasteboilerplantXWasteincinerationplantXElectrolyserXBiomassgasificationXHydrogen(H2)storageXDecentralisedtechnologiesPVXSmallgasCHP(ind.)XXSmallfuelcellCHP(ind.)XXElectricspaceheater(ser./res.)XElectricwaterheater(ser./res.)XElectricboiler(ser./res.)XXGasboiler(ser./res.)XXGaswaterheater(ser./res.)XGasboiler(ind.)XWasteboiler(ind.)XAirconditioner(ser./res.)XAir-sourceheatpump(ser./res.)XX18TECHNOLOGYELECTRICITYDISTRICTANDPROCESSHEAT(IND.)SPACEHEAT(SER./RES.)SPACECOOLING(SER./RES.)HOTWATER(SER./RES.)H2CCSSTORAGETRANSPORTATIONDISTRICTNETWORKCentralair-sourceheatpump(ser./res.)XXXGround-orwater-sourceheatpump(ser.)XXCentralground-orwater-sourceheatpump(ser.)XXXSolarthermal(ser./res.)XXBatteriesXHeatstorageXInternalcombustionenginevehicleXBattery-electricvehicleXFuelcellvehicleXNetworksElectricitydistributionnetwork(losses)XDistrictheatingnetwork(losses)XCCP=combinedcyclepowerplant;CCS=carboncaptureandstorage;CHP=combinedheatandpowerplant;ind.=industrial;IGCC=integratedgasificationcombinedcycle;PV=photovoltaic;res.=residential;ser.=services.ReferenceenergysystemdiagramThemodelstructure,includingenergyimports,conversiontechnologies,end-useenergydemands,andthetransformationpathwaysthatconnectthem,isdepictedinFigure2.2.2Dataconstraints,estimationandassumptionsAswithmanycountries,theavailabilityandaccessibilityofenergydatainChinacanbeagreaterchallengeatthedistrictlevelthanatthenationalorprovinciallevels.Thisisinpartduetothelackofsoundenergystatisticssystemsforurbanenergysystemplanning,whichis–albeitrisingworldwide–stillrelativelynovelforlocalauthorities,particularlyintheChineseenergygovernanceregime.Thechallengesareoftenattributedtotheneedforhigherdatagranularitywithincitiesforenergyanalysisandplanning.Suchhighlygranulardataarehardtoacquireforvariousreasons(e.g.privacyissues).Inaddition,whenthesharesofvariablerenewableenergysourcesincreaseintheenergymix,theneedformoredetaileddataonboththesupplyanddemandsidebecomesgreater.NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA19FIGURE2:ModelreferenceenergysystemdiagramH2PVELHTCO_ImpNG_INDDEM_HT_SERDEM_HT_INDNG_SERDEM_HT_RESNG_RESWST_ImpElec.dist.network–Ser.DIST_SERElec.dist.network–Ind.DIST_INDDEM_CL_SERDEM_CL_RESEL_SEREL_INDEL_RESCoalJiangyuanplant-CHP/boilerCHP_CO/BLRP_COWasteplant(existing)ELCP_WSTBiomassboiler–Ind.BLR_WST_INDDEM_HTW_SERDEM_HTW_RESEL_IMP_INDEL_IMP_RESEL_IMP_SERNGBoiler–Ind.NG_BLR_INDDEM_EL_INDDEM_EL_SERDEM_EL_RESGascombinedcycleplant(CCP)(optional:+CCS)GCCP(+CCS)GasCHPCHP_NGSmallgasCHPCHPs_NGWasteCHP(optional:+CCS)CHP_WST(+CCS)BiomassboilerBLRP_WSTH2fuelcell-Ind.CHP_FCCentralHP(air,ground/water–Res.CHPA/GW_RESNGBoiler–Ser.NG_BLR_SERNGBoiler–Res.NG_BLR_RESNGwaterheater–Ser.NG_HTW_SERNGwaterheater–Res.NG_HTW_RESElec.boiler–Ser.EL_BLR_SERElec.boiler–Res.EL_BLR_RESElec.waterheater–Ser.EL_HTW_SERSolarthermal–Ser.ST_SERSolarthermal–Res.ST_RESElectrolyzerELH2EnergycarrierabbreviationsCL–coolingCO–coalDEM–demandEL–electricityH2–hydrogenHT–heatHTW–hotwaterIMP–ImportIND–industrialsectorNG–naturalgasRES–residentialsectorSER–servicesectorTR–transportationWST–wasteBio.gasiﬁcationH2_BGOIL_ImpDEM_TRElectricvehicleEVInternalcombustionenginevehicleICEVFuelcellvehicleFCVBiomassgasiﬁcationCCPBGCCPCoalIGCC+CCSIGCC_CCSHeatpump(air,ground/water)–Ser.HPA/GW_SERElec.dist.network–Res.DIST_RESCentralHP(air,ground/water)–Ser.CHPA/GW_SERWasteWST_ImpTCoalCO_ImpTNaturalgas–Ind.NG_ImpT_INDNaturalgas–Ser.NG_ImpT_SERNaturalgas–Res.NG_ImpT_RESDist.heatingnetwork–Ind.DH_INDHeatimportHT_ImpT_INDOil(transport)OIL_ImpTGridelectricityimport–Ser.EL_ImpT_SERGridelectricityimport–Res.EL_ImpT_RESGridelectricityimport–Ind.EL_ImpT_INDElec.heater–Res.EL_HTR_RESElec.heater–Ser.EL_HTR_SERHeatpump(air,ground/water)–Res.HPA/GW_RESACunit–Ser.AC_SERACunit–Res.AC_RESElec.waterheater–Res.EL_HTW_RESElec.devices–Ind.EL-CONV-INDElec.devices–Ser.EL-CONV-SERElec.devices–Res.EL-CONV-RES20Tofillgapsindatacollectionforthisstudy,proxydata,historicaltrendsandotherpubliclyavailableandpublisheddatawereadaptedtofitWuzhong’sprofile.Thesedatahavebeencalibratedwithsuppliedreferencedata.Assumptionswerealsomadeonthebasisoftheexpertknowledgeandinsightsobtainedforthisstudy,particularlyforprojectingfuturedemands.Themethods,assumptionsandresultingdatainputsappliedinthemodelaredetailedinthefollowingsections.CreationofhourlydemandprofilesThetotalhourlyloadprofileforthedistrictwasprovidedbytheStateGridCityandEnergyResearchInstitute(SGCERI).Thedataweredisaggregatedbysectorandend-usedemandtype.Thefollowingsubsectionssummarisetheapproachandthekeyresults.ElectricitydemandforindustrialsectorThehourlyindustrialloadprofilewascreatedfromhourlydatafortheindustrialsectorofadistrictwhoseindustrialstructureissimilartothatofWuzhong.2Thedataindicateabaseloadconsumptionpattern.Weadoptedthishourlybaseloadprofileasareasonableapproximationforourmodel.Figure3indicatesabaseloadconsumptionpattern,providingareasonableapproximationforthemodel.ElectricitydemandforserviceandresidentialsectorsThetotalelectricityloadprofilefortheserviceandresidentialsectorsisderivedfromthetotalelectricityloadprofilein2017minusthehourlyindustryelectricityload,followedbyfurtherdisaggregationbasedontheresidentialandserviceloadprofiles.Theresultingprofilesareadjustedtomatchavailableannualtotalelectricityconsumptiondata.Figure4representsthehourlyelectricitydemandprofilefortheservicesector;Figure5showstheprofilefortheresidentialsector.2.DatawereprovidedbySGCERI.FIGURE3:Hourlyelectricitydemandprofile–industrialsectorSummerIntermediateWinter0100200300400500600700800Load(MW)01234567891011121314151617181920212223HourNETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA21ProcessheatingdemandforindustrialsectorTheindustrialprocessheatloadprofilesweregeneratedbyapplyingtheratiosofprocessheatingloadamongthedifferentseasonstotheseasonalsharesoftheindustryelectricityloadshowninFigure3.Thehourlyloadcurve(Figure6)representsatypicaldayofoperationforaregionalheatingsysteminindustry(Lietal.,2018).Thisiscalibratedwiththetotalprocessheatingdemand.FIGURE4:Hourlyelectricitydemandprofile–servicesector050100150200250300350400450123456789101112131415161718192021222324SummerIntermediateWinterLoad(MW)HourFIGURE5:Hourlyelectricitydemandprofile–residentialsector050100150200250300350400450123456789101112131415161718192021222324SummerIntermediateWinterLoad(MW)HourFIGURE6:Processheatingdemandprofile–industrialsectorSummerIntermediateWinterLoad(MW)01234567891011121314151617181920212223Hour05010015020025030022SpaceheatingandcoolingdemandforserviceandresidentialsectorsSpaceheatingandcoolingisonlyconsideredfortheserviceandresidentialsectors,sincethesedemandsnotcomparabletoindustry.SinceWuzhong(locatedinanareawhereheatingsystemsarenotrequiredinChina)hasamildwinterseason,thespaceheatingdemandissmallcomparedwithnorthernareasinChina.ThedistrictheatinginWuzhongismainlyusedbyindustrialend-users,whileforserviceandresidentialsectorconsumers,weassumethatspaceheatingisentirelymetbyelectricityinthebaseyear;thisisalsoassumedforspacecooling(ChinaPower,2019).Moreover,weapproximatethatspaceheatingandcoolingisusedin,respectively,winterandsummerseasonsonly(basedondominantseasonalusage).ThehourlyloadprofileforcoolingisbasedonproxydatafromNanjing,anearbycity(Jiang,2003).Thedataarecalibratedtomatchthetotalseasonalelectricityloadprofile.TheresultingdemandprofilesforspaceheatingandcoolingineachsectoraregiveninFigures7-10.FIGURE7:Spaceheatingdemandprofile–servicesectorLoad(MW)01234567891011121314151617181920212223Hour050100150200250FIGURE8:Spaceheatingdemandprofile–residentialsectorLoad(MW)01234567891011121314151617181920212223Hour050100150200250300NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA23FIGURE9:Spacecoolingdemandprofile–servicesectorLoad(MW)01234567891011121314151617181920212223Hour0100200300400500600700FIGURE10:Spacecoolingdemandprofile–residentialsectorLoad(MW)01234567891011121314151617181920212223Hour050100150200250300350400450500HotwaterdemandforserviceandresidentialsectorsHotwaterdemandisconsideredonlyfortheserviceandresidentialsectors.TotalhotwaterdemandisapproximatedusingaverageparametersandthepopulationinWuzhong,summarisedinTable3(Zhang,ChenandLiang,2006).TABLE3:ParametersappliedtocalculateannualresidentialhotwaterdemandPARAMETERVALUELocalhotwatersupplysystem(L/person·day)40Specificheatcapacityofwater(J/kg·°C)4187Daysinyear2017365PopulationofWuzhongin2017(millionpeople)1.1295Densityofwater(kg/L)1Averagetemperatureofrunningwater(°C)15Averagetemperatureofhotwater(°C)40Source:Zhang,ChenandLiang,2006.24Hourlyhotwaterloadprofilesarebasedonhotwaterprofilesforresidentialandserviceorcommercialbuildings(Fuentes,ArceandSalom,2018).Thesecurvesareadjustedtomatchthetotalhotwaterdemand.TheresultingprofilesintheserviceandresidentialsectorsareshowninFigures11and12,respectively.DemandprojectionsEnergydemandispredictedoverthemodellingtimehorizonuntil2050.TheexponentialsmoothingmethodisusedtoprojectdatausingSPSSStatisticssoftware(Brown,1956;IBM,n.d.;Liu,2012).Demandprojectionsandassumptionsarepresentedinthefollowingsectionsbyenergycarriertype.FIGURE11:Hotwaterdemandprofile–servicesectorSummerIntermediateWinterLoad(MW)01234567891011121314151617181920212223Hour01020304050607080FIGURE12:Hotwaterdemandprofile–residentialsectorSummerIntermediateWinterLoad(MW)01234567891011121314151617181920212223Hour01020304050607080NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA25ElectricityforindustryandservicesectorsIndustryandserviceelectricitydemandprojectionsarebasedonhistoricalGDPgrowthtrends(asshowninFigure13)andpredicteddemandsin2025providedbySGCERI.Datafromtheyears2017-2025areusedtoprojectdemanduntil2050usingtheexponentialsmoothingmodelinSPSS.ThisapproachassumesGDPfollowsaroughlylogarithmicgrowthtrendinthefuture,inaccordancewithhistoricaltrends.ElectricityforresidentialsectorResidentialelectricitydemandisassumedtoincreasewiththepopulationgrowthinWuzhong.ThepopulationgrowthisbasedonanationalhighpopulationgrowthprojectionbytheUnitedNations,presentedinFigure14(Liang,2019).AhighgrowthtrendisassumedusinginputsfromSGCERI,whichindicatethatWuzhongexpectshigherthannationalaveragepopulationgrowthasitisarapidlydevelopingdistrict.FIGURE13:GDPgrowthinWuzhongDistrict,2013-2017Source:SGCERI,2019.ServiceIndustryAgriculture,ForestryandFishing100millionCNYYear20132014201520162017020040060080010001200FIGURE14:NationalChinesepopulationscenariosSource:basedonUNdata(UNDESA,2019).PredictionwithhighgrowthratePredictionwithlowgrowthratePredictionwithmediumgrowthratebyUNPredictionwithhighgrowthratebyUNPredictionwithlowgrowthratebyUN100millionYear201520202025203020352040204520501011121314151626TheresultingpopulationgrowthtrendfortheWuzhongDistrictisgiveninFigure15.TheresultingelectricitydemandpredictionsacrosssectorsarepresentedinFigure16.ProcessheatingforindustrialsectorIndustrialprocessheatdemandisassumedtoincreasewithindustrialelectricitydemandgrowth,asweassumethattheincreaseinelectricitydemandisreflectiveofgrowthinthissector,ingeneral.TheresultingprojectionisshowninFigure17.FIGURE15:PopulationgrowthfortheWuzhongDistrictPopulation(millions)Year202020232026202920322035203820412044204720501.101.121.141.161.181.201.221.241.26FIGURE16:ElectricitydemandprojectionsacrosssectorsDemand(GWh)Year2020202320262029203220352038204120442047205002000400060008000100001200014000160001800020000IndustryelectricityServiceelectricityResidentialelectricityTotalelectricityNETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA27SpaceheatingandcoolingforserviceandresidentialsectorsSpaceheatingandcoolingdemandisassumedtoincreasewithbuildingareagrowth.Buildingareaisprojectedusinghistoricalbuildingareagrowthdataandbyapplyingalogarithmiccurvefit(basedonhistoricaltrends).TheresultingbuildingareagrowthtrendisshowninFigure18.ProjectionsinspaceheatingandcoolingdemandsareshowninFigures19and20.FIGURE17:Processheatdemandprojection–industrialsectorDemand(GWh)Year2020202320262029203220352038204120442047205020002200240026002800300032003400FIGURE18:BuildingareagrowthforWuzhongDistrictArea(10000m)Year20202023202620292032203520382041204420472050700750800850900950100010501100115028HotwaterforserviceandresidentialsectorsHotwaterdemandisprojectedonthebasisofthepopulationgrowthinWuzhong(seeFigure15),asweassumehotwaterdemandgenerallyscalespercapita.TheresultingprojectionsareshowninFigure21.AggregatedprojecteddemandforallenergyservicesThetotaldemandprojectionforallenergyservicesintheWuzhongDistrictisillustratedinFigure22.FIGURE19:Spaceheatingdemandprojections–serviceandresidentialsectorsDemand(GWh)Year20202023202620292032203520382041204420472050ServicespaceheatingResidentialspaceheating200250300350400450500FIGURE20:Spacecoolingdemandprojections–serviceandresidentialsectorsDemand(GWh)Year20202023202620292032203520382041204420472050ServicespacecoolingResidentialspacecooling60070080090010001100120013001400NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA29AssumptionsmadeontechnologyspecificationsinthemodelThekeytechnologyspecificationsandassumptionsaredescribedinthefollowingsubsections.SolarenergyresourcepotentialEstimationsofsolarirradianceprofilesarebasedonafive-yearaverage(2015-2019)inWuzhong(Solcast,n.d.).NormalisedseasonalsolarprofilesaregiveninFigure23.SGCERIestimatesthatapproximately1860megawatts(MW)ofPVpotentialisavailableforWuzhonginthemediumterm.Atotalpotentialof2000MWisassumeduntil2050inthemodel.Forsolarthermalenergyapplications,giventheavailablelandareaforcentralisedinstallations,thesolarthermalpotentialisestimatedtobe975MW.FIGURE21:Hotwaterdemandprojections–serviceandresidentialsectorsDemand(GWh)Year20202023202620292032203520382041204420472050ServicehotwaterResidentialhotwater200210220230240250260270280290300FIGURE22:TotaldemandforallenergyservicesintheWuzhongDistrictDemand(GWh)Year2020202320262029203220352038204120442047205010000120001400016000180002000022000240002600030BiomassBiomassissourcedprimarilyfrommunicipalwasteinWuzhong.Therefore,weassumethatthetotalwastepotentialscaleswithpopulationgrowthingeneral.TheresultingbiomasswastepotentialisshowninFigure24.TransportationThreetransportationmodesareconsidered:internalcombustionenginevehicles,battery-electricvehiclesandfuelcellvehicles.Vehiclecostsanddrivetrainenergyconsumptionratesareconsideredforbattery-electricandfuelcellvehiclesrelativetointernalcombustionenginevehicles,basedonperformancedatafromYazdanieetal.(2016).EfficiencymeasuresBuildingefficiencystandardsareconsideredfornewbuildingsinWuzhongaccordingtonationalgreenenergybuildingstandards(CodeofChina,2019).Energysavingsareexpectedtobeintherangeof20-30%and30-40%fortwo-andthree-starbuildings,respectively,comparedwithFIGURE23:NormalisedseasonalsolarirradianceprofilesNormalisedirradiance01234567891011121314151617181920212223HourSummerIntermediateWinter00.20.40.60.81.01.2FIGURE24:BiomasswastepotentialprojectionPotential(GWh)Year202020232026202920322035203820412044204720503000310032003300340035003600NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA31non-energyefficientbuildings.Thecorrespondingincrementalcostsfornewtwo-starbuildingsare87.3CNYpersquaremetre(m2)(13.6USD/m2)and70.9CNY/m2(11.11USD/m2)forpublicandresidentialbuildings,respectively.Analogously,incrementalcostsforthree-starbuildingsare216.4CNY/m2(33.91USD/m2)and131.8CNY/m2(20.65USD/m2)forpublicandresidentialbuildings,respectively(Chai,2018).Efficiencyimprovementsarealsoconsideredforelectricalappliancesbasedonprojectedimprovementsuntil2050inEuropeanstudies(Kirchneretal.,2012).Improvementsinlighting,refrigeration,washer-dryers,TVsandotherappliancesareappliedtoChineseelectricityusagestatisticstodeterminenetefficiencyimprovementsovertime(Guo,KhannaandZheng,2016).Theresultingefficiencyimprovementratesrelativeto2020overtimeareillustratedinFigure25forresidential,serviceandindustrialsectorsforaverageandhighefficiencycases.Serviceandindustrialsectorimprovementsappearrelativelylimitedbecauseonlylightingefficiencygainsareconsideredinthesesectors(duetolimiteddataavailabilityforotherend-useconverters).ThermalandgasnetworksThedistrictheatingnetworkinWuzhongprimarilyservesindustryandis,therefore,consideredfortheindustrialsectoronly.Heatimportsfromthesurroundingareasareconsideredonlyinthebaseyear.Dataonmaximumannualnaturalgasimportsbasedonexistingandfutureinfrastructurewerenotavailable.Therefore,themodelimposesanupperlimitof10terawatthours(or36petajoules)ofgasimportsinthebaseyear;thislimitscaleswithincreasingtotalenergydemanduntil2050.CarboncaptureandstorageThreepowerplanttechnologieswithcarboncaptureandstorage(CCS)capabilitiesareconsideredinthenet-zeroemissionsscenario:wastecombinedheatandpowerplant(CHP),gascombinedcyclepowerplant(CCP),andcoalintegratedgasificationcombinedcycle(IGCC)powerplant.ItisassumedthatcarbonstorageispossibleeitherthroughtheconstructionofageologicalstoragefacilitylocallyorthroughtransporttoasubterraneanstoragefacilityoutsideofSuzhoucity.FIGURE25:RelativeefficiencyimprovementsforelectricalappliancesacrosssectorsRelativeeciencyimprovementResidentialServiceIndustryYear100%120%140%160%180%200%220%20152020202520302035204020452050205532WemodelthewasteCHPCCSafterabio-energyCCSdemonstrationplantinOslo,Norway(Klemetsrudwaste-to-energyplant,operatedbyFortumOsloVarme).Therearecurrentlyonlyahandfulofsuchoperationalplantsintheworld;thisplantwasselectedasabasisformodellingbecauseitisoneofthenewestandmostadvanceddemonstrationprojectsofthistypeforwhichdataareavailable.TheCHPincineratesmunicipalandindustrialresidualwastefrombothnationalandinternationalcustomers.Itconsistsofthreeincinerationlinesthatproducefluegas,fromwhichCO2iscapturedusinganabsorptiontechnologywithanAkerSolutionAdvancedAminesolvent.Itisalsoequippedwithtwosteamturbines.Theplantaimstocaptureapproximately200000tonnesofCO2eachyear.CapturedCO2istransportedtoanonshorefacilityonNorway’swestcoastfortemporarystorage,followedbypipelinetransporttoasubseareservoirintheNorthSeaforpermanentstorage(Fortum,n.d.;ProjectCCS,2019).TheIGCCCCSplantusesathermo-chemicalreactionwithoxygenandsteamtoconvertcoalintoagasmixtureofmainlycarbonmonoxide,hydrogenandCO2.Thismixtureiscleaned,andpre-combustionCO2captureisusuallyperformedusingphysicalsolvents.Thecleanedgasmixisthenusedingasandsteamturbinesforelectricitygenerationinacombinedcycle.IngasCCPCCS,post-combustionCO2captureisusuallyundertakenusingsolvents.CapturedCO2canbestoredlocallyortransportedforstorageelsewhere.EmissiondataEmissionsareassumedforthecombustionoffossilfuels(i.e.coal,naturalgasandoil)basedonstandardcombustionemissiondata;namely,thecarboncontentperunitofenergythefuelcontainsforcombustion.Thesedatadonottakeintoaccounttheheatlossthatoccursduringthecombustionoffossilfuelsforelectricitygeneration(EngineeringToolBox,2009).Todemonstratethedifferenceamongdifferentfossilfuelsintermsofcarboncontent,combustionemissionvaluesof0.28kilogrammes(kg)ofCO2perkilowatthour(kWh),0.18kg-CO2/kWhand0.26kg-CO2/kWhareassumedforcoal,naturalgasandgasoline,respectively.ElectricityimportedtoWuzhongfromtheregionalgridisprojectedonthebasisoflong-termregionalelectricityplanning.Weassume50%oftheelectricitygenerationmixin2050isemissions-free(comparedtoa20%shareinJiangsuprovincein2020).TheresultingemissionfactorprojectionisillustratedinFigure26.FIGURE26:CarbonemissionfactorforgridelectricityGridemissionsfactor(t-CO/GWhel)Year20202023202620292032203520382041204420472050400450500550600650700750800NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA332.3LimitationsThemodelinthisstudyaimstoprovideamacro-level,long-termanalysisfortheWuzhongDistrictusingalinear,cost3andcarbonoptimisationmodel.ItprovidesastrongbasisfordevelopingasustainableenergystrategyforWuzhongaspartofaniterativedesignprocess.Additionalinputswouldenablefurtherrefinementandexpansionofthecurrentmodelandscenarios,whichwouldthenserveasinputsforrefiningtheenergystrategy.Thelimitationscanbesummarisedasfollows:•Theobservedoutcomesinalinearoptimisationmodelaredictatedbydataassumptionsandassumedboundaryconditions.Improveddatainputsandassumptionswillyieldmoreaccurateresults.Additionaldataparametersthatwouldimproveanalysisincludefuturecostestimatesforenergycarriersanddetailedinfrastructuredataforpowergridanddistrictenergynetworks(e.g.capacities,expansionpotential,costs),asthecurrentmodeldoesnotconsiderinfrastructuredetails,limitationsandexpansions.Shouldnetworkdatabecomeavailable,ahigherresolutionmodelcouldbedevelopedaspartofafuturestudytoinvestigatetheoptimaldesignandimplementationofthesenetworks.