ALLIANCE

AnATISInitiative

NextGAllianceReport:

EvolutionofSustainabilityIndicatorsforDataCentersand

NextGenerationCoreNetworks

2

Asaleadingtechnologyandsolutionsdevelopmentorganization,theAllianceforTelecommunicationsIndustrySolutions(ATIS)bringstogetherthetop

FOREWORD

globalInformationCommunicationsTechnology(ICT)companiestoadvancetheindustry’sbusinesspriorities.ATIS’150membercompaniesarecurrentlyworkingtoaddressnetworkreliability,5G,robocallmitigation,smartcities,

artificialintelligence(AI)-enablednetworks,distributedledger/blockchaintechnology,cybersecurity,IoT,emergencyservices,qualityofservice,

billingsupport,operationsandmuchmore.Theseprioritiesfollowafast-trackdevelopmentlifecyclefromdesignandinnovationthroughstandards,specifications,requirements,businessusecases,softwaretoolkits,open-sourcesolutions,andinteroperabilitytesting.

ATISisaccreditedbytheAmericanNationalStandardsInstitute

(ANSI).ATISistheNorthAmericanOrganizationalPartnerforthe3rd

GenerationPartnershipProject(3GPP),amemberoftheInternational

TelecommunicationUnion(ITU),aswellasamemberoftheInter-AmericanTelecommunicationCommission(CITEL).

Formoreinformation,visit.FollowATISonTwitterandonLinkedIn.

TheATIS‘NextGAlliance’isaninitiativetoadvanceNorthAmericanwirelesstechnologyleadershipoverthenextdecadethroughprivate-sector-ledefforts.Withastrongemphasisontechnologycommercialization,theworkwill

encompassthefulllifecycleofresearchanddevelopment,manufacturing,standardization,andmarketreadiness.

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EXECUTIVESUMMARY

Withthegrowingdemandfor5Gandtheadventof6G,theICTIndustryhasanopportunitytoachievenet-zerooperationsintheforeseeablefutureby

implementingacomprehensivelifecy-cleapproach.Thisincludesthedesign,build,operationsandmaintenanceandultimatelythedecommissioningofmobilenetworkresources.CorenetworksandothermobileNetworkFunc-tions(NFs)deployedindatacentersarereplacingtraditionaldedicated

hardwareimplementa-tions.Thispaperprovidesmultipleperspectiveson

howobservability,theuseofcircularecon-omyprincipals,andchoicepavethewayfororganizationstoembarkontheirsustainabilityjourney,ultimatelyreachingnet-zerooperations.

Theincreasingdemandfordigitizationprocessesandfunctionshasled

toariseinenergyre-quirementstopowertheseapplications.Consideringsustainability,softwareapplicationsmustbeoptimizedtoefficientlyuseITassets,whichresideindatacentersofvariouskinds.Thesedatacenters

canbecloudandon-premise,includingCentralOffices,assets.Regardlessofthedatacenterassetclass,itrequirescarefulconsiderationofthedesign,building,andoperationofthephysicalinfrastructuresupportingthese

datacenters.TheITassetsandtheinfrastruc-tureitselfconsumeenergy

andotherresourcesthatneedcontinuousimprovement.Theevolu-tionof

sustainabilityindicatorsfordatacentersandnextgenerationcorenetworksbecomesmorerelevant.ItincludesacomprehensivelookatexistingandnewKeyPerformanceIndica-tors(KPI)allowingdatacenterandcorenetwork

operatorstomeasureandimprovetheircur-rentandfutureuseofpreciousresources.

TraditionalKPIs,suchasPowerUtilizationEffectiveness(PUE)measurea

datacenter’soverallenergyconsumptionrelativetotheenergyusedforITassets.Whilefundamentallyeffective,thissimplemetricfailstoconsider

otherimportantaspectsbeyondenergyusage.GreenhouseGas(GHG)

emissionsassociatedwiththeproductionofcomponentsandbuildings,

watercon-servationmeasures,wastereductionandelimination,andthe

overallimpactonthelocaleco-systemallneedtobeconsideredinthe

networkoperators’sustainabilityjourney.Afreshlookonprocuringenergy,equipment,andmaterialsfromsustainableandethicalsourcesisbecom-ingessential.

