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$1/WPhotovoltaicSystemsWhitePapertoExplore
AGrandChallengeforElectricityfromSolar
DISCLAIMER: Thepurpose of thispaper is tofacilitate discussion amongparticipants in the
$1/WSystems:AGrandChallengeforElectricityfromSolarWorkshop,tobeheldonAugust
1011,2010inWashington,DC. Thispaperdoesnotrepresent,reflect,orendorseanexisting,
planned, orproposedpolicy of the U.S. Government, including but not limited to the U.S.
Department of Energy. The U.S. Department of Energy does not guarantee the accuracy,
relevance,timeliness,orcompletenessofinformationherein,anddoesnotendorseanysources
usedtoobtainthisinformation. Assuch,thispaperisnotsubjecttotheInformationQualityAct
andimplementingregulationsandguidelines.
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I. IntroductionAkeyplankoftheObamaAdministrationsEnergyPolicyistoputthecountryonapathtoreduceGreen
HouseGas(GHG)Emissionsby80%by2050. Solarenergytechnologyhasthepotentialtoplayamajor
roleinachievingthisgoalbuttodatehasbeenlimitedbyhighcosts.
TheU.S.DepartmentofEnergy(DOE)estimatesthata$1/wattinstalledphotovoltaicsolarenergy
systemequivalentto56cents/kWhwouldmakesolarwithoutadditionalsubsidiescompetitivewith
thewholesalerateofelectricity,nearlyeverywhereintheUS. Asolarenergysystempricedat$1/Watt
wouldunlockthepotentialofthesuntoprovidelowcost,cleanlimitlesselectricitytotheU.S.andthe
restoftheworld,atthesamecostofcoalbasedgeneration. Atthisprice,solargeneratedelectricity
combinedwithaffordablestoragetechnologiescouldthenmeetallconventionalelectricityenergy
needs,providingsolarenergypotentially24hoursaday. Meetingthischallengewouldresultina
revolutionintheworldsgenerationanduseofenergy.
Withthecurrentrateofprogress,thecostofautilitysizedphotovoltaic(PV)systemislikelytoreach
$2.20/wattby2016,and$2.50/wattand$3.50/watt,forcommercialscaleandresidentialscalesystems
respectively. Reductionssignificantlybeyondthatinthenextfourtoeightyearsareunlikelyabsent
dramaticallynewideasandsignificantinvestment.
PreliminaryDOEanalysisonrequiredcomponentcoststoreacha$1/wattinstalledPVsystemimplies
thefollowingbreakdown: 50cents/wattforthemodule,40cents/wattforthebalanceofsystemand
installation,and10cents/wattforthepowerelectronics. Privateinvestmentisunlikelytobringabout
thetypesofambitiousadvancesrequiredtomeetthesegoalsasthecapitalmarkethasfocusedfunding
onshortertermcommercializationgoalsandinternationalmarketswithattractivegovernmentsupport
andhighelectricityrates.
ThiswhitepaperwasdevelopedbyDOEstafftostimulateadialogueabouttechnologypathwaysto
achieve$1/watt.Thepapercontainsinitialideasonhowtoachievesignificantreductioninthecostof
modules,powerelectronicsandbalanceofsystem/installation. Forexample,analysissuggeststhat
moduleswith25%efficiency,powerelectronicswithdoubletheratedlifetime,andsimplerandquicker
PVinstallationmethodsareallrequired.
II. TheTechnicalChallengeInstalledPVarraypricesforutilityscalesystemswere$8/wattin2004andbidsbelow$3.50/wattare
expectedbytheendof2010ifnotsooner. Residentialandcommercialpricesareover$6/wattsince
theyaremuchsmallerinscaleandincurmuchlargerinstallationpricesandretailmarkups. With
currentmarkettrendsandcostreductionopportunities,utilityscalesystemcostsareexpectedtoreach
$2.20/wattby2016ifnonewprogramislaunched. The$1/wattgoalwillrequireamajorchangeinthe
rateofinnovation. (SeeTable1.)