•Withfurtherdistrictheatingdataandmodelling,thescopeoftechnologyoptionscouldalsobeexpanded.Forinstance,theroleofsolarthermalandheatstorageatadistrictlevelforlow-temperatureheatingcouldbeadded(inthecurrentmodel,heatstorageisonlyconsideredatadecentralisedlevel).ShouldthemaximumPVpotentialbeexpandedorotherintermittentrenewableenergytechnologiesprovefeasible,batterytechnologiesmayalsocometoplayanimportantroleinWuzhong,asstoragewouldimprovedemand-sideflexibility.•Furtherdataonthetransportationsectorandinfrastructurewouldalsoallowforthedevelopmentofamoredetailedtransportmodel.Thisopensupopportunitiesforsectorcouplingbetweentransportationandelectricitydemand,forexamplebyconsideringbattery-electricvehiclesasapotentialstoragesource(i.e.operatingasavirtualpowerplant,whichalsoincreasesdemand-sideflexibility)orconsideringgas-to-poweropportunitiesforfuelcellvehiclesshouldregionallow-carbonhydrogenorsyngasgenerationbecomeavailableinthefuture.•TheadditionofdataregardingthepotentialofefficiencymeasuresintheWuzhongDistrictisanotherareaforexpansion.AsefficiencymeasuresdemonstratesignificantpotentialtoreducelocalenergydemandandcarbonemissionsinWuzhong,furtherstudiesareneededtoidentifyareasforefficiencyimprovement,energysavingpotential,andimplementationcosts.Thisisespeciallyapplicabletotheindustrialsectorandexistingbuildingstockrenovations,wherefeasible.•LimiteddataonCCSapplicabilityinWuzhongareavailable.Furtherstudyonitsfeasibilitywouldbenecessarytojustifyitasafeasibleoptionforthedistrict.3.ThecostdataappliedinthisstudycanbefoundinAnnexC.34©EvgenyBakhchev/shutterstock.com3NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA35MODELLINGSCENARIOSANDRESULTSThischapterpresentsthefourscenariosthatwereconstructedforthestudy:abaselinecase(BC)scenarioforcomparativepurposesandthreelow-carbonscenarios.Themaindifferencesbetweenthescenarioslieinemissionreductiontargetsandtechnologyscope.3.1BaselinecaseTheBCrepresentsascenariowithoutanemissionorrenewableenergydevelopmenttarget.Therefore,theoptimisationintheBCusesonlyonemodellingobjective:minimisingthetotalsystemcosttomeetthegivenenergydemand.Itincludesallthegenerationtechnologyoptionsinthetechnologyscopewhenperformingtheoptimisation,exceptforCCS.Thekeycurrentdecisiononfuelswitching,whichessentiallyaimstophaseoutcoalpowerinthedistrict,hasalsobeenfactoredin.Ontheenergyefficiencyside,theBCscenarioadoptsaverageimprovementmeasures,whichareassumedtomeetthetwo-stargreenbuildingstandardfornewresidentialbuildingsandthethree-starstandardforcommercialandservicebuildings.Inthetransportsector,giventheoverallrapidpaceofvehicleelectrificationinChina,thisscenarioassumes20%and50%ofthetransportationfleetinWuzhongDistrictiselectrifiedby2035and2050,respectively.TheaimfordevelopingsuchaBCistoprovideabenchmarkforcomparisonofmodellingresults,particularlyofthepotentialimpactofcarbonconstraintsandtargetsonthegenerationprofileforthedistrict.Theonlycoal-firedpowerplantinWuzhongDistrictwillbereplacedbyanewgas-firedpowerplant,whichhasbeenalreadyindicatedbythelocalauthority.Thus,thedistrictwillbecoal-freefromasearlyas2022.Thisalsomakeseconomicsense,giventhattheplantissmall(30MWincapacity).Thisisthecut-offsizefortheclosureofinefficientcoalpowerplantsaspartofthenationalcleanenergypolicy.Smallcoalplantscanhardlycompeteeconomicallywithnationalgridelectricity.Phasingoutcoalpowercanalsoeliminatethelogisticalneedforcoaltransportationbywaterwayandrailway,aswellasstorage–anothersavingtobegainedtojustifytheclosureofthisplant.36Figure27illustratesthemodellingresultsfortheBCscenario.Asshown,electricityfromtheregionalandnationalgridswillbeexpectedtoincreasebyabout50%overtheprojectedperiod,providingthemostcost-effectiveelectricitytomeetgrowingelectricitydemandinWuzhong.Forthefirsthalfofthestudiedperiod,electricityfromthelocalgas-firedpowerplantsisexpectedtoscaleuptomeetthedemandgrowth,exceptfortheinitialtransitionphasefromcoaltogasinpowergenerationin2021-2022.Thisalsofitstheoverallnationalstrategytousenaturalgastoreplacecoalasatransitionalsteptowardsrenewables.Forthesecondhalfoftheprojectedperiod(i.e.2036-2050),renewableelectricitywillbeexpectedtotakeoffandreplacegasduetoitsstrongcostcompetitiveness.Therefore,thecombinedshareofgas-firedelectricityandrenewableelectricityoverthenextthreedecadeswouldmakeuptheremainingquarterofthesupplyforWuzhongintheBC.Intheareaofrenewables,solarPVwillgrowdramaticallytoover85%ofitsfullresourcepotential,evenintheBC,thankslargelytothecostdecline.Thismakesitaverycost-competitivesourceofelectricitygenerationatthelocallevel,indicatingassociatedbenefits,suchasthecreationoflocaleconomicactivitiesandjobopportunities.PVisprojectedtoprovide11%oftheelectricitysupplyby2050.Solarthermalenergyintheservicesectorwillalsogrow,butitscontributiontotheoverallrenewableportfoliowillberathermodest.Anothersizeablecontribution,asfarasrenewableapplicationsareconcerned,willbefromwaste-to-energysystems,accountingfornearly10%ofenergygeneration.Thisoptionaddressestwochallenges–wastemanagementandcleanenergygeneration–inonego.Nevertheless,apotentialbarriertothisoptionistheconstraintonlandavailabilityandlimitedoptionsforsiting.Therefore,carefulurbanplanningwouldbeofcriticalimportanceinthisregard.Inaddition,thewasteheatfromgas-firedCHPshasaroletoplayuntilatleast2035,whenthelowercostofimportedelectricity,renewableelectricityanddecentralisedheatgenerationwillgraduallyreplacegas-basedoperation(althoughthefacilitiesmightbekeptforemergenciesandforregulatingpowergeneration).Overall,by2035and2050,thesharesofrenewableswouldreach13%and21%,respectively,intheBC.FIGURE27:Baselinescenario–electricityandheatproductionAC=airconditioner;CCP=combinedcyclepowerplant;CCS=carboncaptureandstorage;CHP=combinedheatandpowerplant;HPA=air-sourceheatpump;HPGW=ground-orwater-sourceheatpump.05101520253020202023202620292032203520382041204420472050Generation(TWh)Wasteplant(existing)WasteCHPCCSWasteCHPWasteCCPSolarthermImport-elecHPGWHPAGaswaterheaterGasCHPGasboilerElecwaterheaterElecspaceheaterCoalCHPCoalboilerplantACNETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA37Inthisscenario,theenergyperformancerequirementsforresidentialandcommercialbuildingsareimplementedattheminimumrequiredrateinthemodel.Yetwewouldseeariseintheuseofheatpumpsinresidentialandcommercialorservicebuildings.Heatpumpswilltakeoff,regardlessofemissionconstraints,thankstotheeconomicbenefitstheycanbringthroughimprovedefficiencyofenergyuseandthegrowingdemandtoregulateroomtemperatureforcomfortunderfutureclimatechangeconditions,whereextremeweatherpatternswouldoccurmorefrequentlyandmoreseverelythanbefore.ForWuzhong,bothindividualunitsandthecentralisedapplicationofheatpumpswouldbeadoptedsubjecttothedemanddensityinagivenareawithinWuzhong.3.2CarbonpolicyThecarbonpolicy(CP)scenariodescribesacaseinwhichtheWuzhongenergysystemisdrivenbyanobjectivetoreducecarbonemissionsby15%by2040comparedwith2020levels–atargetrecommendedincarbonpeakguidelinesforShanghaiandSuzhoubytheChineseNationalCenterforClimateChangeStrategyandInternationalCooperation(Caoetal.,2019).Thisscenarioisnotintendedtoachievenet-zeroemissionby2050butrathertopresentaportfolioofenergytechnologiesforachievinggradualemissionreductionsunderasuggestedCPwhilekeepingcostminimisationasanoptimisationobjective.Thisscenarioincludesimprovedenergyefficiencymeasuresforend-useappliancesandthree-starbuildingenergyperformancestandardsfornewresidentialandserviceorcommercialbuildings.Italsoincludesahightransportationelectrificationrateof40%by2035and70%by2050.Wuzhonghasalesscarbon-intensiveeconomicstructurethantheSuzhouaverageanddoesnothavemanycarbon-intensiveindustries,includingfossilfuel-basedenergygenerationfacilities,initsterritory.Therecommendedcarbontargetappliedintheanalysis(a15%reductionover2020-2040)isconsideredmodestandreasonableincomparisonwiththehistoricalandprojectedtrajectoriesofSuzhoucity’scarbonemissions:(a)over2006-2017,theannualgrowthrateofemissionshaddeclinedfrom+20%to-7%,whilethetotalemissionsbecamerelativelystable,intherangeof160milliontonnesCO2since2013,withaslightdownwardtrendin2017;(b)over2020-2050,theemissionswillbereducedby26%undertheprescribedpolicyobjectivetorealiseasmoothtrajectoryforemissionreductionsafterpeakingin2020(WRI,2020).AswiththeBCscenario,coal-firedpowergenerationhasnoroletoplayinthisscenarioafteritsphaseoutintheearly2020s.IntermsofgenerationfromsolarPVby2050,thedifferencebetweentheBCandCPscenariosisrathersmall,giventhelimitedtotalresourcepotentialavailableinWuzhong,asindicatedinFigure28.TheimportantadvancementintheCPscenarioisthatthesolarPVgenerationwillscaleupsignificantlyearlierthanintheBCscenarioandwillreachitsfullpotentialinabout2040.OnlymainstreamtechnologiessuchasrooftopPVaremodelled,whichsuggestspotentialroomforgrowthofsolarPVbyapplyingadvancedandinnovativetechnologiessuchasbuilding-integratedPV(BIPV)onbuildingenvelopesandothercity-integratedsolarsolutions(tobediscussedinthenextchapter).AsintheBCscenario,municipalandindustrialwaste-to-energyfacilities,aswellasheatpumps,continuetosupplythemajorityofheatdemandinWuzhong.Solarthermalenergyforbothresidentialandcommercialorservicebuildingswillalsomakeacontributiontomeetingtheheatdemand,butatascaleassmallasone-sixthofthatfromtheotherheatsources.38IntheCPscenario,importedelectricityfromthegridwillaccountforasignificantshareoftheelectricitymixinthesecondhalfoftheprojectedperiodinviewoftheoveralldecarbonisationofthegridelectricitymixinChina.Inthemediumterm,however,gas-firedpowerplantsthroughCCPandCHPwillhaveanimportantroletoplayinachievingtheCPobjective,undertheassumptionthatthecarbonintensityofgridelectricity4willnotdramaticallydeclineuntil2035,afterwhichlow-carbonenergygenerationisplannedtosignificantlyacceleratetowardsachievingnet-zerogoalsby2060.Overall,sincethecarbonemissiontargetissetrathermodestlyinthisscenario,thereisinsignificantdifferenceintermsofthegenerationprofilefromthatintheBC,exceptthattheroleofnaturalgasaltersaround2035,asdiscussedbefore.However,thelocalenvironmentalbenefitsfromcarbonemissionreductionsdrivenbytheCP,whichhavelongbeenrecognisedatbothinternationalandlocallevels(Karimetal.,2017;UNECE,2016),shouldnotbeoverlooked.AstudyontheShanghaiarea–amegacityadjacenttoSuzhoucity,whereWuzhongislocated–hasalsosuggestedthatshiftingfromcarbon-intensiveenergygenerationtechnologiestolow-carbonsolutionsoffersacost-effectivewaytoimprovethelocalenvironmentalquality(GielenandChen,2001).Therefore,itisimportantforWuzhong–adistrictwithamandatetopreserveitsecologicalandenvironmentalquality–togiveseriousconsiderationtosettingcarbonemissionreductiontargetsinitsenergypolicyandplans.4.Currently,coal-firedpowergenerationstillaccountsfornearly60%ofthenationaltotalelectricity;itsemissionfactorismuchhigherthanthatoftheelectricityfromgas-firedgenerators.FIGURE28:CPscenario–electricityandheatproductionCCP=combinedcyclepowerplant;CCS=carboncaptureandstorage;CHP=combinedheatandpowerplant;HPA=air-sourceheatpump;HPGW=ground-orwater-sourceheatpump;PV=photovolatic.05101520253020202023202620292032203520382041204420472050Generation(TWh)Wasteplant(existing)WasteCHPCCSWasteCHPWasteCCPSolarthermSolarPV+battImport-elecHPGWHPAGaswaterheaterGassCHPGasCHPGasCCPGasboilerElecwaterheaterElecspaceheaterCoalCHPCoalboilerplantACNETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA393.3SustainabledevelopmentscenariosThesustainabledevelopment(SD)scenariosexamineoptimalplanningpathwaysforarangeofCO2emissionreductionobjectivesoverthemodellinghorizon.Theobjectivesrangefromcost-optimalCO2emissionminimisationatoneendtocost-onlyminimisationattheother,withvaryingCO2targetcasesinbetween.AParetoefficiencycurveisdevelopedfortheSDscenariotodemonstratetheplausiblesolutionspaceforachievingthedualobjectives.First,wepresentascenarioforminimisingcarbonemissionswithoutCCS(theSD-CO2Minscenario),asillustratedinFigure29.Fornowandtheforeseeablefuture,electricityisexpectedtoremainthelargestshareofthefinalenergyconsumptioninWuzhong.Theoptimaloptionforminimisingemissionswillbemaximisingtheuseoflocalrenewablesandsubstitutinggridelectricitywithlocalgas-firedpowergeneration(Figure29).Forrenewables,themaximallevels,intermsofresourcepotentialandtheefficienciesofconversiontechnologies,willbereached.Forinstance,incontrastwiththeCPscenario,wasteisoptimallyusedtogeneratebothelectricityandheatusingCHPsinthelongterm(comparedwithheat-onlygenerationusingindustrialboilersintheCPscenario).Inthisscenario,theelectricityimportedfromthegridtoWuzhongwillbereducedbyapproximatelytwo-thirdscomparedwiththeBCandCPscenariosin2050.Thesupplygapwillbefilledbyasubstantialincreaseingas-firedpowergeneration,stretchingthenaturalgasimportpotentialtothelimit,andbya70%and40%increaseinrenewableelectricityincomparisontotheCPandBCscenarios,respectively.Othermeasures,particularlyscalinguptheuseofheatpumpscoupledwithrenewablethermalenergysourcesforresidentialandserviceend-users,willalsocontributetocarbonemissionminimisation.FIGURE29:SD-CO2Min–electricityandheatproductionAC=airconditioner;CCP=combinedcyclepowerplant;CCS=carboncaptureandstorage;CHP=combinedheatandpowerplant;HPA=air-sourceheatpump;HPGW=ground-orwater-sourceheatpump;PV=photovoltaic.05101520253020202023202620292032203520382041204420472050Generation(TWh)Wasteplant(existing)WasteCHPCCSWasteCHPWasteCCPSolarthermSolarPVImport-elecHPGWHPAGaswaterheaterGassCHPGasCHPGasCCPGasboilerElecwaterheaterElecspaceheaterCoalCHPCoalboilerplantAC40However,theplausibilityofthisscenariocaneasilybechallengedduelargelytoconstraintssuchasthelackofavailablelandforinstallingsuchalargenumberofgaspowerfleets,thegassupplyandvolatilityovertime,andthehighcostpertonneofCO2avoided.Nevertheless,theSD-CO2MinscenariodoessuggestthatthereisaneedfortheotherSDscenarios,withabalancedtrade-offbetweenemissionreductionsandcosts–twokeyelementstobeconsidered.ThegenerationmixfortheSD-CostMinscenario,illustratedinFigure30,presentsasuiteoftechnologyoptionstodeliveracost-optimalsolutionunderminimalCO2reductionconstraints.ItbearscloseresemblancetotheBCscenario(Figure27)withonly6milliontonneslessintotalCO2emissions,largelyduetostrongerefficiencymeasuresandalargerrenewableenergytargetsharethantheBC.TheCO2emissionsintheSD-CostMinscenarioarenearly40%higherthaninSD-CO2Min.SD-CO2Mid,presentedinFigure31,aimstobalancethetrade-offsbetweenelectricityimports(i.e.higherimportsforcostoptimality)andgastechnologies(i.e.highergasgenerationforlowCO2)tomeetamid-rangeCO2reductiontarget(halfwaybetweentheCO2emissionsleveloftheSD-CO2MinandSD-CostMinscenarios).Insomeways,thisscenarioappearssimilartotheCPscenario,exceptforaslightlygreateruseofgridelectricitytowards2050thanintheCPscenario,inviewofthecarbonandcosttargets.FIGURE30:SD-CostMin–electricityandheatproductionAC=airconditioner;CCP=combinedcyclepowerplant;CHP=combinedheatandpowerplant;HPA=air-sourceheatpump;HPGW=ground-orwater-sourceheatpump.05101520253020202023202620292032203520382041204420472050Generation(TWh)Wasteplant(existing)WasteCHPWasteCCPWasteboilerSolarthermSolarPVImport-elecHPGWHPAGaswaterheaterGasCHPGasboilerElecwaterheaterElecspaceheaterCoalCHPCoalboilerplantACNETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA41Figure32presentsthegenerationmixfortheSD-CO2Min-LDscenario,whichissimilartotheSD-CO2Minscenario,butwithreduced(highCO2)gridimportsundertheassumptionofgreaterenergyefficiencyimprovementsleadingtoreducedoveralldemand.FIGURE31:SD-CO2Mid–electricityandheatproductionAC=airconditioner;CCP=combinedcyclepowerplant;CHP=combinedheatandpowerplant;HPA=air-sourceheatpump;HPGW=ground-orwater-sourceheatpump;PV=photovoltaic.05101520253020202023202620292032203520382041204420472050Generation(TWh)Wasteplant(existing)WasteCHPWasteCCPWasteboilerSolarthermSolarPVImport-elecHPGWHPAGaswaterheaterGassCHPGasCHPGasCCPGasboilerElecwaterheaterElecspaceheaterCoalCHPCoalboilerplantACFIGURE32:SD-CO2Min-LD–electricityandheatproductionAC=airconditioner;CCP=combinedcyclepowerplant;CHP=combinedheatandpowerplant;HPA=air-sourceheatpump;HPGW=ground-orwater-sourceheatpump;PV=photovoltaic.05101520253020202023202620292032203520382041204420472050Generation(TWh)Wasteplant(existing)WasteCHPWasteCCPWasteboilerSolarthermSolarPVImport-elecHPGWHPAGaswaterheaterGassCHPGasCHPGasCCPGasboilerElecwaterheaterElecspaceheaterCoalCHPCoalboilerplantAC423.4Net-zeroCO2scenarioAhighlyhypotheticalscenarioaimedatachievingnearnet-zerocarbonemissionswithlocallyself-sufficientenergygenerationwasalsodeveloped;thisisknownasthenet-zeroCO2emissions(NZC)scenariointhisstudy.Despiteitbeingunlikelytooccur,giventheenergygovernanceandgreatdegreeofintegrationofphysicalpowersystemsatvariouslevelsthroughouttheentirecountry,itisinterestingtoexaminetheplausibleoptionsthatthecurrenttechnologiescouldprovideifemissionshadtobecuttonearnet-zerothroughlocalgenerationandresources.AsillustratedinFigure33,intheNZCscenario,themodellingresultsindicatethatCCStechnologieswouldhaveamajorroletoplayinmitigatingCO2emissions.AdistinctshiftisobservedfromgridimportstowardslocallygeneratedelectricityandcarboncaptureusinggasCCPsandcoalIGCCpowerplantsthatwouldhaveCCSinstallations.Gridimportsareentirelyreplacedonanetannualbasisbythesetechnologiesby2030,accompaniedbymaximaldeploymentofPV,waste-to-energy,ground-orwater-sourceheatpumps,andsolarthermaltechnologiesuntil2050(asobservedintheSD-CO2Minscenario).AlsoasintheSD-CO2Minscenario,gasimportsaremaximallyutilised,indicatingthatgasCCPCCSispreferred(i.e.ismorecost-effective)overcoalIGCCCCS.OncethegasCCPCCSisfullyutilised,IGCCCCSisinstalledtodecarbonisetheelectricitymix.GasCCPandwasteCHPfacilitieswouldbeequippedwithCCStoreducecarbonemissions,undertheassumptionthatsequestrationdoesnotpresentanissue,whichwillbediscussedfurtherinthenextchapter.FIGURE33:Net-zeroCO2emissionsscenario–electricityandheatproductionAC=airconditioner;CCP=combinedcyclepowerplant;CCS=carboncaptureandstorage;CHP=combinedheatandpowerplant;HPA=air-sourceheatpump;HPGW=ground-orwater-sourceheatpump;I=industrial;IGCC=integratedgasificationcombinedcycle;PV=photovoltaic.05101520253020202023202620292032203520382041204420472050Generation(TWh)Wasteplant(existing)WasteCHPCCSWasteCHPWasteCCPWasteboilerSolarthermSolarPVImport-elecHPGWHPAGaswaterheaterGassCHPGasCHPGasCCPCCSGasCCPGasboilerElecwaterheaterElecspaceheaterCoalIGCCCCSCoalCHPCoalboilerplantACNETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA433.5ParetoefficiencyCostsandnetCO2emissionsaresummarisedinFigure34acrossthevariousscenarios.AParetoefficiencycurveisalsoplottedfortheSDscenarios.Thiscurveillustratestheboundaryofcost-optimalsolutionsthatsatisfydifferenttotalCO2targets,fromtheCO2minimisationorientedscenario(SD-CO2Min)tothecostoptimisationscenariowithoutaCO2target(SD-CostMin).CarbondioxideemissionsfortheSD-CO2Min-LDscenario,whichhasa15%lowerenergydemandthanSD-CO2Min,andtheNZCscenarioarealsopresentedinthechartforcomparison.TheSD-CO2Minscenarioyieldsemissionsthatare28%lowerthantheSD-CostMinscenario,withtotalcoststhatare17%greater.TheCPscenarioliesalmostdirectlyontheParetofront,closetotheSD-CO2Midscenario;however,itliesclosertothecost-minimisedSD-CostMinscenariothanthecarbonminimisedSD-CO2Minscenario,indicatingthattheCPappearstobereasonablydesignedintermsofpracticalachievability,providingastrongbalancebetweencostandcarbonminimisationobjectives.Emissionreductionsduetotheshiftfromimportedgridelectricitytolocalgenerationusinggas-basedtechnologiesplayasignificantroleintheCPandSD-CO2Minscenarios,whichdemonstrateapproximately15%and30%lowernetCO