SustainabilityhasreacheddifferentlevelsofmaturitythroughouttheICT

industry.Thispapernotonlyoutlinestheimportance,butalsoservesasa

guidetofurthereducate,evaluate,andimplementaholisticsustainability

approach.Finally,practicalrecommendationssuchasthedevelopmentofanorganization’ssustainabilitystrategyandidentifyingandimplementingrel-

evantandfutureKPIsaremade.

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TABLE OFCONTENTS

Foreword2

ExecutiveSummary

3

1Introduction5

2EnhancedApproachtoEnvironmentalSustainabilityIndicatorsfor6G

6

2.1Observability

6

2.2Choice

6

2.3CircularEconomy

6

36GApplicationsRunningonITAssets

7

3.1WorkloadRequirementsIncludingEnergyConsumption

7

3.2ExistingKPIs(Compute/Energy)

8

3.3CurrentLimitationsandRelevancetotheDataCenterKPIs

8

4ITAssets-Compute,Network,Storage

10

4.1GuidelinesforaSustainableComputeEnvironment

10

4.2ExampleofScope3Evaluation

11

5DataCenters

13

5.1KeyTrendsinDataCenters

13

5.2TypesofDataCenters

13

5.2.1HyperscaleDataCenters

13

5.2.2CentralOfficeandOn-Premise

14

5.2.3EdgeDeployments

14

5.2.4ApplicationServer

15

5.3DataCenterArchitecture,Redundancy,

15

AvailabilityandImpactonSustainability

5.4CurrentDataCenterSustainabilityKPIsandtheirImpact

16

5.4.1SustainabilityAttributesforDataCenters

16

5.4.2EnergyEfficiency

16

PowerUsageEffectiveness(PUE)

16

RenewableEnergyFactor(REF)

17

EnergyReuseFactor(ERF)

17

WaterUsageEffectiveness(WUE)

17

5.4.3AdditionalKPIs

19

6SummaryandRecommendations

20

7Abbreviations

21

8References

23

Acknowledgments

25

NextGAllianceReports

28

CopyrightandDisclaimer

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5

1INTRODUCTION

Addressingclimatechangeisthebiggestchallengefacedbyhumanityandtoavoidtheworstenvironmentalimpactsofclimatechange,weneedtolimitlongtermglobalwarmingbelow1.5Cfrompre-industriallevels.However,accordingtotheUnitedNation(UN)humanityiscurrentlynotontracktoachievethisobjective[1].

TheInformationCommunicationTechnology(ICT)ecosystemhasestablishedacollaborativeframeworkaimedatachievingnetzeroemissionsby2050atthelatest.Thispathway

tonetzerospanstheentireICTvaluechain,addressing

emissionsunderdirectoperationalcontrol(Scope1),

indirectemissionsfrompurchasedelectricity(Scope2),andemissionsassociatedwithproductsduringmanufacturingandtransportation(Scope3).

Thiswhitepaperprovidesanoverviewofkeydatacenter

sustainabilitystrategiesthatarecriticalforachievingNet

ZeroemissionsacrosstheentireICTvaluechain.Recent

GlobalSystemforMobileCommunicationsAssociation

(GSMA)reportindicatesthatthecorenetworkwhichhandlescentralizednetworkfunctionsandthedatacenteronwhichitcanoperateconsumesaround19%oftotalenergyintheoperationofmobilenetworks[2].Asmorecorenetwork

serviceshavemovedintothecloudin5G,datacenterpowerconsumptionhasincreased.

Additionally,accordingtotheInternationalEnergyAgencyelectricityconsumptionfromdatacenters,AIandthe

cryptocurrencysectorcoulddoubleby2026comparedto

2022,reachingmorethan1,000TWhin2026[3].Making

sustainableoperationsofdatacenterscriticalfortheICT

sector’sgoaltoachieveNetZeroemissions.Focusing

onthedatacenterdomainandcoveringcloudenterprise

andedgedatacentersofallsizes,thiswhitepaperoffers

recommendationforbenchmarkingthecarbonfootprint

andotherkeyenvironmentalsustainabilityKeyPerformanceIndicators(KPIs).