Reachingthegoalwillrequiredramaticimprovementsinatleastthreeareas(eachisdiscussedin
greaterdetailinAppendicesEandF):
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InstalledSystemPrice($/W)
2010 2016 $1/Watt
Module 1.70$ 1.05$ 0.50$
BOS/Installation 1.48$ 0.97$ 0.40$
PowerElectronics 0.22$ 0.18$ 0.10$
3.40$ 2.20$ 1.00$
CostofEnergy($/kwh)
2010 2016 $1/Watt
Module 0.063$ 0.037$ 0.018$
BOS/Installation 0.055$ 0.034$ 0.014$
PowerElectronics 0.008$ 0.006$ 0.004$
O&M 0.013$ 0.009$ 0.003$
0.139$ 0.086$ 0.038$
Table1:Potentialutilityscalesystemcostbreakdowntoreach$1/watt
(notecapacityfactorsassumedare26%in2010and28%in2016)
Arrays: Higharrayefficiencyisessentialbothforreducingarraycostsandcuttingthearea(andthuscost)ofinstalledarrays. Fortunately,therearetechnologypathwaysthatmightachieve
thisgoal. Itisexpected,however,thatthemostpromisingislikelytobeonethatdoesnot
requireglassandcanbedepositedinexpensivelyonathinmetalorpolymersubstrate.
Reachingthegoalwillrequirefindingwaysto(a)designmanufacturablecellscapableof
achievingefficiencies
demonstratedinlaboratories
and(b)makinguseofthekinds
ofrolltorollproduction
devicesorotherapproaches
thatgreatlysimplify
manufacturingprocesses.
PowerElectronics:ConvertingtheDCoutputof
arraysintohighqualityACat
usefulvoltagesrequires
equipmentthataddsbothto
initialinstalledcostandto
maintenancecostssince
currentdesignsoftenfailafter
10years. Buildingonongoing
powerelectronicsworkatDOE,
atleasttwopromising
approachescouldbepursued:
(a)radicalredesignofcurrentlargeinverterunitsanduseofinnovativecomponents,and(b)
designingmodularinvertersthatcouldbecheaplymassproducedandattachedtoeachmodule.
Installation:Thecostofmountingandwiringarraysandtheassociatedequipmentisabouthalfthecostoftodayssystems. Twoapproacheswillbepursuedtoachievethedramaticcost
reductionsrequired:(a)installingarraysinfieldsonlightweightframeswithequipmentthathas
thesophisticationofagriculturalcombinescapableofcoveringhundredsofacresaday,and(b)
findingwaysofbuildingPVarraysintobuildingcomponentssuchasroofingsothatthe
incrementalinstallationcostcouldbeverylow. Arraysthatfollowthesunaresomewhatmore
expensivethaninstallationsthatdontmovebutcanproducemoreelectricityperyearperwatt
ofinstalledPVandcanproducemoreenergylateinthedaywhenmanyutilitiesneedmost
power. Trackingisusuallyalsoneededforunitsthatconcentratesunlightonhighefficiency
cells. Concentratingsystemsaddtocostsbutcanreducetheareaandcostofthephotovoltaic
devices.
Whileeachoftheseareascouldbepursuedasaseparatetask,thesuccessoftheprojectdependson
ensuringthateachoftheprogramsunderstandsthechallengesfacedbyotherareas. Arraysshould,for
example,bemassproducedforeasyinstallation.
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III. OtherRequirementsAnumberofotherobjectiveswillneedtobemetinordertomakea$1/wattsystemcommercially
viableandscalabletomeetlongtermenergyneeds. Inordertorepresentasignificantadvancement
fromexistingindustrytrendsandmakeasignificantimpactonAdministrationGreenhouseemission
goals,the$1/wattgoalshouldbedemonstratedby2017. Thetargetcouldbedemonstratedbyfull
systemsorincrementaltoexistingsystemcosts,suchasforPVsystemsintegratedwithinnewroofing
systems. Toensurelargevolumescalability,the$1/wattsystemshouldbebasedonearthabundant
materialsandcapableoffullrecycling. Finally,the$1/wattsystemshouldmeetallapplicablesafetyand
environmentalstandards.