2emissions,respectively,comparedwiththeBCscenario.EmissionsreductionintheSD-CostMinscenariocomparedwiththeBCscenarioisonlyabout5%,whichisalmostentirelyduetotheenergyefficiencyimprovementmeasuresconsideredinthemodel.Thisindicatesthatfurtherinvestigationisrequiredintomoreadvancedandinnovativedemand-sidetechnologies.TheSD-CO2Min-LDscenarioindicatesasimilartrend,wherebyemissionsare18%lowerforSD-CO2Min-LDthanforSD-CO2Min.Thisreductionisachievedthroughreducedenergydemand,whichisassumedtobeimplementedexogenouslythroughdemand-sidemanagement,belowaveragegrowthtrends,orothermeasuresresultinginreducedlong-termenergydemand.FIGURE34:CostsversusCO2emissionsacrossscenariosandParetoefficiencycurveBC=baselinecase;CP=carbonpolicy;NZC=net-zeroCO2emissions;SD=sustainabledevelopment.Totaldiscountedcost(USDBN)Totalemissions(Mt-CO)15.016.017.018.019.020.021.02535455565758595105115BCSD-LDSDParetoNZCCPSD-COMinSD-CostMinSD-COMid44TheNZCscenariopresentsaspecialcase,with70%loweremissionsthanSD-CO2Minforacomparative14%increaseintotalsystemcosts.However,asmentionedintheprevioussection,thisscenarioislesslikelytooccurandbearshighuncertaintiesintermsofCCStechnologyapplicabilityandtheassociatedcostsforthedistrict.However,giventhatCCSorcarboncapture,utilisationandstoragecanbeeffectiveapproachesundercertaincircumstances(Box2),thereisstillaneedformorediligenceonthisfrontforWuzhongtobetterunderstandtheviabilityofthisoptionfromalong-termperspective.Lastly,intheNZCscenario,forthetransportsectortheuseofoilwillbereplacedbyfullelectrificationofthesector.BOX2:Roleofcarboncapture(utilisation)andstorageCarboncaptureandstorage(CCS)orcarboncapture,utilisationandstorage(CCUS–whenutilisationofcapturedCO2isinvolvedaspartofthecarbonmanagementprocess)canbeaneffectiveapproachforaddressingcarbonemissionsfromtheuseoffossilfuelsintheabsenceoffeasibleabatementtechnologysolutions.Thistypicallyhappensinindustrialsectorswherefossilfuelscannotbesubstitutedwithouttechnologicalbreakthroughsasthespecificrequirementsfortheindustrialprocessescannotbemetbythecurrentoptions.Forinstance,inthecementindustry,processemissionsfromcementclinkerproductionformthemajorityofemissions,anditisdifficulttodecarbonisetheemissionsusingonlyrenewableenergysourcesduelargelytothehightemperaturerequirementsoftheprocess(IRENA,2020b).Onthisfront,Chinaproduced60%oftheworld’scementin2019(Wang,2021).Whileenergyintensitymeasuredbykilogrammescoalequivalentpertonne(kgce/tonne)ofcementinChinacanbeexpectedtoimprovebyatleast26%comparedwithinternationalbestpractices,thiswouldnotnecessarilytranslatetoemissionreductionssincereducedenergyinputsaremainlyfromalternativefuelsusingrecycledpetroleum-basedproductslikeplasticsandtires.Reducingemissionsfurtherwouldrequireend-of-pipetechnologiessuchasCCSorCCUSinsectorssuchascement,ironandsteeltoachievecarbonneutralitygoals.Asof2020,thereare40CCUSprojectsinChina,includingbothoperationalandunder-constructionfacilities,capturing3milliontonnesofCO2perannum.By2060,ChinaestimatesthatCCUScouldpotentiallyreducecarbonemissionsintherangeof0.6-2.1billiontonnes,subjecttotheneedtomeetthecarbonneutralitygoal,accordingtotheChinaCCUSAnnualReport:Roadmap2021(Cai,LiandZhang,X.,2021).However,mostcarbonstoragecapacitiesarelocatedinthenorth,eastandnorthwestofthecountry.ForthesouthernandcoastalregionsofChina,thestoragecapacitiesaremoderateduetopoorgeologicalconditionsasfarascarbonstorageisconcerned.ItiswidelyacknowledgedthatCCUSwillplayaroleinChina’sroadmaptowardscarbonneutralityby2060,despitetherebeingahighdegreeofuncertaintyforagivenlocation.Source:IRENA,2021;Lyons,DurrantandKochhar,2021.NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA454©Maple90/shutterstock.com446DISCUSSIONMovingtowardsnet-zeroemissionscanbeachievedforWuzhongDistrictthroughacombinationoflocalandregionalmeasuresifWuzhongstepsupitseffortsinthefollowinginterrelatedstrategicareas.Theseareaswillenableexpansionofthedecarbonisationoptionspresentedinthemodellingresults.ThischapterdiscussesasuiteofemerginginnovativesolutionsthatWuzhongshouldconsider,giventhelimitationsofconventionalabatementmeasures,aspresentedinthepreviouschapters.ThediscussioninthischapteralsohasstrongrelevancetoChinesecitiesanddistrictswithasimilarprofiletoWuzhongand,thus,canbeusedasastartingpointforthemtodiscusstheirpathwaystowardsanet-zerocarbonfuture.Forthisreason,thenationalenergytransitionandinternationalexamplesarediscussed.4.1IntegratedsolarPVholdsuntappedpotentialforcitiesInChina,theinstallationofdistributedsolarPVsystemshasbeenacceleratinginrecentyears.Theirsharehasreached32.2%ofthenationaltotalPVinstalledcapacity,yetthisisstillmuchlowerthanthetargetof55%setinthe13thFive-YearEnergyDevelopmentPlan(2015-2020)(NEA,2017)Recently,theChineseNationalEnergyAdministrationissuedapolicytoencouragetheinstallationofon-sitedistributedenergygenerationbyrequiringpilotcitiesandtownstoallocateatleast50%ofpublicbuildingrooftopareas,andatleast40%ofindustrialandcommercialbuildingrooftopareas,tosolarPV(China5e.com,2021).Forthefirsthalfof2021,distributedsolarPVinstallations(7.65gigawatts[GW])accountedforcloseto60%ofthesolarPVaddition,accordingtotheNationalEnergyAdministration(NEA,2021a).Thistrendisexpectedtocontinuethankstothemultiplebenefitsofon-siterenewableenergygeneration,includingimprovedelectricityquality,lessenergylossinlong-haultransmissionnetworks,avoidedinvestmentintransmissionnetworkexpansion,improvedlocalenvironmentalquality,jobcreation,andeconomicopportunitiesbenefitinglocalcommunities.FortheWuzhongDistrict,thelimitedlocalrenewableenergyresourcesandtheconstraintsonlanduseimpedegreateruseoflocalrenewablesbeyondtherenewableenergytechnologiesconsideredinthemodel.Ofthelocallyavailablerenewableenergysourcesinthedistrict,integratedsolarPVinbuildingsandurbaninfrastructureappearstoholdthegreatestpotential.BIPVcansignificantlyexpandavailablesurfaceareaforsolarPVelectricitygeneration.Thisisparticularlytrueforanareawithhigh-risebuildings,whererooftopareasgenerallyrepresentNETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA47asmallportionofthebuildingenvelope.Withfaçade-integratedPV,thebuildingcangeneratenotonlymoreelectricitybutmuchsmootherdailygenerationoutputthanrooftopPVsystemsalone,asthePVpanelsonthefaçadescancontinuetogenerateelectricityatsmallersolaraltitudeangles,fromwhichthepanelsontherooftopsgeneratelesselectricity.This,ineffect,widenstherangeofsolaraltitudeanglesforelectricitygenerationcomparedwiththeuseofinstalledrooftopPVsystemsalone.PilotprojectsacrosstheglobehavedemonstratedsignificantreductioninelectricitydemandinbuildingswithBIPVinstallations.Overthepastdecade,BIPVshavemadesubstantialprogressintechnologydevelopmentanddeployment.Suchprogresshasbeendemonstratedthroughagrowingnumberofpilotandcommercialprojectsacrosstheglobe,generatingpositivefeedbackfrompolicymakers,urbanplanners,energyandconstructionsectors,andend-users(SolarPowerEuropeandETIPPV,2019).Someexamplesare:•Treurenbergofficebuilding,Brussels(Belgium):Thisisthefirstnet-zeroenergybuildingtobecertifiedBREEAM(BuildingResearchEstablishmentEnvironmentalAssessmentMethodology)“Excellent”.Throughtheretrofittingprocess,1960sbuildingfaçadeswerecoveredwithBIPV,accountingfor61kilowattspeak(kWp)ofinstalledpowergenerationcapacity.Another61kWpwasinstalledontherooftops.Altogether,theBIPVsgenerateenoughelectricitytomeetthedemandofthebuilding.•TheSolarEmeraldcommercialbuilding,Drammen(Norway):ThisbuildingwasrenovatedtoachievehigherbuildingenergyperformancebyinstallingBIPVonallfaçades,withatotalgenerationcapacityof115kWp,andPVpanelsontheroofwithacapacityof68kWp.Annually,thepanelscangenerate106megawatthours(MWh)ofelectricity(55.5MWhfromBIPVand50.5MWhfromrooftopsolarPV).Thisissufficienttoprovide23%ofthetotalbuildingelectricalconsumption(BIPVNO,n.d.).•Enzianofficebuilding,Bolzano(Italy):Thisbuilding’sfaçadeswerecoveredasmuchaspossiblebyinsulatingglass(filledwithargongas)withamorphoussiliconmodulesoropaquelaminatedglass.SolarPVmoduleswerealsoinstalledontheroof.Annually,thesystemcanproduce113MWhofelectricityfromsolarenergy(EURAC,2013).InWuzhong,electricitytypicallyaccountsfortwo-thirdsofthetotalenergyconsumptionofbuildings.Therefore,BIPVscanplayaveryimportantroleindecarbonisingthebuildingsector,astheycouldsubstantiallycontributetothereductionofelectricitydemandfromthegrid,particularlyinsummerseasonswhentheelectricityconsumptionforairconditioners(onaverage,accountingforhalfofannualhouseholdelectricityconsumption)istypicallysoaring(Wang,2021).Nevertheless,BIPVisstillanichemarket,largelybecauseofitshighercostsduetofewerautomatedmanufacturingprocessesandfeweroptionsonthemarket,althoughprogressisrapidlyevolving(Kuhnetal.,2021).Intermsofcostoutlooks,teamingupthePVandconstructionindustrieshelpsreducecostswhileimprovingoverallperformancefrombothenergyandconstructionperspectives.BIPVsalsooffermorethanjustelectricitygeneration,includingthermalandacousticinsulation,replacingconventionalbuildingcomponentsandprovidinganaestheticallypleasingappearance.Hence,thereshouldbeafairwaytocomparetheircostprofileswithaconventionalPVsystemperformingasingularfunction.48Moreimportantly,foradistrictorcitywithambitionstoachievenet-zerocarbonemissionsorpositiveenergy,BIPVpresentsoneofthefewoptionstomaximisetheuseofsolarenergyresourcesincitieswhentheavailablerooftopareaislimited(Mose,LovatiandMaturi,2018).ThisisparticularlyrelevanttoChinesecities,wherethepopulationdensitiesaregenerallymuchgreaterthanthoseinEuropeorNorthAmerica.ThissuggeststhatthelargemarketpotentialinChinaforBIPVwouldbeabletobringdownthecostandspurinnovationfornewdesignstobettermeettheneedsforenergyandbuildingmaterials.Inadditiontobuildings,urbaninfrastructuresuchasparkinglotcanopiesandpavementscanofferpotentialsurfaceareasforintegratedsolarPV.Forinstance,inanefforttocreateapositiveenergydistrict,Groningen–thelargestcityinthenorthernNetherlands–willturncurrentbicyclelanesintoapowerplantbyintegratingsolarPVpanelsintothesurface,whichwillproduce60MWhofelectricityannually(MakingCity,2019).SuchintegrationwouldenhancepublicacceptanceofsolarPVsolutionsinthebuiltenvironment,wherethesocialdimensionplaysacriticalrole.ThepotentialforapplyingintegratedsolarPVaspartoftheurbanenvironmentisthereforehuge,yetitremainslargelyuntapped.WuzhongshouldexploreopportunitiestounlocksuchpotentialandshowcaseviabletechnologicalandbusinesssolutionsforChina.4.2Enhancingdemand-sideflexibilityinsupportofgridintegrationofrenewablesGridflexibilityisessentialforscalinguptheintegrationofvariablerenewableenergytechnologiesintothepowergridaspartofthedecarbonisationoftheenergysector.Thechallengestypicallygrowwithincreasingsharesofvariablerenewableenergysources.InChina,electricityfromsolarandwindenergyisexpectedtosupply11%ofthenationalelectricityconsumptionbytheendof2021,animportantmilestoneleadingtotheproposedtargetsetforthe14thFive-YearEnergyPlan(2021-2025):non-fossilfuelenergysourcescontributingto20%oftotalprimaryenergyconsumptionby2025(NEA,2021b).Ithasbeenestimatedthatvariablerenewableelectricitywillaccountfor20%ofthetotalelectricitygenerationby2030(NDRC,2021).Therefore,thisdecade(2020-2030)isatestperiodforChinaontheextenttowhichthecountrycanrelyonrenewablestoachieveits2060target.ItdependsonwhetherChinacanfindareliable,sustainableandaffordablemechanismtoprovidetheflexibilitythatthefutureenergysystemwouldneed.Currently,themajorityoftheresponsibilitydependsonthetwogridoperatorsinChina,theStateGridandtheSouthernGrid,toensuregridintegrationoftheplannedquotaofrenewable-basedpowergenerationcapacity.Thepresentenergyflexibilityoptionsfromthesupply-sideinChinaprimarilyincludepumpedstoragehydropowerstations,naturalgas-firedpowerplantsandflexiblecoal-firedpowerplantsservingasaregulatingpowerinsteadofservingbaseloaddemand.However,allofthemarefacingseriouschallengesinsupportinggridoperationunderhighsharesofvariablerenewableenergysources.Thereareregulatoryandtechnicalbarriers,forexamplealackofmarketconditionsforancillaryserviceprovision.Yet,moreimportantly,thesupply-sideflexibilitycapacitieswouldnotbesufficientalonetomeettheflexibilitythatwouldbeneeded,duetosuchconstraintsasinsufficientavailabilityofresources,environmentalconcerns,andlackofinstitutionalandregulatoryharmonisation.Withtheinstalledpowergenerationcapacityfromvariablerenewablesreachingaboutone-quarterofthenationaltotal,andbeinginrelativelygeographicallydistributedregions,thechallengewillbecomegreaterifnotdealtwithinasystematicfashion.NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA49Currently,renewableenergydevelopersareencouragedtoprovideadditionalflexibilityiftheywouldliketoinstallmorethanispermittedundertheapprovedcapacityadditionplan.Theycanacquiresuchflexibilitybybuildingphysicalsystemsorpurchasingsuchservicesonthemarketplace.Overtime,thisoptionwouldbeexpectedtobecomemainstream.Inotherwords,agridauxiliaryservicemarketwouldneedtobeestablishedandflexibilitywouldbeanenergycommoditythatwouldbepricedunderasetofnewrulesaspartofongoingpowermarketreforminChina.Inthiscontext,exploringtheflexibilityoptionsthatthedemand-sidecanprovidebeyondconventionalinterruptibleloadmanagementschemesisnotonlytechnicallynecessarybuteconomicallysensible.Thisisoneofthecriticalrolesthatcitiesasloadcentrescanplayintheglobalenergytransition,particularlythosecitieswithoutexcellentlocalrenewableenergyresources.Atpresent,suchadditionalflexibilityoptionsarelimitedtopower-to-heatandelectromobility,giventechnologicalconstraintsandthesystemconfiguration(IRENA,2019b).Lookingforward,alongwithsmartcitydevelopment,agrowingnumberofelectricalappliancesarebeingdigitalisedandconnectedtotheInternetandwouldthusbetheoreticallycontrollable.AccordingtotheInternationalEnergyAgency,therewillbe83billionconnectedelectricandelectronicdevicesandsensorsby2024(IEA,2021).TheenergyconsumptionprofilesofInternet-connectedappliancescouldbealteredtomatchgenerationcurvesfromvariablerenewableenergyelectricitygenerationifdigitalisedintelligentenergydemand-sidemanagementsystemswereputinplace.Byharnessingpotentialflexibilitythroughintelligentenergymanagementsystems,citieswouldbewellpositionedtoprovidetechnicalsupportthatthegrid(bothpowerandthermal)operatorswouldneedtosupportgrowingsharesofvariablerenewablesinsystemsaspartofthedecarbonisationstrategy.ForWuzhong,itwouldbeadvisabletofocusonsolvingChina’sfutureproblemswhileweaningoffoftoday’sfossilfuel-dominatedenergysystems–specifically,bybuildingtheflexiblecapacitythatregionalornationalpowergridswouldneed.Practicallyspeaking,electrificationoftransportandbuildingsectorsshouldbegivenpriorityintheimmediateterm,whileinthemediumtolongterm,flexibilitycanbeprovidedthroughflexibleorcontrollablehomeappliancesthatmodifytheirconsumptionprofiles(eitherbyreducingorshiftingtheirloadstodifferentperiods).Forthelatter,theaggregator5isacrucialplayer,offeringthepossibilityforsmallconsumerstoparticipateintheflexibilitymanagementrequiredbythedistributiongridsand,thus,supportingtheaccommodationofhighersharesofvariablerenewablesandreducingthecarbonfootprintofgridelectricity.4.3RoleofgreenhydrogenGreenhydrogenisproducedviaelectrolysispoweredbyrenewableelectricity.Thankstoitsflexibleproductionusingelectrolysers,itcanbeusedasanenergycarrierthateffectivelystoreselectricalenergyharnessedfromvariablerenewableenergysources,suchassolar5.Anewplayerintheenergymarket,theaggregatorrepresentsaclusterofsmalleragentsinanenergysystem.Benefitingfromadvancedinformationandcommunicationtechnologiesandenergymanagementtechniques,theaggregatorfunctionsasaunitedentityintransactionsofgridservicesprovidedtothegridorotherengagementsintheenergymarket(IRENA,2020c;MIT,2016).50andwindenergy.Itsapplicationscanalsobeextendedtoend-usesectorsotherthandistributedstationaryenergygeneration,suchasthetransportationsectorthroughfuelcellautomobiletechnologies,thechemicalindustry,andiron-makingbyreplacingcokecoalasadirectagent.Itcanalsobeusedtodecarboniseend-usesectorsthatarehardtodecarbonisethroughanelectrificationapproach.Fromthisperspective,greenhydrogenwouldplayanimportantroleindrivingtheglobalenergytransitiontowardsacarbon-neutral2050(IRENA,2018).Inrecentyears,Chinahassignificantlyelevatedthestrategicrolethathydrogenwillplayinacceleratingitsnationalenergyrevolution.AftertheChinesepresidentannouncedinSeptember2019thatChinawouldachievecarbonneutralityby2060,hydrogenhasswiftlybeenviewedasaplausibletechnologicalpathwaytocontributetoachievingthisambitiousgoal,despitesomeexpertswarningthatChinashouldtakeslowstepsgiventhelackofclarityonhowthehydrogen-for-decarbonisationstrategywillunfoldandthefactthatChinawilllikelyrelyonfossilfuel-basedhydrogenatleastfortheshortterm.TheChinaHydrogenAllianceprojectsthatChinawillproduce37.15milliontonnesofhydrogenannually,contributingto5%ofthetotalfinalenergyconsumptionin2030,ifcarbonemissionspeakinthatyear.However,only13%ofthiswillqualifyasgreenhydrogen,accordingtothewhitepaperonChina’shydrogenenergyandfuelcellindustry(ChinaHydrogenAlliance,2019),launchedinApril2021.Toachievecarbonneutralityby2060,Chinawouldneed130milliontonnesofhydrogen,accountingfor20%ofthetotalfinalenergyconsumption,ofwhich80%isexpectedtobegreenhydrogentobeproducedfrom500GWofelectrolysers,contributingtonearly17%ofChina’scurrentcarbonemissions.Suzhoucity,towhichWuzhongDistrictbelongs,ispartoftheYangtzeRiverDeltaregion,regardedasoneofthethreehydrogenindustrypioneersinChina(Mengetal.,2020).Thecityreleasedawhitepaperonhydrogenindustrydevelopmentinearly2021(GovernmentofSuzhou,2021).Itnotonlypresentstheecosystemforthehydrogenindustry’sdevelopmentinSuzhoubut,moreimportantly,setsthegoalsfor2035:creating15billionUSDworthofbusinessesaroundhydrogen,promotingtheuseofhydrogenfuelcellvehiclesandbuilding70hydrogenrefuellingstations,amongothers.Atthecurrentstage,thecityhasestablisheddesignatedindustrialzonesforcompaniestosetupmanufacturingcapacitiesforhydrogenfuelcellvehicles(GovernmentofSuzhou,2021).ItwouldbesensibleforWuzhongtobenefitfromthelocaldevelopmentofthehydrogenindustryinSuzhoucitybyexpandingitstransportdecarbonisationintoheavy-dutyandlong-haultrucks,forwhichhydrogenfuelcelltechnologiesholdsubstantialpotentialinthelongrun(IRENA,2018).Asimportantly,WuzhongshouldparticipateactivelyinhydrogenindustrydevelopmentinSuzhou,includingencouraginginvestorsanddeveloperstobuildhydrogenproductionequipmentmanufacturingfacilitiesandbuildinghydrogenrefillingstations,alongwithfuelcellelectricvehicles,inthedistrict.4.4ImportanceofsustainableurbanenergyplanningOverall,twokeypathwaysareidentifiedinthisstudythroughwhichtheWuzhongDistrictcouldmovetowardsnet-zeroemissions:throughsupply-sidetechnologysolutionsand/orthroughdemand-sidemanagement.Bothareneededtoscaleuptheuseofrenewablesattheregionalandnationallevels.However,howtostrikeasoundbalancewoulddependonhowsoundlyaNETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA51sustainableenergyplancanbedevelopedandimplemented.Soundplanningisvitallyimportantbecause,owingtothelonglifespanofthephysicalenergyinfrastructure,theplanningcaneitherleapfrogacityoverorlockitintoacertainenergydevelopmenttrajectory.Onthegloballevel,soundplanningisevenmoreimportant,particularlyduringthepost-COVIDperiod,whenmanymunicipalgovernmentsmayfallshortoffinancialresourcesasaconsequenceofoverspendingandlackoftaxationrevenuesduringthepandemic.Agrowingnumberoforganisationshavedevelopedinstrumentstoassistlocalenergyexpertsandauthoritieswithurbanenergyplanning(Hemis,2017;Sahebetal.,2014).Severalresourcesprovidedetailedstep-by-stepguidelinesonhowtodevelopandimplementasustainableenergyplanforcities.Thekeystepsaredescribedinthefollowingtext(EU,2010;ICLEI,2011;ICLEI,UN-HabitatandUNEP,2009).•Baselinereview:Thisinitialstep,partiallyaddressedbythisstudyforWuzhong,involvesconductingadetailedCO2emissionsinventory.Thedevelopmentofatrack-and-tracecarbonemissionsmanagementplatformcanhelpidentifythehighestpollutingagents(e.g.specificenterprisesorservices)inasystem.Sustainabilityprojects(e.g.demand-sidemanagementorrenewableenergyprojects)canthenbetargetedtowardshigh-priorityorhigh-impactsectors.