Waterforhydrogenproduction

?IRENA2023

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ISBN:978-92-9260-526-1

CITATION:IRENAandBluerisk(2023),Waterforhydrogenproduction,InternationalRenewableEnergyAgency,Bluerisk,AbuDhabi,UnitedArabEmirates.

ABOUTIRENA

TheInternationalRenewableEnergyAgency(IRENA)isanintergovernmentalorganisationthatsupportscountriesintheirtransitiontoasustainableenergyfutureandservesastheprincipalplatformforinternationalco-operation,acentreofexcellence,andarepositoryofpolicy,technology,resourceandfinancialknowledgeonrenewableenergy.IRENApromotesthewidespreadadoptionandsustainableuseofallformsofrenewableenergy,includingbioenergy,geothermal,hydropower,ocean,solarandwindenergy,inthepursuitofsustainabledevelopment,energyaccess,energysecurityandlow-carboneconomicgrowthandprosperity.

ABOUTBLUERISK

Blueriskisawaterstrategyanddataanalyticsconsultancyfocusedonenhancingresilienceandreducingriskinthefaceofemergingwaterchallenges.

Bluerisk

ACKNOWLEDGEMENTS

ThereportwasdevelopedundertheguidanceofUteCollieracting-Director,IRENAKnowledgePolicyandFinanceCentreandauthoredbyEmanueleBianco(IRENA),TianyiLuo(Bluerisk),andDivyamNagpal(ex-IRENA).

IRENAcolleaguesAnn-KathrinLipponer,LuisJaneiroandFranciscoBoshellprovidedvaluableinput.

AnetaCornell(Ecolab),LorenzoRosa(StanfordUniversity),ChaoZhangandYinshuangXia(TongjiUniversity),providedtechnicalcontributionstothereport.MarinaMelnikovaandYuryMelnikov(Mylonastars)providedusefulcontributionsandobservations.

Thereportbenefitedfromthereviewsandcommentsofexperts,includingAlistairWyness,RachaelRaid(BP),NitinBassi(CEEW),YuZhang,ZiyanSha(ChinaHydrogenEnergyIndustryPromotionAssociation),CristianCarraretto,RobertoGonzales(EBRD),AnetaCornell,EmilioTenuta(Ecolab),MassimoSantarelli(PolytechnicUniversityofTurin),AlejandroLongueira(RolandBerger)andSmeetaFokeer(UNIDO).

PublicationsupportwasprovidedbyFrancisFieldandStephanieClarke(IRENA).ThereportwaseditedbyFayreMakeig,withdesignprovidedbyElkanodata.

Forfurtherinformationortoprovidefeedback:publications@

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Tableofcontents

Glossary5

Executivesummary

6

Chapter1

Introductiontothehydrogen-waternexus

14

Chapter2

Areviewofwaterquantityrequirements

incommercial-scalehydrogenproduction

21

Chapter3

Waterfootprintandrisksofglobalhydrogenproduction

32

Chapter4

Deep-diveanalysesofnorthernChina,theGulfandEurope

42

Chapter5

ConclusionsandRecommendations

54

References

59

Appendix

63

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Figures

FigureS1

Acomparisonofaveragewaterwithdrawalandconsumptionintensitiesbyhydrogenproductiontechnology

7

FigureS2

Currentandprojectedfreshwaterwithdrawalforglobal

hydrogenproduction,bypathway

9

Figure2.1

Schematicsofprocess-specificwaterwithdrawalandconsumption

inlitresfortypicalhydrogentechnologiestogenerate1kilogrammeofhydrogen

24

Figure2.2

Shareofthewaterwithdrawalneedsofproductionandcoolingintheoverallwaterdemandofhydrogenproductionexamples

26

Figure2.3

Acomparisonofaveragewaterwithdrawalandconsumptionintensitiesbyhydrogenproductiontechnology

28

Figure2.4

Relationsbetweenhydrogenconversionefficiencyandwaterwithdrawalandconsumptionintensitiesofatypicalelectrolysisproject

30

Figure2.5

Annualwaterwithdrawaloftypicalhydrogenproductionprojects,thermalpowerplantsandmunicipalities