$1/wattinstalledby2017:DefiningtheObjective
By2017: Demonstrationofallkeycomponentsandinstallationmethodsinsystemsatleast5MWinsizeandinitialproductionordersforequipmentcapableofdelivering$1/watt
installedsystemsin2017
Includesallcomponents,equipmentandinstallationprocessestoproducegridcompatibleelectricity
Targetcouldbemetwithsystemsinstalledonthegroundoronbuildings Earthabundantmaterials Recyclablecomponents Meetsallapplicablesafetyandenvironmentalstandards
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Appendices
AppendixA: PotentialImpactsof$1/watttoU.S.ElectricitySystem
AppendixB: BusinessasusualandthechallengeoftheUSelectricitymarket
AppendixC: CostGoalsoftheCurrentDOEprogramand$1/WGoalforutilityscalesystems
AppendixD: ManagementAlternatives
AppendixE: PotentialPathwaystoCostReduction
AppendixF: ChallengesforCostReductioninArrayProduction
AppendixG: PreliminaryanalysisofEfficiency,Cost,andReliabilityBarriers
AppendixH: TheneedforGovernmentfunding
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AppendixA:PotentialImpactsof$1/watttoU.S.ElectricitySystem
PreliminaryNRELanalysisconductedwithReEDS1andSolarDS2suggeststhatifthe$1/wattgoalis
reachedby20203,morethan100GWofPVcouldbeinstalledcumulatively,representingabout5%of
thenationselectricgenerationcapacity.4 By2030,installedcapacitycouldgrowto389GW
representing14%ofU.S. generationcapacity.
Ifthesecapacityadditionsarerealized,utilitysystemswillneedtoadjusttheirgenerationmix
andoperationstoadapttolargeramountsofsolarenergygeneration. Theanalysisindicates
thatif14%ofautilitysenergycomesfromsolar,theseadjustmentscouldberelativelysmall,
onlyminimalamountsofnewtransmissionandstoragewouldberequired. Thetotalamount
ofnaturalgaspoweredintermittentandpeakingcapacitywouldfall,butahigherfractionof
thisequipmentwouldneedtobemaintainedas"spinningreserve. Inexpensivestoragewould
cutoverallcosts.AttheselevelsofPVadoption,consumerpricesofelectricitycouldbe2%lowerin2030ifthe
$1/wattgoalismet. Further,by2030CO2emissionsfromthepowersectorcouldbereduced
by
approximately
213
MMT
CO2
annually
and
the
growth
of
CO2
emissions
from
the
sector
couldbecutinhalfby2030.
1NRELsRenewableEnergyDeploymentSystem(ReEDS)isalinearcapacityexpansionmodelthatoptimizestheregional
expansionofelectricgenerationandtransmissioncapacitywithin356regionsofrenewableresourcedatawhilespecifically
addressingthevariablenatureofsomerenewableresources.http://www.nrel.gov/analysis/reeds/2NRELsSolarDeploymentSystem(SolarDS)isamarketpenetrationmodelforcommercialandresidentialrooftopPV,which
takesasinputregionalelectricityprices,financialincentives,regionalsolarresourcequality,androoftopavailability. Denholm,
P.,Drury,E.,andMargolis,R.,2009, TheSolarDeploymentSystem(SolarDS)Model:DocumentationandSampleResults,
NREL/TP61245832.3TheReferenceCaseusespreliminarytechnologycostandperformanceassumptionsbeingdevelopedforanother EEREstudy
andassumesa30%ITCforsolarthrough2016duetoARRAandthentheITCexpiresafter2016thathasnotyetbeenpeer
reviewed. The$1/Watt2020CaseusesthesametechnologyandpolicyassumptionsastheReferenceCase,butthecostofPV
rampsdownto$1/Wattby2020forutilityscaleandcommercialapplications.Forresidentialapplications,PVisavailablein
2020at$1/Wattfornewconstructionwithroofresurfacingmodeledbya5%houserebuildrateandretrofitsata40%cost
penalty(or$1.40/Watt).Forbothcases,ReEDSandSolarDSwereruntogetherinaniterativefashion. Thefossilandnuclear
numbersreflectpreliminaryestimatesbyanengineeringconsultingfirmandhavenotbeenreviewedbyDOE. Theyarebeing
usedhereasplaceholdersonly,toallowtheexplorationofthepotentialimpactof$1/WinstalledPVscenariosforthisstudy.4Theseresultsarepreliminary,notpeerreviewedorvettedforcitationorquotation.Properstudyofthisissuewouldrequire
additionalReEDS/SolarDSanalysistoprovideamorerobustunderstandingofthepotentialimpactofreachingthiscostgoalon
theU.S.electricitysystem.