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2SEUNSAAIIIFNVIRONMENTAL

Theexisting5GnetworkKPIsprimarilyemphasize

observabilitytogaugeperformanceandresultswithverycoarsegranularity.However,theadventof6Gnecessitatesacomprehensiveparadigmshift.AsFigure1illustrates,

itencompassesthreecrucialdimensionsintermsofimplementingenvironmentalsustainabilityKPImetrics:

Observability,Choice,andCircularEconomy(OCC)[4].

objectives.Nearreal-timedashboardsprovideupdatesabouttheenvironmentalimpactofvariousserviceconfigurations,offeringchoicestomakeinformeddecisionsbasedon

sustainabilitypreferences.Thisfosterscollaborationin

decision-makingregardingarchitecturaldesign,resource

ExampleKPI:SustainabilityImpactIndex

Definition:Acompositeindex

thatdynamicallyquantifiesthe

environmentalimpactofdata

centerandcorenetworkoperations,includingenergyconsumption,

carbonemissions,andresourceutilization,allowingnetwork

architectstomakeinformed

decisionsbasedondatagatheredoveracertainperiodoftime(e.g.,monthly).

ExampleKPI:GreenServicePerformanceIndex

Definition:Acompositeindex

thatfactorsinbothtraditional

performancemetrics(e.g.,data

allocation,andoperationalpractices.BelowisanexampleoftheKPIthathelpstomakethoseinformeddecisions.

ca

Observability

Allowstotrackandreportenvironmental

indicatorsandenableschoicebyinforming

highlevelsofsteerabilityandversatileactions

CircularEconomy

Ensuresnear-zerowastethroughhighdegreesofreuseandrecyclingofrenewableorrecovered

components,rawandrarematerials,andproducts

Empowerstheentirevaluechain,fromstandardsandproductdeveloperstooperatorsandusers,toexercisepreferencesthatimpactsustainability

Choice

Figure1:6GEnhanceEnvironmentalSustainabilityKPIs

speed,latency)andsustainabilitymetrics(e.g.,energyefficiency,PUE,

2.1

Observability

Observabilityinthedatacenterandcorenetworkenables

nearreal-timerecordingandreportingofKPImetrics,whicharecrucialthroughoutthetechnologicallifecycle.Thisis

essentialforassessingtheenvironmentalimpactof6G

technologies,bothduringthedesignandoperationofdatacentertechnologies.Nearreal-timereportingmechanismsindatacentersallowformonitoringoftheentireinfrastructure,checkingapplicationperformanceandenergyconsumption,andincreasingefficiencyinfuturecapacityplanningby

analyzingresourceutilizationtrends.Similarly,observabilityinthecorenetworkaidsintrafficanalysisandnetwork

optimization.Overall,observabilitycontributestoadvancingtheentireecosystemtowardsamoreenvironmentally

sustainablefuture.

2.2

Choice

Theconceptofchoiceempowersdatacenterandcorenetworkoperators,productdevelopers,usersaswellasnetworkarchitects,tonavigatealandscapewheresustainabilitygoalsalignseamlesslywithperformance

wastefactor[5]toprovideaholisticviewofservicequalityindatacenterandcorenetworkoperations.

2.3

CircularEconomy

CircularEconomyisthedeparturefromlineareconomic

modelsasitisrestorativeandregenerativeinnatureandtheaimistokeepcomponentsandmaterialsattheirhighest

utilityandvalueatalltimeswhilereducingthewastestreams.Thedatacenterandtherestofthenetworkinfrastructure

consistofequipmentsuchasservers,storageunits,

networkingdevices,andcoolingsystems.Asbusinesses

andservicestransitiontowardhigher-performingandmoreenergy-efficientequipment,extendingthelifetimeofdata

centerequipmentbecomescrucial.Circulareconomy

principlesadvocateforconsideringlifecyclefactors,

includingdurability,upgradability,repairability,reusability,

refurbishability,andrecyclabilityorrecoverabilityatend-of-

life,evenduringthedesignphase.It’sessentialtoensure

thattheproductionprocessitselfissustainable,minimizingenvironmentalimpactthroughtheuseofrenewablematerialsandenergysources.