•Targetsetting:Withacarbonmanagementplatforminplace,thenextkeystepistoestablishtargets.Studies,suchasthisone,shouldinformtargetsetting.Targetsmaypertaintoemissionreductions,renewableenergyshares,andefficiencymeasures,aswellasotherobjectives,indicatorsandmeasurabletargets.Localstakeholdersshouldbeengagedatalllevelstodefinemeaningfultargets.ForWuzhong,thismeanstargetsshouldbesetwithreferencetoandinalignmentwiththeemissionreductiongoalsofSuzhoucity.•Politicalcommitmentandpartnership:Thisstepinvolvesformalisingthecommitmenttodevelopingandsupportingasustainabilityplanbydifferentagenciesincities.Thelocalgovernmentshouldalsoinvolveandestablishpartnershipswithkeystakeholders;thisisoftenidentifiedasafactorthatstronglyinfluencesthedurationandthesuccessorfailureoftheplanningprocess.•Implementationplan:Adetailedplanshouldbedevelopedandimplementedinaccordancewithestablishedtargetsandgoals.Programmeandprojectfinancingmustalsobedefinedwithsupportingpartners.•Monitoringandevaluation:Inthisstage,theprogress,impacts,successesandfailuresoftheimplementedactionplanarecarefullymonitoredandevaluated.Thecarbontracingplatformestablishedinthefirststagewillassistinthisphaseaswell.Iterativeadjustmentstotheimplementationplanandsupportingstructuresmayberequired.Theimportanceofintegratingacity’ssustainableenergyplanintotheoverallurbanplanningatanearlystageshouldbeemphasised.Resourcemapping,urbanformsandfunctionalities,andcouplingofdifferenturbaninfrastructureandend-usesectorsareallimportantvariablesfordevelopingasolidandsustainableurbanenergyplan.Morerecently,ithasbecomeincreasinglyrelevantandimportantfortheclimateresilienceofurbanenergysystemstobefactoredintolong-termplanning,giventhelonglifespanofinfrastructureandtheincreaseintheseverityandfrequencyofextremeweatherpatterns,whichposerealandsustainedthreatstourbaninfrastructureanddwellers,economies,livelihoodsandthecontinuedurbanisationprocess.525©DanielHanscom/GettyImages5NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA53CONCLUDINGREMARKSChinahassetcleartargetstoachieveitscarbonpeakby2030andcarbonneutralityby2060.Thecountrywillbelesslikelytodeliveronitsambitionifcitieslagintakingaction.Therefore,itiscrucialforlocalauthoritiestomakealong-termenergytransitionstrategytowardscarbonneutrality.Authoritiesmustguidecitiestoimplementadequateactionstodecarbonisetheireconomies.Bydoingso,theywillalsopreventthemselvesfrombeinglockedintoaportfolioofcarbon-intensivestrandedassetswhencarbon-intensivecommoditiesbecomecost-prohibitiveinfuture.However,areaswithmodestrenewableenergyresources,liketheWuzhongDistrict,needtogiveseriousconsiderationtoemergingandinnovativerenewableenergytechnologiestomaximisetheuseoftheirlimitedresources.Theconventionalmodellingapproachcouldpresentalimitation,ascarbonreductionbyswitchingfromhightolowercarbon-intensivefossilfuelsandthroughCCSisnormallygivenpriorityintheoptimisationprocess.Forthisstudy,fourscenarioswerebuiltonthebasisoftheresultsfromadistrict-wide,energysystemoptimisationmodel.Inallscenarios,therenewableenergypotentialsarenotfullyunlockedateitherthelocalorregionallevel.Overall,thetwomainpathwaysforWuzhongtoachievealow-carbonemissionsfuturearethroughlow-carbongenerationtechnologiesanddemand-sidemanagementstrategies,includingefficiencymeasures.Theyarenotmutuallyexclusive.Themaximiseduseoflocalrenewableenergyresourcesrequiresenhanceddemand-sidemanagement,whichoftenhasanimportantroletoplayinfacilitatingtheintegrationofrenewablesattheregionallevel.Renewableenergytechnologies–includingPV,waste-basedCHPanddecentralisedboilers–shouldbemaximallydeployedinWuzhongandgivenpriorityintheplanningprocess.Giventhelimitedpotentialofthesetechnologies,however,supplementarynaturalgas-basedfacilitieswouldbeneededtodecarbonisetheenergymixinthelongtermifthecarbonintensityofregionalgridelectricityremainsrelativelyhigh.Thedeploymentratesandcapacitiesofthesetechnologiesdependalsoonvariousfactors,includingexpectedenergydemandgrowthrates,andhowaggressivelycarbonemissiontargetsareset.CCStechnologiesalsodemonstratepotentialtoreduceemissionsdrasticallybutmaybebettersuitedforimplementationonaregionalscale,whichwouldyieldbenefitslocally(e.g.throughdecarbonisationoftheregionalelectricitygrid).Withtheabove,Wuzhongcouldsubstantiallyreduceitscarbonemissionsby2050.However,theimplementabilityofthecarbonabatementoptionsfromthemodellingresultsappeartobesubstantiallydependentonkeyassumptions,whichdeservefurtheruncertaintystudies.54Nonetheless,themodellingandscenarioexercisesareveryhelpfulintermsofunderstandingtheconventionaldecarbonisationapproach.This,inturn,helpslocalauthoritiesstretchthelinesofthinkingbeyondconventionaloptions.Thestudyhasidentifiedfourstrategicareasenablingexpansionofthedecarbonisationoptionspresentedinthemodellingresults:BIPV,demand-sideflexibility,greenhydrogenandurbanenergyplanning.TheseareasareapplicablenotonlyforWuzhongbutformanydistrictsandcitieslikeWuzhong,withmodestlocalrenewableenergyresourcesandrelativelyhighenergydemand.Theprovisionofdemand-sideflexibilityatthedistributionlevelcouldfacilitatetheintegrationofvariablerenewableenergysourcesattheregionallevel,thussignificantlyreducingthecarbonintensityoftheregionalgridelectricity.Therefore,theneedfortransmissioncapacityenhancementorexpansiontotransmitrenewableelectricitytotheendusers,inthiscasetoWuzhongDistrict,shouldalsobeassessedandoptimisedinconcertwiththeplannedregionalscale-upofvariablerenewableenergydeployment.Certainly,thesestrategicareasdonotconstituteanexhaustivelist,buttheydohighlightthemostrelevantaspectsthatsuchcitiesordistrictsshouldlookintoandadjusttosuitconditionsintheirlocalities.TheChineseleadershiphasboosteditsambitionandsteppedupitseffortsinaddressingtheclimatechallenges.Citieswilltakethisasguidanceandmakecorrespondingstrategiesandactionsplanstocontributeasmuchastheycantoachievingthenationalcarbonpeakby2030andcarbonneutralityby2060.However,theactionstheytakeandthedecisionstheymakeshouldbebasedontheirresources.Forcitieswithoutsufficientlocalrenewableenergyresources,thereareotheroptionstheycouldexplorewiththeaimofachievingnet-zerocarbonemissionsinacollectiveandcollaborativefashion.NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA55REFERENCESAminov,Z.,etal.(2016),“Evaluationoftheenergyefficiencyofcombinedcyclegasturbine.CasestudyofTashkentthermalpowerplant,Uzbekistan”,AppliedThermalEngineering,Vol.103,pp.501-509.BIPVNO(n.d.),“BuildingintegratedphotovoltaicsforNorway.Case:Solsmaragden”,http://bipvno.no/_wp1_solsmaragden.html.Brown,R.G.(1956),ExponentialSmoothingforPredictingDemand,ArthurD.Little,Inc.,Massachusetts,www.industrydocuments.ucsf.edu/tobacco/docs/#id=jzlc0130.Cai,B.F,Q.LiandX.Zhang(2021),ChinaCCUSAnnualReport:Roadmap2021[inChinese],EnvironmentalPlanningInstituteofMinistryofEcologyandEnvironmentofChina,InstituteofRockandSoilMechanicsofChineseAcademyofSciences,AdministrativeCenterforChina’sAgenda21,https://sisd.org.cn/express/express426.html(accessed15December2021)Cao,Y.,etal.(2019),ResearchandAnalysisReportonPeakCarbonEmissionsinSomeRegions[inChinese],NationalCenterforClimateChangeStrategyandInternationalCooperation,Beijing,www.ncsc.org.cn/yjcg/dybg/201904/W020190424561852321323.pdf(accessed28August2020).Chai,C.(2018),"Aregreenbuildingsexpensive?"[inChinese],Construction21,www.construction21.org/china/articles/cn/绿色建筑成本昂贵.html(accessed10September2020).China5e.com(2021),"NationalgovernmentadvancingdistributedgenerationsolarPVapplications"[inChinese],www.china5e.com/news/news-1117660-1.html.ChinaHydrogenAlliance(2019),"WhitePaperonChina’shydrogenenergyandfuelcellindustry"[inChinese],http://h2cn.org.cn/publicati/215.html.ChinaPower(2019),“AnalysisofheatingsituationinthesouthofChina"[inChinese],www.chinapower.com.cn/jdtt/20190122/1263640.html(accessed1June2020).CodeofChina(2019),AssessmentStandardforGreenBuilding,NationalStandardGB/T50378-2014,www.codeofchina.com/standard/GBT50378-2019.html(accessed10September2020).CNBS(2021),China2020StatisticsReportforSocialandEconomicDevelopment[inChinese].ChineseNationalBureauofStatistics,Beijing,www.stats.gov.cn/tjsj/zxfb/202102/t20210227_1814154.html.CSEIRI(2017),ResearchonChinaIndustrialBoilerEnergyEfficiencyIndicatorsandEvaluationSystemProjectReport[inChinese],ChinaSpecialEquipmentInspectionandResearchInstitute,Beijing.Edenhofer,O.,etal.(2014),“Technicalsummary”,inClimateChange2014:MitigationofClimateChange.ContributionofWorkingGroupIIItotheFifthAssessmentReportofthe56IntergovernmentalPanelonClimateChange.CambridgeUniversityPress,CambridgeandNewYork,www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_technical-summary.pdf.EngineeringToolBox(2009),"Combustionoffuels–carbondioxideemission",www.engineeringtoolbox.com/co2-emission-fuels-d_1085.html.Eriksson,O.,andG.Finnveden(2017),"Energyrecoveryfromwasteincineration–TheimportanceoftechnologydataandsystemboundariesonCO2emissions",Energies,Vol.10/4.EU(2010),HowtoDevelopaSustainableEnergyActionPlan–Guidebook.EuropeanUnion,Luxembourg,www.pilsetumerupakts.eu/IMG/pdf/SEAP_guidebook_Part_I.pdf.EURAC(2013),"Enzianoffice",EuracResearchInstituteforRenewableEnergy,https://bipv.eurac.edu/en/case-studies/enzian-office.html.Fortum(n.d.),"Afull-scalecarboncaptureandstorage(CCS)projectinitiatedinNorway",www.fortum.com/media/2018/11/full-scale-carbon-capture-and-storage-ccs-project-initiated-norway(accessed26August2020).Fridley,D.,etal.