2030Results ReferenceCase $1/WattnoITCpost2016
%GenerationofPV 1% 14%
CumulativeInstalled
Capacity(GW)
40GW 389GW,
232GWUtilityscale,157GWDistributed
NationalAverage
ElectricityPrice
10.45cents/kWh 10.23cents/kWh
AnnualCO2emissions
fromthePowerSector
2,408MMTCO2 2,194MMTCO2
Table2:Potentialim actontheU.S.electricit s stemin2030fromthede lo mentofa 1 WPVs stemb 2020
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Figure1:GeographicDiversityofPVDeployment
Figure1showsthatwiththe$1/Wattsystemssolarelectricitycouldbecostcompetitivewithother
formsofgenerationinalmosteverystateinthecountryby2030.
SummaryResultsfromReEDSandSolarDSCasesInstalled
Capacity
2010 2030 2050
(GW) Reference $1/WCase Reference $1/WCase Reference $1/WCase
SolarPV .3 .3 40 389 83 592
Wind 35 35 49 38 118 70
Storage 21 21 23 24 24 30
NG 389 389 516 412 635 567
Coal 308 308 302 303 355 301
Nuclear 100 100 96 96 57 57Table3:InstalledCapacityinReferenceand$1/WattCases
TheresultsfromtheReferencecaseandthe$1/WattcasearepresentedinTables3and4andarenot
anofficialDOEperspectiveonthefuture,butpossibleoutcomesbasedononesetoftechnologycost
andperformanceprojectionsandotheraspectsoftheReEDSandSolarDSmodels,withparametersas
suppliedbyanexternalengineeringconsultingfirm,whichhavenotbeenpeerreviewednorreviewed
byDOE. Thesevaluesfornuclear,fossil,andrenewabletechnologiesarebeingusedhereas
placeholdersonly,toallowtheexplorationofthepotentialimpactof$1/WinstalledPVscenariosfor
thisstudy.Marketpenetrationlevelsofdifferenttechnologiescanbeattributedtoanumberoffactors
includingprojectionsoncostandperformance.
Generation 2010 2030 2050
(TWh) Reference $1/WCase Reference $1/WCase Reference $1/WCaseSolarPV 0.4 0.4 60.5 654 128 986
Wind 115 115 170 129 427 250
NG 767 767 1025 675 1313 1188
Coal 1886 1886 2235 2138 2629 2129
Nuclear 790 790 757 757 448 448Table4:ElectricityGenerationinReferenceand$1/WattCases
>30
20 30
10 20
5 101 5
0.1 1
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AppendixB: BusinessasusualandthechallengeoftheUSelectricitymarket
Figure2belowhighlightsthecurrentstateoftheartforthetwoleadingphotovoltaictechnologies,
waferbasedsiliconandthinfilmCdTe. ThecostsarebasedonsystemsinstalledinPhoenix,AZanddoes
notincludefederal,state,orutilityincentives.
Figure2:ComparisonofcurrentandprojectedSolarPVcosts(Phoenix,AZ)toUSwholesaleelectricityrates(wholesalerates
ofleadingsolarenergyadoptedcountriesincludedforreferencetoUSratesonly)
TheUSandothercountriesnationalaveragewholesaleelectricityratesarerepresentedbybandson
Figure2(Source:EIA). Theindustryiscurrentlyfocusedonthosemarketswithhighelectricitypricesand
highsubsidies. SincePVisalreadyattractiveinthoseregions,manufacturersarefocusedonservicing
thoseopportunitiesthroughincrementalimprovementsthatincreasetheirprofitabilityandmarket
share. Reaching$1/WisachallenginggoalthatismoreimportantfortheUSthansomeofthoseother
countries. Projectionsforcostreductionsfortheleadingsiliconandcadmiumtelluridetechnologies
suggeststhatutilityscalesystems,whilealreadyattractiveinotherregionsoftheworld,willnotbe
broadlycompetitivewiththeUSaveragewholesalerateofelectricitywithoutsubsidiesby2016.6,7,8,9
Thecostreductionsneededareunlikelytobeachievedwithtechnologiesnowinwidespread
production. AnalysisshowningreaterdetailinAppendixFsuggeststhatcurrentcrystallinesiliconand
cadmiumtelluridetechnologiesarereachingthelimitsofwhatcanbeachievedthroughincremental
improvementofcurrentproductionmethods. Dramaticallynewideasarerequired.