31

Figure3.1

Currentandprojectedfutureglobalhydrogenproductionunderthe1.5°CScenario

33

Figure3.2

Currentandprojectedfreshwaterwithdrawalforglobal

hydrogenproduction,bypathway

34

Figure3.3

Freshwaterforhydrogenproductionandcooling,todayto2050

36

Figure3.4

Globalwaterstressconditionsandgreenandbluehydrogenprojectlocationsfor2040

38

Figure3.5

Distributionofglobaloperationalandplannedgreenandbluehydrogenproductioncapacitiesbywaterstresslevel,

todayandin2040

40

Figure3.6

Distributionofglobaloperationalandplannedgreenandbluehydrogenproductioncapacitiesbywaterstresslevel

andregionin2040

41

Figure4.1

Hydrogen-producingcoalchemicalplantsandlevels

ofwaterstressintheYellowRiverBasin

42

Figure4.2

Annualwaterwithdrawalandconsumptionduetocoal-basedhydrogenproductionintheYellowRiverBasin,byprovince

43

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Figure4.3Distributionofhydrogen-producingcoalchemicalplants44

intheYellowRiverBasinbycurrentwaterstresslevel

Figure4.4Annualwaterwithdrawalandconsumptionrequirements45

ofcoal-basedhydrogenproductionintheYellowRiver

Basinunderfourscenarios

Figure4.5HydrogenplantsintheGulfCooperationCouncilcountries46

andtheregion’scurrentwaterstressconditions

Figure4.6Currentandprojectedfuturehydrogenproduction47

oftheGulfCooperationCouncilcountries

Figure4.7Currentandprojectedseawaterwithdrawalsanddesalinated48

seawaterrequirementsofhydrogenproduction

intheGulfCooperationCouncilcountries

Figure4.8AnoverviewofhydrogenprojectsinEurope

49

Figure4.9Amapofwaterstressandoperationalandplanned

50

hydrogenprojectsbyproductiontechnologyinEurope

Figure4.10ThedistributionofEurope’soperationalandplanned51

hydrogenprojectsbywaterstresslevelsin2040

Figure4.11CurrentandprojectedhydrogenproductioninEurope

52

Figure4.12Currentandprojectedfuturefreshwaterwithdrawaland

53

consumptionrequirementsofhydrogenproductioninEurope

Tables

Table2.1Asummaryofwaterwithdrawalandconsumptionintensities29

byhydrogenproductiontechnology

Table3.1Currentandprojectedfreshwaterwithdrawalandconsumption37

forhydrogenproduction(billioncubicmetres),todayto2050

TableA1Waterwithdrawalandconsumptionintensitydatasources

63

Boxes

Box3.1HydrogenintheWorldEnergyTransitionsOutlook

32

Box3.2Whatiswaterstress?

39

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Abbreviations

AEM

anionexchangemembrane

ATR

auto-thermalreforming

CCS

carboncaptureandstorage

CCUS

carboncapture,utilisationandstorage

GCCGulfCooperationCouncil

GHGgreenhousegases

H2hydrogen

PEMprotonexchangemembrane

PVphotovoltaic

SDG

SustainableDevelopmentGoals

SMR

steammethanereforming

SOEC

solidoxideelectrolysercells

Unitsofmeasure

GWgigawatt

kgkilogram

ktkilotonne

Llitre

m3cubicmetre

Mtmegatonne

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Glossary

Blowdownwater:Waterdrainedintentionallyfromcoolingsystemstopreventmineralbuild-up.

Cycleofconcentration:Ameasureofthebuild-upofdissolvedmineralsincoolingsystems.Thecycleiscalculatedbycomparingtheconcentrationofaparticulardissolvedsolidinthewatercomingoutofacoolingsystemtoitsconcentrationinthewaterflowingintothesystem.

Deionisedwater:Atypeofhighlypurifiedwaterthatdoesnotcontainanyatoms,ionsormolecules.Deionisationremovesdissolvedsubstanceslikesodiumchloride,minerals,carbondioxide,organicpollutantsandvariousothercontaminantsfromwater.

Makeupwater:Thewateraddedbackintoacoolingsystemtoreplacewaterlostduetoevaporation,leaks,etc.

Permeaterate:Inmembrane-basedwatertreatmentsystems,theratioofthevolumeofwaterpassingthroughthemembranetothetotalquantityofrawwater.

Waterwithdrawal:Measuredbythequantityofwaterwithdrawnfromasource(e.g.river,lake,groundwater)foruse.

Waterwithdrawal/consumptionintensity:Thequantityofwaterwithdrawnfororconsumedinthegenerationofaunitofaproduct(e.g.amegawatthourofenergy,amegatonneofhydrogen).

Waterconsumption:Theportionofwithdrawnwaterthatisnotreturnedtothesource.