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36GAPPLICATIONSRUNNINGONITASSETS

3.1

WorkloadRequirementsIncludingEnergyConsumption

6Goperatornetworks,providingservicesincluding

connectivitybetweenaUEandapplicationsresidinginadatanetwork(DN)areexpectedtocontinuetheevolutionstartedin5Gfromrequiringnetworkfunctionsrealizedonbespoke,dedicatedhardwarewithspecializedplatformresources

toutilizingvirtualizedcloudnativenetworkfunctionsthat

maybeinstantiatedandmanagedasworkloadsrunningondatacenterresources.5Gpresentedthefirststageofthis

evolutionwiththeintroductionofaservice-basedarchitectureandtheexplicitspecificationthat5GCuserplaneandcontrolplanenetworkfunctions(i.e.,AMF,SMF,PCF,NWDAF,NSSF,NEF,NRF,UPF,etc.)maybevirtualizedandinstantiatedon

anappropriateplatform,e.g.,oncloudinfrastructure[6]

ratherthanimplementedassoftwarerunningonadedicatedhardware.Supportedvirtualizeddeploymentsinclude:

>NetworkFunctioninstancescomprisedofoneormoreserviceswithconstituentserviceoperations,thatmaybedeployedasdistributed,redundant,stateless,andscalablenetworkfunctioninstances.Servicesmaybeprovidedfrommultiplelocationswithseveralexecutioninstancesineachlocation.

>NetworkFunctioninstancesdeployedsuchthat

severalnetworkfunctioninstancesarepresentwithinanetworkfunctionsetthathaveaccesstocommon,sharedstateinformation.Networkfunctionsinstanceswithinanetworkfunctionsetcanbeselected

interchangeablytoenabledistributed,redundant,statelessandscalablefunctionality[6].

Increasingly,adisaggregatedvirtualizedRadioAccess

Network(RAN),especiallycentralizedcontrolplaneaspectswhichdonotrequirespecializedprocessingcapabilities

(e.g.,the5GCU-CP)willfollowthecorenetworkinbecomingdatacenterapplicationworkloadsthatrunonITassets.

Themotivationforthisisthewellunderstoodbenefitsofvirtualization,whichincludesreliability,scalability,life-cyclemanagement,interoperability,costandtheabilitytodynamicallyinstantiatefunctionsaccordingtouserrequirementsandtrafficdemand.

Theevolutionfromdedicatedhardwaretoedgeand

centralizeddatacenterhostedcomputeresourcesfor5G

and6Gfunctionsgreatlyfacilitatesselectionofnetwork

functioninstancesaccordingtouserrequirements.Those

requirementsmaybesatisfiedinanumberofways.For

example,anetworksliceorprivatenetworkthatcomprisesdedicatedVirtualizedNetworkFunction(VNF)instancesmaybeused.SliceornetworkspecificKPIsassociatedwitha

standardizedoroperatorspecificServiceTypecharacterize

bothperformanceandsustainability,wheretheServiceTypesmayincludethosedefinedby3GPPfornetworkslices:

Slice/Servicetype

Description

eMBB

5GenhancedMobileBroadband

URLLC

Ultra-reliablelowlatencycommunications

MIoT

MassiveInternetofThings(IoT)

V2X

V2Xservices

HMTC

High-PerformanceMachine-TypeCommunications

HDLLC

HighDatarateandLowLatencyCommunications

Table1:StandardizedSSTValues[6]

Forsustainability,forexample,anetworkslicetosupport

MIoTmaybecomprisedofnetworkfunctionsinstantiatedinacentralizeddatacenterwhereaprevailingefficiencymetricsuchastheenergyconsumptionperregisteredMIoTuser

maybebetteroptimized.HeretheenergyconsumptionisthatconsumedbytheVNFsintheMIoTnetworkslice.Incontrastanetworkslicetosupportmobilebroadbandservice(eMBB)maybecomposedofnetworkfunctionsinstantiatedin

centralizedoredgedatacenters,andtheefficiencymetricofinterestisenergyconsumedperkbpsthroughput.

Sustainabilitymaybeusedbyoperatorstolowercosts,oritmaybeofferedasaservicetosubscribersandoptionallymonetized.Inbothexamplesabove(MIoTandeMBB),

sustainabilitymaybeanetworksliceattribute,andslicesforagivenservicetypemaybecreatedbyanetworkoperatortosupportsustainabilitytrade-offs.Forexample,anetworkoperatorcouldofferconsumersachoiceofservicewith:

>aneMBBnetworkslice,withhighsustainability,butatahigherpriceorlowerdatarateorlowerreliability

>aneMBBnetworkslice,withlowersustainability,butatalowercostorahigherdatarateorhigherreliability

>anMIoTnetworkslice,withhighsustainability,butatahigherpriceorlowerdatarate,etc.