6AppendixC
7AppendixE
8AppendixF
9FirstSolarAnalystInvestorMeeting,LasVegas,June24,2009
0.0
5.0
10.0
15.0
20.0
25.0
30.0
$0.25 $0.75 $1.25 $1.75 $2.25 $2.75
LCOE(centsperkWh)
NonModuleCosts($perWp)
UnsubsidizedUtility
Scale
Solar
PV
Energy
CostsMinimumSustainableModulePrice,MedianTechnologyEfficiency
Phoeniz,AZ;FixedPower(20MW)GroundMount
CdTeToday(2010),
$0.98/Wp,10.8%
CdTeProjected(2014),
$0.68/Wp,14.4%
cSiToday(2010),
$1.70/Wp,
14.4%
cSiProjected(2016),
$1.05/Wp,17.4%
2015ProjectedUSUtility WholesaleElectricityPrice
Ja an Wholesale Electrict Price
GermanWholesaleElectricityPrice
ItalyWholesaleElectricityPrice
DollarperWattGoal
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AppendixC: CostGoalsoftheCurrentDOEprogramand$1/WGoalforutilityscalesystems(Figure3
&5)
Figure3:CostGoalsoftheCurrentDOEProgram(2016)vs.$1/WGoal(2017)forcSiutilityscalesystems
$8
$1.70
$1.05$0.50
$0.22
$0.18
$0.10
$1.48
$0.97
$0.40
$
$1
$2
$3
$4
$5
$6
$7
$8
$9
2004 2010(Est.) 2016(CurrentGoal) 2017($1/WGoal)
InstalledSystem
Cost($/W)
BOS/Installation
Inverter
PVModule
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Table5:$1/WGoalofUtilityScaleSystemsbasedoncSi
ComponentCost($/W)
2010
(Est.)
2016
(Current
Goal)
2017
($1/W
Goal)
PVModule 1.70$ 1.05$ 0.50$Semiconductor 0.54$
RawMaterials(Sifeedstock,sawslurry,sawwire) 0.36$
Utilities,Maintainence,Labor 0.04$
Equipment,Tooling,Building,CostofCapital 0.06$
Manufacturer'sMargin 0.08$
Cell 0.45$
RawMaterials(eg.metallization, SiNx,dopants,chemicals) 0.18$
Utilities,Maintainence,Labor 0.04$
Equipment,Tooling,Building,CostofCapital 0.04$
Manufacturer'sMargin 0.20$
Module 0.70$
RawMaterials(eg.Glass,EVA,metalframe,jbox) 0.26$
Utilities,Maintainence,Labor 0.01$
Equipment,Tooling,Building,CostofCapital 0.01$
Shipping 0.08$
Manufacturer'sMargin 0.34$
RetailMargin $
Inverter 0.22$ 0.18$ 0.10$
Magnetics 0.03$
Manufacture 0.05$
BoardandElectronics(Capacitors) 0.07$
Enclosure 0.04$
Power
Electronics 0.03$
BOS/Installation 1.48$ 0.97$ 0.40$
MountingandRackingHardware 0.25$
Wiring 0.14$
Other 0.17$
Permits 0.01$
SystemDesign,Management,Marketing 0.15$
InstallerOverheadandOther 0.19$
InstallationLabor 0.38$
Total 3.40$ 2.20$ 1.00$
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AppendixD: ManagementAlternatives
Severaldifferentresearchmodelsshouldbeconsidered. Theseinclude:
1. SEMATECH: TheSEMATECHresearchconsortiumwasconceivedin1986outofaconcernthattheUnitedStateswasabouttolosetheentiresemiconductormanufacturingindustry
totheJapanese. JointlyfundedbytheDefenseAdvancedResearchProjectsAgency
(DARPA)andindustry,itreportedtoaboardwithonegovernmentmember. The
consortiumwonacompetitivesolicitation. IthadaClass1cleanroomoperatingin32
weeksandattractedthebestpeopleintheindustry. Itdevelopeddetailedroadmaps
showingwhatneededtobedonetoproducenextgenerationCMOSsemiconductorsand
focusedresearchonchallengesthecorporatemembersshared. Governmentfunding,and
governmentboardmembership,endedin1995,andtheorganizationcontinuesasan
independentorganization.