(2001),TechnicalandEconomicAnalysisofEnergyEfficiencyofChineseRoomAirConditioners,EnvironmentalProtectionAgency,Washington,DC.Fuentes,E.,L.ArceandJ.Salom(2018),“Areviewofdomestichotwaterconsumptionprofilesforapplicationinsystemsandbuildingsenergyperformanceanalysis”,RenewableandSustainableEnergyReviews,Vol.81,pp.1530-1547.Gielen,D.,andC.H.Chen(2001),"TheCO2emissionreductionbenefitsofChineseenergypoliciesandenvironmentalpolicies:AcasestudyforShanghai,period1995–2020",EcologicalEconomics,Vol.39,pp.257-270.GovernmentofChina(2021),中共中央国务院关于完整准确全面贯彻新发展理念做好碳达峰碳中和工作的意见[GuidancefromtheChineseCommunistPartyandtheStateCouncilonImplementingtheNewDevelopmentConceptandEnsuringtheAchievementofCarbonPeakingandNeutrality],GovernmentofChina,Beijing,www.gov.cn/zhengce/2021-10/24/content_5644613.htm.GovernmentofSuzhou(2021),"Whitepaperonhydrogenindustrydevelopment"[inChinese],www.suzhou.gov.cn/szsrmzf/szyw/202102/a4b998a8f49344cebbaf85c4ef974de7.shtml.Guo,J.,N.Z.KhannaandX.Zheng(2016),"ElectricitydemandinChinesehouseholds:FindingsfromChinaresidentialenergyconsumptionsurvey",inACEEESummerStudyonEnergyEfficiencyinBuildings,http://aceee.org/files/proceedings/2016/data/papers/9_76.pdf.Hemis,H.(2017),IntegratingEnergyinUrbanPlanningProcesses–InsightsfromAmsterdam/Zaanstad,Berlin,Paris,Stockholm,Vienna,WarsawandZagreb,SynthesisreportofWorkPackage4,UrbanLearning,EuropeanCommission,Brussels,www.urbanlearning.eu/fileadmin/user_upload/documents/D4-2_Synthesis-report_upgraded_processes_final_170807.pdf.Herzog,H.,etal.(2005),"Costandeconomicpotential",inCarbonDioxideCaptureandStorage,B.Metzetal.,eds,CambridgeUniversityPress,NewYork,www.ipcc.ch/site/assets/uploads/2018/03/srccs_chapter8-1.pdf.NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA57IBM(n.d.),“IBMSPSSStatistics”,webpage,www.ibm.com/products/spss-statistics(accessed15June2020).ICLEI(2011),SustainableNOW–WaystoSuccessfulSustainableEnergyActionPlanninginCities,LocalGovernmentsforSustainability,Freiburg,https://ec.europa.eu/energy/intelligent/projects/sites/iee-projects/files/projects/documents/sustainable_now_final_brochure_en.pdf.ICLEI,UN-HabitatandUNEP(2009),SustainableUrbanEnergyPlanning–AHandbookforCitiesandTownsinDevelopingCountries,LocalGovernmentsforSustainability,UN-HabitatandUnitedNationsEnvironmentProgramme,www.mypsup.org/library_files/downloads/SustainableUrbanEnergyPlanning.pdf.IEA(2021),EmpoweringCitiesforaNetZeroFuture,InternationalEnergyAgency,ParisIEA-ETSAP(2014),EnergySupplyTechnologiesData(database),InternationalEnergyAgency,Paris,https://iea-etsap.org/index.php/energy-technology-data/energy-supply-technologies-data(accessed23October2020).IPCC(2018),SummaryforPolicymakersofIPCCSpecialReportonGlobalWarmingof1.5°C(approvedbygovernments),IntergovernmentalPanelonClimateChange,www.ipcc.ch/2018/10/08/summary-for-policymakers-of-ipcc-special-report-on-global-warming-of-1-5c-approved-by-governments.IRENA(2021),WorldEnergyTransitionsOutlook:1.5°CPathway,InternationalRenewableEnergyAgency,AbuDhabi,www.irena.org/publications/2021/Jun/World-Energy-Transitions-Outlook.IRENA(2020a),RiseofRenewablesinCities,InternationalRenewableEnergyAgency,AbuDhabi,https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2020/Oct/IRENA_Renewables_in_cities_2020.pdf.IRENA(2020b),ReachZerowithRenewables,InternationalRenewableEnergyAgency,AbuDhabi,https://irena.org/-/media/Files/IRENA/Agency/Publication/2020/Sep/IRENA_Reaching_zero_2020.pdf.IRENA(2020c),BusinessModels:InnovationLandscapeBriefs,InternationalRenewableEnergyAgency,AbuDhabi,www.irena.org/publications/2020/Jul/Business-Models-Innovation-Landscape-briefs.IRENA(2019a),Zhangjiakou:EnergyTransformationStrategy2050,InternationalRenewableEnergyAgency,AbuDhabi,www.irena.org/-/media/Files/IRENA/Agency/Publication/2019/Nov/IRENA_Zhangjiakou_2050_roadmap_2050.pdf.IRENA(2019b),Demand-sideFlexibilityforPowerSectorTransformation,InternationalRenewableEnergyAgency,AbuDhabi,www.irena.org/publications/2019/Dec/Demand-side-flexibility-for-power-sector-transformation.IRENA(2018),HydrogenfromRenewablePower:TechnologyOutlookfortheEnergyTransition,InternationalRenewableEnergyAgency,AbuDhabi,www.irena.org/-/media/Files/IRENA/Agency/Publication/2018/Sep/IRENA_Hydrogen_from_renewable_power_2018.pdf.58Jiang(2003),“LoadanalysisforresidentialconsumptionoversummerinNanjingcity”[inChinese],电力系统保护与控制(PowerSystemProtectionandControl),Vol.31/4,pp.6-24.Karim,S.M.,etal.(2017),"Co-benefitsoflowcarbonpoliciesinthebuiltenvironment:Aninvestigationintotheadoptionofco-benefitsbyAustralianlocalgovernment",ProcediaEngineering,Vol.180,pp.890-900.Kirchner,A.,etal.(2012),DieEnergieperspektivenfürdieSchweizbis2050,Basel,www.bfe.admin.ch/php/modules/publikationen/stream.php?extlang=de&name=de_564869151.pdf.Kuhn,E.T.,etal.(2021),"Reviewoftechnologicaldesignoptionsforbuildingintegratedphotovoltaics(BIPV)",Energy&Buildings,Vol.231,www.sciencedirect.com/science/article/pii/S0378778819339155.Lietal.(2018),“Casestudyonoptimizationschemedesignbasedonloadpredictionforregionalheatingsysteminindustrialcommunity",EnergyProcedia,Vol.145,pp.319-326.Liang(2019),FiveTrendsofChinesePopulationintheNext30Years[inChinese],ZhongtaiSecurities,www.yanjiubaogao.com/cha_kan_pdf?id=75942.Lin,F.,etal.(2011),"PerformancestudyofaninnovativenaturalgasCHPsystem",EnergyConversionandManagement,Vol.52/1,pp.321-328.Liu,Y.(2012),“Exponentialsmoothingmethodsandapplications“[inChinese],投资与合作(InvestmentandCooperation),Vol.4,pp.167-168.Lyons,M.,P.DurrantandK.Kochhar(2021),ReachingZerowithRenewables:CapturingCarbon,InternationalRenewableEnergyAgency,AbuDhabi,www.irena.org/-/media/Files/IRENA/Agency/Technical-Papers/IRENA_Capturing_Carbon_2021.pdf.MakingCity(2019),"Groningen",LGISustainableInnovation,http://makingcity.eu/groningen.McKinsey&Company(2021),CarbonNeutralityby2060:HowChinaEnergizesCitiesinAchievingtheTarget?[inChinese],www.mckinsey.com.cn/wp-content/uploads/2021/03/2021-McKinsey_Urban-decarbonization.pdf.Meng,X.,etal.(2020),"StatusquoofChinahydrogenstrategyinthefieldoftransportationandinternationalcomparisons",InternationalJournalofHydrogenEnergy,Vol.46/57,pp.28887-28899,https://doi.org/10.1016/j.ijhydene.2020.11.049.MIT(2016),TheValueofAggregatorsinElectricitySystems,MITCenterforEnergyandEnvironmentalPolicyResearch,Cambridge,MA,http://energy.mit.edu/publication/the-value-of-aggregators-in-electricity-systems.Mose,D.,M.LovatiandL.Maturi(2018),"Photovoltaiccity:Effectiveapproachestointegratedurbansolarpower",inUrbanEnergyTransition:RenewableStrategiesforCitiesandRegions(2nded.),editedbyPeterDroege,Elsevier.NDRC(2021),"Noticeonencouragingrenewablepowergeneratorstoenhancegridintegrationcapabilitythroughowningorpurchasingregulatingpowercapacity"[inChinese],NationalNETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA59DevelopmentandReformCommissionofChina,www.ndrc.gov.cn/xxgk/zcfb/tz/202108/t20210810_1293396.html.NEA(2017),"The13thFive-YearEnergyDevelopmentPlan"[inChinese],NationalEnergyAdministrationofChina,http://www.nea.gov.cn/135989417_14846217874961n.pdfNEA(2021a),"Energyupdateforthefirsthalfof2021"[inChinese],NationalEnergyAdministrationofChina.www.nea.gov.cn/2021-07/29/c_1310093667.htm.NEA(2021b),"NoticeonSolarPVandWindProjectDevelopmentfor2021"[inChinese],NationalEnergyAdministrationofChina,www.nea.gov.cn/2021-06/05/c_139993085.htm.Owens,B.(2014),TheRiseofDistributedPower,GeneralElectric,www.eenews.net/assets/2014/02/25/document_gw_02.pdf.ProjectCCS(2019),CarbonCaptureOslo,FortumOsloVarme,Oslo,https://ccsnorway.com/wp-content/uploads/sites/6/2019/09/fortum_oslo_varme.pdf.Ramachandran,K.,andH.Turton(2014),SwitzerlandEnergyTransitionScenarios–DevelopmentandApplicationoftheSwissTIMESEnergySystemModel(STEM),PaulScherrerInstitut,Bern,www.psi.ch/eem/PublicationsTabelle/2014-STEM-PSI-Bericht-14-06.pdf(accessed22April2016).Ramachandran,K.,andH.Turton(2013),"Along-termelectricitydispatchmodelwiththeTIMESframework",EnvironmentalModeling&Assessment,Vol.18/3,pp.325-343.Saheb,Y.,etal.(2014),Guidebook:HowtoDevelopaSustainableEnergyActionPlan(SEAP)inSouthMediterraneanCities,EuropeanUnionJointResearchCentre,Brussels,https://e3p.jrc.ec.europa.eu/publications/guidebookhow-develop-sustainable-energy-action-plan-seap-south-mediterranean-cities.SGCERI(2019),ChinaUrbanEnergy2018[inChinese],StateGridCityandEnergyResearchInstitute,ChinaElectricPowerPress,Beijing.SolarPowerEuropeandETIPPV(2019),SolarSkins:AnOpportunityforGreenerCities,SolarPowerEuropeandEuropeanTechnologyandInnovationPlatformforPhotovoltaics,https://etip-pv.eu/publications/etip-pv-publications/download/solar-skins-an-opportunity-for-greener-citiesSolcast(n.d.),“SolcastAPIToolkit:HistoricalandTMY”,https://toolkit.solcast.com.au/historical(accessed1June2020).Tesfai,A.,etal.(2015),“Acasestudyanalysisofsystemefficiency,viabilityandenergyvaluesofSOFCbasedfuelcellmicro-CHPforofficebuildings”,ECSTransactions,Vol.68,pp.176-186.UNDESA(2019),The2019RevisionofWorldPopulationProspects,UnitedNationsDepartmentofEconomicandSocialAffairs,https://population.un.org/wpp/.UNECE(2016),TheCo-BenefitsofClimateChangeMitigation,SustainableDevelopmentBriefNo.2,UnitedNationsEconomicCommissionforEurope,https://unece.org/DAM/Sustainable_Development_No._2__Final__Draft_OK_2.pdf.60UNFCCC(n.d.),“TheParisAgreement”,UnitedNationsFrameworkConventiononClimateChange,https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement.Wang,Q.Y.(2021),EnergyData[inChinese],iGDPandEnergyFoundation,www.efchina.org/Attachments/Report/report-lceg-20210430-3/2020%E8%83%BD%E6%BA%90%E6%95%B0%E6%8D%AE.pdf.WRI(2020),OptimizationofSuzhou’sCarbonEmissionsPeakRoadmapandaLong-TermVisionfor2050[inChinese],WorldResourcesInstitute,Washington,DC.WuzhongDRC(2020),“Energystatistics”[inChinese],WuzhongDevelopmentandReformCommission,www.szwz.gov.cn/szwz/fzhgg/zwfw2.shtml.Yazdanie,M.,etal.(2016),“Well-to-wheelcosts,primaryenergydemand,andgreenhousegasemissionsfortheproductionandoperationofconventionalandalternativevehicles”,TransportationResearchPartD:TransportandEnvironment,Vol.48,pp.63-84,http://linkinghub.elsevier.com/retrieve/pii/S1361920916304564(accessed14July2017).Zhang,ChenandLiang(2006),“Analysisonhotwaterconsumptionforresidentialconsumers”,WaterSupplyandDischarge(给水排水),Vol.9,pp.71-74.Zhao,H.,X.HouandJ.Li(2018),“EnergysavinganalysisofCHPintheheatsupplymodification”,AdvancesinEnergyandPowerEngineering,Vol.06,No.01,pp.29-47.NETZEROPATHWAYSFORCITIES:THECASESTUDYOFWUZHONGDISTRICT,SUZHOU,CHINA63www.irena.org©IRENA2022

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