>anMioTnetworkslice,withlowersustainabilityatalowercostorhigherdatarate,etc.

In6G,sustainabilityasasubscriberserviceisexpected

tobecomefurtherintegratedwiththenetwork.Thismay

berealizedbyprovidingsustainabilityasanattributeofa

networksliceusedbysubscribers,orasaservicetoindividualsubscribers,similartohowQualityofService(QoS)is

currentlyprovided.Specifically,inthe5GS,subscriberservice

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allowsdifferentiatedQoSandcharging.Thisistypically

enabledviaaPolicyControlFunction(PCF)thatdeterminesonaper-subscriber,perapplicationbasistheparametersofservice(i.e.,chargingrateand5GSQoSattributessuchaslatency,guaranteedbitrate,etc.).NetworkfunctionselectionmaybeaffectedbytherequirementtomeetQoSattributes.Forexample,forultra-lowlatencycommunication,aPowerDistributionUnit(PDU)SessionAnchor(PSA)UPFnetwork

functionatanedgeorenterprisedatacentermaybeselected

ratherthanaPSAUPFatacentrallylocateddatacenter.Thisshortensthedistanceandnumberofnetworkhopsforprovidingconnectivityinalocalenvironmentsuchasafactory.

Similarfunctionalitymaybeextendedin6Gtoprovide

sustainabilityasaservice.In5GAdvanced,3GPPisalreadystudying[7]howsubscriptionandpolicycontrolcanbe

enhancedtosupportenergyefficiencyandenergysavingasaservice.Furthermore,InternetEngineeringTaskForce(IETF)Computing-AwareTrafficSteering(CATS)workinggroupand3GPPEdgeComputing[8]aredetermininghownetworking

andcomputeresourcesmaybecoordinated.Thateffortmayinvolveselectingauserapplicationinstanceincoordinationwithmobilitynetworkanchor(i.e.,PSAUPFNF)onadata

centercomputenodethatisascloseaspossibletotheUEandwherecomputeresourcesareavailable.Doingsowithsustainabilitymetricsinmindisalogicalextensionofthatcapability(i.e.,selectingboththeuserapplicationinstanceandthePSAUPFnetworkfunctionconsideringdatacentersustainabilityaswellascomputeandnetworkresources).

TheemergingabilitytoselectcomputeresourcesaccordingtosustainabilityrequirementsleadstoaninterrelationshipbetweennetworkKPIsusedbynetworkoperatorsto

assesssustainabilityandKPIsusedtoassessdatacentersustainability.

3.2

ExistingKPIs(Compute/Energy)

5GSsustainabilityKPIs,forexamplethosedefinedby3GPPin“5GEndtoEndKPIs”[9]and“ManagementandOrchestration;EnergyEfficiencyof5G”[10]focusonenergyconsumption

andenergyefficiencyratherthanoverallsustainability.VNFresidingasapplicationworkloadsindatacentersarean

importantcomponentinthetotalenergyandsustainabilitypicture,thoughothercomponents,particularlyradioandtransportnetworksarethebiggestenergyconsumers

andalsohavethebiggestimpactonoverallsustainability.Relevant3GPPdefinedKPIsfordiscussioninthispaperinclude:

>NetworkSliceEnergyEfficiency=NetworkSlice

Performance/SliceEnergyConsumption,where

thesliceperformancemetricvariesaccordingto

thetypeofnetworkslice.Forexample,foreMBBthe

performancemaybebasedondatavolume,forURLLCtheperformancemaybebasedonacombinationtheexperiencednetworklatencyandthedatavolume

andforMIoTitmaybebasedonthenumberof

registeredsubscribersornumberofactiveMIoTUEs.Aportionofthenetworksliceenergyefficiencymaybe

attributedtoVNFworkloadsresidingindatacenters.Forthiscomponent,acorrespondingNetworkSliceEnergyefficiencymaybebasedontheSliceEnergyConsumptionoftheVNF.