a. Advantages: Theorganizationensuresthatthetopicschosenarecloselyalignedtotherealneedsofindustry. Itcouldoperateflexiblyandquicklywithoutfederalred
tape.
b. Disadvantages: Theorganizationwasabletoidentifyanumberofcriticalareas(suchasmanufacturingequipment)whichwereneededbyallmembersbutwere
notpartofthebusinesseslinesofthememberswhichrevolvedaroundthedetails
ofchipdesignnotmaterialsormanufacturingtechnology. Thismeantthatthey
couldsharetheintellectualproperty. ConversationswithPV manufacturershave
raisedconcernsthatthismodelmaybedifficulttoapplytothearrayindustrysince
materialsandmanufacturingdetailsareatthecoreoftheirintellectualproperty.
2. SkunkWorks: TheLockheedAdvancedDevelopmentProjects(akaSkunkWorks)puttogether
a
team
that
crafted
some
of
the
most
amazing
aircraft
ever
built
including
the
U
2andtheSR71anddiditinrecordtime. TheSkunkWorksteamdesignedandbuilta
prototypeoftheXP80,oneofthefirstturbojets,inonly143daysandplayedamajorrolein
theKoreanWar.
a. Advantages: Allowsahighlycreativeteamtoaddresscomplexapplieddesignandfabricationproblemswithfewconstraints.
b. Disadvantages: Thismodelmaynotworkwithoutanexclusiverelationshipwithanindividualcorporation. Italsoreliesonextraordinaryleadership. Thecreativityfor
whichtheorganizationwasfamousbegantodissipatewhenleadershipchanged.
TheinfamousF22aircraftwasdevelopedbythesameorganization.
3. HUBs: HUBshavetheabilitytopulltogetheradiverseresearchteamandformtightallianceswithindustrypartnersensuringactivemovementofideasoutandproblemsin.
a. Advantages: Modeliswellestablishedandcouldbesetupquicklyb. Disadvantages: TheHUBsarewelldesignedtoaddressarangeofindividual
researchproblemsbutarenotmanagedaroundtightroadmapsaimedatmeeting
hardprice/performancetargetsbyadatecertain. Itmightbepossibletochange
this.
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4. GeneralGroves: TheManhattanprojectsucceededbecauseofcreative,butveryhierarchical,management,ledbyLt.Gen.LeslieGroves. Someofthenationsmostcreative
scientistswereallowedroomforcreativity,buttightlyfocusedonthepracticalproblemsat
hand.
a. Advantages: Withtherightmanagementitcanbuildcreativealliancesbetweenscientificresearchandthedesignofpracticaldevices.
b. Disadvantages: Theprojectdidnotneedtodevelopcommercialproductsorconcernitselfwithintellectualpropertyorsimilarissues. Itwasabletoavoidmost
ofthelimitationsthatcreatedelaysinfederalprocurementandhiring. Anditwas
extraordinarilyexpensivesincethefederalgovernmentpickeduptheentirebill.
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AppendixE: PotentialPathwaystoCostReduction
Atoplevelanalysisoffirstestimatepotentialsystemandcomponentperformancerequirementsand
characteristicsofa$1/WsystemissummarizedinTable6. Oneofthegreatestopportunitiesforcost
reductionliesinmoduleandsystemefficiencyenhancements. Efficiencyadvancesreducenotonlythe
PVmodulecostbutalsomuchoftheBalanceofSystems(BOS)andfixedsystemcosts. Forexample,if
modulesweretwiceasefficient,withthesamelaborandmountinghardware,twicethepowercanbe
obtained,
thereby
reducing
the
BOS
cost.