Waterstress:Measuredusingtheratioofthetotalwaterwithdrawaltotheavailablerenewablefreshwatersupply.Itshouldbecalculatedatawatershedscale.Waterstressposessignificantriskstohumanandenvironmentalwell-beingandisaproxyforwatercompetitionamongsectorsanduses.

EXECUTIVESUMMARY

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Executivesummary

Theenergysectoristhelargestwateruserofallindustrialsectors.Waterisrequiredinmanyofitsprocesses,fromfuelextractiontoelectricitygeneration.AsseenintherecentnuclearpowerplantshutdownsinEuropein2022,watershortagescansignificantlydisruptthesector.Andthedisruptionsarelikelytocontinueandtobecomeevenmorefrequent,especiallyasextremeweathereventsintensifyamidachangingclimate.Toaddresstherisingclimaterisks,theenergysectorisalreadyestablishinggoodpracticesforintegratingwaterconsiderationsintoplanning.Thesectorcanmitigateitswaterrisksbytransitioningtorenewableenergysources,whichconsumelesswaterthantraditionalfossilfuels.

Cleanhydrogenhasemergedasaviablealternativeinthefightagainstclimatechange.Hydrogenisagamechanger,especiallyfor“hardtoabate”,suchassteelmaking,chemicalproduction,aviation,shippingandtrucktransport.Assessingthewateruseimplicationsofhydrogenproduction,especiallyinwater-stressedareas,isessentialinmanagingpotentialdisruptionstoproduction.

Allhydrogenproductiontechnologiesrequirewaterasaninput.Waterisneedednotonlyinproductionbutalsoforcooling.Thewithdrawalandconsumptionofwaterforcleanhydrogenproductionhavebeendebated,yettoooftenthediscussionsarenotinformedbyin-depthknowledgeofthesestill-nascenttechnologies.

Thisreport,compiledbytheInternationalRenewableEnergyAgency(IRENA)andBluerisk,seekstoanswersomeofthesequestions.

Howmuchwaterdoesahydrogenplantactuallyconsume?

Thisreportreviewsthewaterwithdrawalandconsumptionrequirementsofvarioushydrogenproductiontechnologiesindetail.Datahavebeensourcedfrominterviewswithindustryexpertsandareviewofexistingliterature,sheddinglightonthewaterimplicationsofscalingupcleanhydrogenproduction.AveragewaterwithdrawalandconsumptionintensityandrangesarevisualisedinFigureS1.

Greenhydrogenisthemostwaterefficientofallcleanhydrogentypes.Itisfoundthatonaverage,protonexchangemembrane(PEM)electrolysishasthelowestwaterconsumptionintensityatabout17.5litresperkilogrammeofhydrogen(L/kg).AlkalineelectrolysisfollowsPEMelectrolysis,withawaterconsumptionintensityof22.3L/kg.Thesemaybecomparedwithsteammethanereforming–carboncapture,utilisationandstorage(SMR-CCUS),at32.2L/kg,andautothermalreforming(ATR)-CCUSat24.2L/kg.

WATERFORHYDROGENPRODUCTION

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FIGURES1Acomparisonofaveragewaterwithdrawalandconsumptionintensitiesbyhydrogenproductiontechnology

Averagewaterintensity(L/kg)

Coalgasi?cation

49.8

31.0

Naturalgas-SMR

20.0

17.5

Coalgasi?cation-CCUS

80.2

49.4

Naturalgas-SMR-CCUS

36.732.2

Naturalgas-ATR-CCUS

30.824.2

Electrolysis-Alkaline

32.2

22.3

Electrolysis-PEM

25.717.5

WithdrawalConsumption

Note:Tapwater(orsourceswithsimilarwaterquality)is(are)usedorassumedtobethewatersource(s)behindthesedatapoints.Forbluehydrogen,thecoolingrequirementsforCCUSsystemsareincluded.ForPEMandATR,availabledatapointsarelimitedsincethesetechnologiesarerelativelynew–thusthemuchsmallerrangesofvalues.ATR=autothermalreforming;CCUS=carboncapture,utilisationandstorage;kg=kilogramme;L=litre;PEM=protonexchangemembrane;SMR=steammethanereforming.