>EnergyConsumptionofVNFscanbeapproximatedfromtheestimatedenergyconsumptionofits

constituentVirtualizedNetworkFunctionComponents(VNFCs).ThelatterisdeterminedfromtheestimatedenergyconsumptionofthevirtualcomputeresourceinstancesonwhichaVNFCruns.Theenergy

consumptionofavirtualcomputeattheserverlevelcanbeestimatedbasedoneitheritsmeanvCPU

usageoritsmeanvMemoryusageoritsmeanvDiskusageoritsI/Otrafficvolume,asper[9].

>EnergyConsumptionofaVirtualized5GCor5GCNetworkSlicemaybeobtainedbysummingthe

energyconsumptionofeachnetworkfunctionortheproportionofeachnetworkfunctionthatcomprisesthenetworkslice.

>5GCEnergyEfficiency,whichissimilartothenetworksliceenergyefficiencywithoutattributionofnetworkfunctionfunctionalitytoslices.The5GCenergy

efficiencymaybeobtainedforaprivatenetwork.

Similarmetricsareexpectedtobeapplicablefor6G

networks,andmayincludevirtualizedRANcomponentswhenapplicable.

Itshouldbenoticedthatmultiplenetworkslicescanuse

thesamenetworkelement.Insuchacase,theenergy

consumptionofthenetworkelementbyaparticularnetworkslicecannotbedirectlymeasuredbutcanonlybeestimated.Therefore,energyusageandenergyefficiencymetricsofanetworkslicearedeterminedapproximately.

Ifanetworksliceprovidercannotgetafullaccessofpowerconsumptionmeasurementswithreasonableaccuracyfortheusedvirtualizedinfrastructurecomponentshostedin

apublicand/orhybridclouds,optionstoenhanceenergyefficiencyofaspecificnetworksliceareverylimited.

3.3

CurrentLimitationsandRelevancetotheDataCenterKPIs

TheKPIsdescribedinSection4.2havelimitationsthatmayatleastpartiallybeaddressedinthe6GtimeframewiththeaidofarobustsetofdatacenterKPIs.Thisincludes:

1.CurrentsustainabilityKPIsarefocusedheavilyon

energyconsumptionandenergyefficiency.Other

sustainabilitymetricssuchasdatacenterwaterusage,wastegeneration,landusage,buildingsustainability,

etc.shouldalsobeconsidered.Noteforagivendatacenter,thisincludesstaticKPIssuchaslandusageandKPIsthatmayvaryovertime,suchaswater

usage,particularlyforcooling.

2.EnergyconsumptionandefficiencyKPIsbasedon

computeresourceutilizationestimatesdonotconsider

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otherfactorssuchasdatacenterenergyconsumptionforcooling/heating.Thesemayvarybydatacenter,seasonandtimeofday(nightvsday).MorecompleteenergyconsumptionandefficiencyKPIsshould

considerallaspectsofenergyconsumption.

3.Thesourceofdatacenterenergyshouldbe

considered.Thismayincludewhethertheenergy

generationissustainable(e.g.,wind/solar/hydropowervscoal)andwhetherenergywastecanbeharvestedandreused.Thesemayvarybydatacenter,season

andtimeofday(e.g.,asthegenerationplantmixonthegridchanges).

DatacenterKPIbenchmarksconsideredinSection6providethefoundationtodetermine6GKPIsthatcanfactorintheseconsiderations.

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4ITASSETS-COMPUTE,NETWORK,STORAGE

4.1

GuidelinesforaSustainableComputeEnvironment

ToachieveNetZeroGHGemissionstargets,itisimportanttounderstandaproduct’sGHGemissionsduringtheproductionstageinadditiontotheemissionswhileinitsoperation.

Sustainabledesignofcomputingserverisanintegrated,

holisticapproachthathelpstoreduceemissionofallphasesofadatacenterlifecycle.

Whilewell-establishedprocedureandmetricsareavailabletoassessGHGemissionsfromproductsinuse,there

arechallengesincludinglackofconsistentapproachand

metricstoaccuratelyassessandcontrolofGHGemissionsreleasedduringtheproduction.Agoodpracticetodevelopasustainablecomputingserverispresentedbelow.

>MaterialSelection

?Reductionoftheembodiedcarbonstartswithmateri