AnalysisofthemanufacturingandinstallationcostsofPVsystemsrevealsseveralpathwaystoachieve
the50cents/wattmodulecosttargetthatisconsistentwitha$1/watttotalinstalledsystemcost. The
primaryrequirementsarethatmoduleefficiencyneedstobe25%orgreaterandproductlifetimeneeds
toexceed30years.10 MeaningfulBOScostreductionisnotpossiblewithoutraisingmoduleefficiency.
Productlifetimeneedstobelongenoughtoamortizetheinstallationanddisposalcosts.11
A. LowCostArraysThegoalistobuildanarrayatacostwhichmakesapriceof50centsperwattfeasible,whileachieving
efficiency
greater
than
25%
and
a
lifetime
of
at
least
30
years
with
minimal
maintenance.
The
modules
mustbebuiltattremendousvolumewhichrequiresthattheybebasedonearthabundantmaterial.
Andtheymustberecyclable. Thelowcostsuggeststhattheyalmostcertainlywillnotusetraditional
thickglassorsignificantamountsofpurifiedsiliconthatcontributesignificantlytotodaysarraycosts.
10AppendixF
11NonModuleCostSensitivitytoEfficiency,DOE$1/WWorkshopPhotovoltaic(PV)IndustryPrimer,July2010.
Characteristic ValueorQualifier
Module
Efficiency >25%
Substrate Lowercostandweightthanglass
Reliability 30yearsorcanbereplacedwithminimumlabor
Materials Earthabundant, nontoxicorestablished
recyclingplan.
BOS/Installation
Labor Canbedonewithnonspecializedlabor
Process Lightweight(easeofhandling,nospecial
equipment)
Assembly Snaptogethermechanicalandelectrical
PowerElectronics
Efficiency >95%,improvedmodulepeak
powermanagement
Reliability 30years
Assembly Integrationofwiring,componentstominimize
electricalconnectionsTable6:SuccessCharacteristics
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Devicescapableofmeetingthegoal:
AsshowninFigure4,commercialcellsoperatefarbelowtheoreticalpotentialefficienciesandwell
belowefficienciesdemonstratedinthelaboratory.12,13 Duetothecompoundedsystemcostbenefits
associatedwithefficiencygains,closingthesegapsiscritical.
Wafersiliconisamaturetechnologyandefficienciesofcommercialcellsareapproachingtheoretical
limits. Thinfilmapproachescanreach25%orhighermoduleefficiencyoninexpensivesubstrateswith
potentiallyscalableandcosteffectivedepositionmethodologies,butsincetheyarecomparativelynew,
thegapseparatingtheoreticalfromproductionarraysisquitelarge. Cadmiumtelluridearraysarein
largescaleproductionbuthaveonlyachieved11%moduleefficienciesinproduction;and17%in
laboratorydevices. Thereisalsoconcernthatthecostofreclaiming,andrecyclingcadmiumcontaining
PVmoduleswillescalateinthefuture.14 ThinfilmCIGS,whichalsocurrentlycontainsverysmall
12http://www.tfp.ethz.ch/Lectures/pv/thinfilm.pdf
13http://scitation.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=APPLAB00009500001616330
2000001&idtype=cvips&prog=normal&doi=10.1063/1.3243986&bypassSSO=1 14
http://seekingalpha.com/tag/transcripts?source=headtabs
Figure4:Gapsinefficiencybetweenbestlaboratoryresultsandtheoreticallimitsandbetweenproductionandbest
laboratoryresultsprovideopportunitiesforimprovement. (TheoreticalbasedonShockleyQueisserlimitandbandgapof
semiconductor. NRELverifiedbestcellefficiency)
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amountsofcadmiumsulfide,hasevengreateropportunityforefficiencyimprovementwith10%to11%
inproductionandmorethan20%inthelab. ThefuturecostofCIGSmodulesandthistechnologys
abilitytocontributetoverylargescalePVpowermarketsdependsupontheavailabilityofindiumand
gallium. CZTS,amaterialsystemverysimilartothinfilmCIGSbutwithindiumandgalliumreplacedby
moreearthabundantzincandtin,providesarelativelynewopportunityforatransformationalchange
ofthePVmarketinsupportofreaching50cents/wattmodulecosts.