Coalgasificationisbyfarthemostwaterintensiveofavailabletechnologies;itwouldbeabout60%moreintensiveifequippedwithCCUS.Coalgasificationhasawaterwithdrawalrequirementofabout50L/kgandconsumes31L/kg,onaverage–roughlytwicePEM’swaterwithdrawalandconsumptionrequirements.EquippedwithCCUS,coalgasification’swithdrawalaswellasconsumptionrequirementscould furtherincreaseto80.2and49.4L/kg,respectively.Acoalgasificationhydrogenplantproducing237kilotonnes(kt)ofhydrogenperyearandequippedwithCCUSwouldwithdrawabout19millioncubicmetres(m3)ofwaterannually;thisvolumeofwatercouldsupporthalfthewaterdemandofthecityofLondonforanentireyear.

EXECUTIVESUMMARY

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Waterisrequiredasaninputforproductionandasacoolingmediumforalltypesofhydrogenproduction.Dependingonthetechnology,theshareofwithdrawalforcoolingcanrangefrom14%to92%.Theshareofwaterwithdrawalforcoolingisthelowestforgreyhydrogenproduction,atabout14%.Greenandbrownhydrogen’ssharesare56%and52%,respectively.Bluehydrogenproductionrequiresmorewaterforcooling,duetothesignificantwaterrequirementsofCCUSsystemsforheattransfer.Coolingcanaccountforupto92%ofthetotalwithdrawalrequirementofbluehydrogen,accordingtodatafromtheNationalEnergyTechnologyLaboratoryintheUnitedStates.However,moreevidenceisneededbeforeageneralproduction-coolingratiocanbedeterminedwithoutdispute.

Forevery1percentagepointincreaseinelectrolysisefficiency,thewaterwithdrawalaswellasconsumptionrequirementsofgreenhydrogenproductionlessenbyabout2%.Thisisprimarilybecause,forthesametypeofhydrogenproductiontechnology,themoreenergyefficientthesystemis,thelesswasteheatneedstobetransferred;thismeanslesswaterisrequiredforcooling.

Whatwillbetheglobalimpactofcleanhydrogen?

Thisreportpresentsacomprehensiveanalysisofthewaterfootprintandrisksassociatedwithcurrentandprojectedfutureglobalhydrogenproduction.TheanalysisisbasedonIRENA’s1.5°CScenario,whichprojectssubstantialgrowthinhydrogenproductionby2050.

WATERFORHYDROGENPRODUCTION

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Annualfreshwaterwithdrawal

(billionm3)

Today,about2.2billionm3offreshwateriswithdrawnforglobalhydrogenproductioneveryyear;thisaccountsfor0.6%oftheenergysector’stotalfreshwaterwithdrawal.AsillustratedinFigureS2,greyhydrogenproductionaccountsforabout59%oftheglobalfreshwaterwithdrawalforhydrogenproduction,brownhydrogen40%,andtherestisfromgreenandbluehydrogen.

Freshwaterwithdrawalsforglobalhydrogenproductioncouldmorethantripleby2040andincreasesix-foldby2050,comparedwithtoday.Drivenbythesignificantexpansionofglobaldemandforhydrogen,thetotalfreshwaterwithdrawalrequiredbyglobalhydrogenproductionisprojectedtobeabout7.3billionm3by2040and12.1billionm3by2050,factoringintechnologyadvancements.Hydrogenproduction’sshareoftotalfreshwaterwithdrawnfortheenergysectorcouldrisefrom0.6%todayto2.4%by2040.

FIGURES2Currentandprojectedfreshwaterwithdrawalforglobalhydrogenproduction,bypathway

14

11

7

4

0

12.1

0.6

7.3

3.2

11.5

2.2

1.3

0.9

4.1

2050

2040

Current

BrownH2GreyH2BlueH2GreenH2

Note:Tapwater(orwatersourceswithsimilarwaterquality)is(are)assumedtobethewatersource(s).Projecteddesalination-basedandseawater-cooledhydrogenproduction(e.g.intheGCCcountries)isexcluded.BlueH2includesSMR-CCUS,ATR-CCUSandcoal-CCUS,withtheshareofATR-CCUSassumedtograduallyincreaseto75%by2050.CoolinginblueH2productionincludesthecoolingdemandduetoCCUSsystems.GreenH2includesbothalkalineandPEMelectrolysiswiththeshareofPEMelectrolysisassumedtograduallyincreaseto75%by2050.Moderategradualincreasesinelectrolysisefficiency(7.5percentagepointsforalkalineelectrolysisand4.5percentagepointsforPEM-electrolysisoverthecomingthreedecades)areassumed.Forcalculationpurposes,thecoolingandproductionsharesofblueH2inCase2fromLewisetal.(2022)areapplied.ATR=autothermalreforming;CCUS=carboncapture,utilisationandstorage;H2=hydrogen;PEM=protonexchangemembrane;SMR=steammethanereforming.

EXECUTIVESUMMARY

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Andthelocalimpact?

Althoughthewaterconsumedforhydrogenproductionwillnothaveasignificantimpactglobally,theimportanceofconsideringlocalwatercontextswhenplanninghydrogendevelopmentcannotbeoverstated,especiallychronicwaterriskssuchaswaterstress.

Morethan35%oftheglobalgreenandbluehydrogenproductioncapacity(inoperationandplanned)islocatedinhighlywater-stressedregions.UsingtheAqueductWaterRiskAtlas,thisreportassesseswaterstressconditionsinlocationswhereglobalgreenandbluehydrogenprojectsarealreadyoperatingorbeingplanned.KeyregionalfindingsrevealthatIndiaislikelytohave99%ofitshydrogencapacityinextremelywater-stressedareasby2040,whileChinaandtheEU-27alsofacesignificantwaterstresschallenges.TheUnitedStatesandotherGroupofTwenty(G20)countriesareexposedtowaterstresstovaryingdegrees.Hydrogenproductionunderwaterstressconditionswouldfacefrequentdisruption,besidesbeingexposedtotheriskofuncertaintiessurroundingenvironmentalregulations.

Thereportpresentsin-depthanalysesofthewaterchallengesfacedbythehydrogenproductionindustryinNorthernChina,theGulfCooperationCouncil(GCC)countriesandEurope.

WATERFORHYDROGENPRODUCTION

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NorthernChina

CoalchemicalplantsinnorthernChinacontributesignificantlytothecountry’scurrenthydrogenproduction,buttheyrequirelargeamountsoffreshwatertooperate.Forexample,freshwaterwithdrawalsforhydrogenproductionintheprovinceofShanxiareestimatedtoaccountforover30%oftheprovince’soverallindustrialwaterwithdrawal.Mostofthesecoal-firedchemicalplantsarelocatedintheYellowRiverBasin,aregionwherewaterisextremelyscarce.Over70%oftheseplantsoperateinareasunderseverewaterstress,makingthemvulnerabletofluctuationsinwateravailabilityandchangingregulations.

Continuousexpansionofthehydrogenindustryisprojectedtodriveupwaterdemandsignificantlyby2030ifcoal-basedproductioncontinuestodominate.Thiswouldbringtheregion’swaterresourcesunderevenmorestress.Atransitiontoalternativetechnologiessuchasalkalineelectrolysisbecomescrucialtosustainablyaddressthesechallengessincethesetechnologiescanhelpmeetfuturedemandforhydrogen,whilereducingfreshwaterwithdrawalandconsumptiontolevelsevenbelowthoseseentoday.Alternativetechnologiesarethuspromisingsolutionstowater-relatedconcerns.

GulfCooperationCouncil

IntheGCCcountries,thepursuitofhydrogenproductionpresentsuniquechallengesandopportunities.Thesecountriesaremajorproducersofgreyhydrogenfromnaturalgasandofferscopeforatransitiontogreenhydrogenproduction.However,waterscarcityisasignificantissueintheGCCcountries,whichrelyheavilyondesalinatedwaterforhydrogenproductionandemployonce-throughcoolingsystems,raisingbothenvironmentalandeconomicconcerns,includingthermalandbrinepollutionandhighenergycosts.

Astheregionaimstoproducemorehydrogenby2040,atriplingofseawaterwithdrawalisprojected.Thisunderlinesanurgentneedforsustainablewatermanagementpractices.AtransitiontoalternativeproductiontechnologiessuchasalkalineandPEMelectrolysiscaneffectivelyreduceseawaterwithdrawalandthedemandfordesalinatedwater,addressingthesechallengeswhilemakingthehydrogenproductionindustrymoresustainableandresponsible.

Europe

ThepursuitofgreenhydrogeninEuropeispivotaltotheregion’sambitiousemissionmitigationgoals.However,Europefacesuniquechallenges,notablyincreasedoccurrencesofdroughts,whichimpactenergyproductionandexacerbatewaterstress.EventhoughEurope’shydrogenconsumptionisrelativelylowtoday,theregionhasarapidlygrowinghydrogenindustry,whichhasprojectslocatedacrossthecontinent,manynearcoastlinesandmajorrivers.Importantly,over23%ofEurope’sgreenhydrogenprojectsand14%ofitsbluehydrogenprojectsarelikelytobeinareasunderhighorextremelyhighwaterstressby2040,potentiallyincreasingthecompetitionforlocalwateruse.

AsEuropeshiftsitshydrogenproductionmix,thewaterdemandisexpectedtoincreasesignificantlyby2040.Thiswillplacenewpressuresonwaterresourcesinwater-stressedregions.Toensureasustainableandenvironmentallyresponsiblehydrogenindustry,Europemustintegratewaterconsiderationsintoitsenergyplanninganddevelopmentdecisionmaking.Itmustcarefullymanagewatercompetitionandpromotewater-efficienttechnologiessuchasPEM-basedelectrolysis.

EXECUTIVESUMMARY

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So,whatshouldwedo?

Thereportendswithasetofrecommendations,basedontheresultsoftheanalysis.Theserecommendationsaredesignedtoreducetheexposureoffuturecleanhydrogenprojectstowater-shortage-relatedrisks.

→Greenhydrogenprojectsshouldbeprioritisedforfuturehydrogendevelopment.

→Water-relatedimpactsandpotentialrisksneedtobecarefullyevaluatedinhydrogenproductiondevelopmentplans,particularlyinwater-stressedregionswherestringentwateruseregulationsmustbeestablishedforthesector,andenforced.

→Retiringfossil-fuel-basedhydrogenplantsandreplacingthemwithgreenhydrogenshouldbeprioritisedinhydrogendevelopmentplans,particularlyinareaswhere

waterisalreadyscarce.

→Waterwithdrawalandconsumptionshouldbeconsideredasperformanceindicatorsofhydrogenproductionprojectsforpre-operationalevaluationpurposesandbe

meteredandmonitoredduringoperation.

→Regulationsandfinancialincentivesshouldfavourprojectsdemonstratinghigherefficiencyinenergyconversionandwaterconsumption.

→Moreinvestmentandresearcharerequiredtoimprovetheefficiencyofcommercial-scaleelectrolysersandreducetheconsumptionoffreshwaterforcooling.

→Hydrogenproductionprojectsinregionswherewaterisalreadyscarceshouldbeincentivisedtousewater-efficientcoolingtechnologiessuchasaircooling.

→Inpresentandfuturefreshwater-stressedcoastalareas,utilisingseawaterforhydrogenproductionandcoolingprocessesshouldbeincentivised,evenasregulationsforthermalpollutionandbrinemanagementareenforced.

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WATERFORHYDROGENPRODUCTION

CHAPTER1:INTRODUCTIONTOTHEHYDROGEN-WATERNEXUS

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Chapter1:Introductiontothe

hydrogen-waternexus

In2015,partiestotheParisAgreementconcurredthaturgentactiontodecarbonisetheirnationaleconomiesisnecessarytomitigatetheharmfuleffectsofclimatechange.Later,in2018,theIntergovernmentalPanelonClimateChangereleasedthereport“GlobalWarmingof1.5°C”,whichcalledforpolicymakerstointensifyandaccelerateeffortstomitigategreenhousegas(GHG)emissions,limittheglobaltemperatureriseandaddresstheclimatecrisis(IPCC,2018).

Accordingtothereport,thereisanarrowwindowofopportunitytoenactmeaningfulmeasurestopreventfurthertemperatureincreaseandaddresstheclimatecrisis.PolicymakersmustthereforestrengtheneffortstoreduceGHGemissionsfromalleconomicactivitiesasmuchaspossible.Solutionsthatreduceonlyasmallportionofemissionsareinadequate;itisnowcriticaltoprioritiseoptionsthatcanprovidesignificantemissionreductions.

Meanwhile,certainindustryandtransportsubsectorsareparticularlydifficulttodecarbonise,frombothatechnicalandeconomicperspective,andcorrespondingsolutionsarelimitedinnumber.Thesesectors,knownas“hard-to-abate”sectors,includesteelmaking,basicchemicalproduction,long-haulaviation,shippingandtrucktransport.

WATERFORHYDROGENPRODUCTION

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Enterhydrogen,themostabundantchemicalintheuniverse.Around95megatonnes(Mt)ofhydrogenwereproducedfromfossilfuelsin2022–forrefineries,theproductionofbasicchemicalsandafewotheruses(IEA,2023).

Hydrogencanbeusedasafeedstock-toproducesteel,ammonia,methanol,fertilisersandsyntheticfuel,andtopowervehicles-orstored,fortimeswhenrenewablesareataseasonallow.TheInternationalRenewableEnergyAg