Organicphotovoltaic(OPV)anddyesensitizedcell(DSC)deviceshavereceivedsignificantinterestas
promisingpathstoveryinexpensivesolarmodules. Tobecommerciallyviable,thesetechnologiesmust
solvesignificantissueswithefficiencyaswellaslifetime. Significantbreakthroughsintheseareasare
stillneeded.
ConcentratedPV(CPV)takesadifferentapproachtoconventionalflatmodulesbyleveragingadvanced
opticalsystemstoshiftthecostbalanceofcellmanufacturingtomodulemanufacturing. Higher
efficiencyCPVdevicesaswellasinnovativesystemsapproachestoCPVmoduleassemblycouldincrease
thetypical25%orlowerefficientmodulescurrentlyproducedtogreaterthan35%moduleefficiencyif
thesemiconductordevicecanexceed50%efficiency. Advancesinopticaldesign,manufacturingand
assemblywouldalsoberequired. Analternativeapproachistoapplyliftoffprocesstothehigh
efficiencyIII/VcellsusedinCPVmodules. Theseprocesseshavethepotentialtosignificantlyreducethe
costsofIII/Vcellsandmakethemavailableforunconcentratedflatplateorflexiblemodules.
Whiletheuncertaintiesaremuchhigher,itispossiblethatinexpensivearrayswithefficienciesmuch
higherthanthoseshowninFigure4canbebuiltusingadvancedmultijunctionthinfilmsformanyIII/V
andII/VIsystemsthroughbandgapengineeringsuchastandemjunctionstructuresonthinfilm
materials(Ex:InSbonthinfilmCdTe,orGaPonthinfilmSi). Suchinnovationswouldrequire
breakthroughsintunneljunctionformationoverlargeareasacrosspotentiallyhighlylatticemismatched
polycrystallineinterfaces.Perhapsrecentadvancesinthermoelectricdevicescouldmakeitviablefor
photovoltaicdevicesinaconcentratingsystem.
ModuleProduction
Technology:
Lowproductioncostsare
clearlyessentialtomeetthe
pricegoals. Thiswill
requiredramatic
innovationsthatcancut
bothcapitalandlaborcosts
inarraymanufacture.
BasedonDOEanalysis,cellsproducedbelow50centsperwattwouldlikelymean10centsperwattfor
capitaldepreciation,23centsperwattformaterials,and6centsperwattforlabor.
2010 2016Proj
Cost Cost Cost($ /W) Cost($/m2)
Capital $0.24 $0.20 $0.10 $28
Materials $1.11 $0.49 $0.23 $68
Labor $0.27 $0.12 $0.06 $17
Margin $0.79 $0.24 $0.11
TotalModule $1.70 $1.05 $0.50
$1/WTarget
Table7:DetailedcostbreakdownforcSiPVmodule($/m2valuesassume29%
efficiency
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Capitalcosts:Assumingasevenyeardepreciationperiod,initialcapitalcostswillneedtobeonthe
orderof70cents/watt. Thisisapproximately50%lowerthanthecostsoftodaysstateoftheartthin
filmPVfacilities.
Materialcosts: ifweassumeanextremelyambitiousmoduleefficiencyof29% thelimitofwafered
siliconreachingamaterialscostof23cents/wattwouldbeequivalenttoanareacostof$68/m2
. Even
atthishighefficiency,currentcommoditymaterialssuchcoverglass,substratesandbacksheets,silicon,
silver,aluminumframingcouldconsumetheentirebudgetwithlittlecurrentpotentialforcost
reduction(Figure6showsagraphicaldepictionoftheseandothermaterials). Atcurrentcosts,glass
withTransparentConductingOxides(TCO)andantireflectioncoatingmighttakeupasmuchas16%
to25%ofthistotal,indicatingtheneedforcheapersubstratesandbettercoatingtechnology. Frames
andotherstructuralpartsmighttake
upasmuchas25%ofthetotal
indicatingtheneedforframeless,
possiblyflexiblemoduletechnology.15
Productioncostscanbereduced
sharplywithprocessinnovations
includinglowcosthighlyscalable
approachessuchasdepositiononlow
costnonwoventextilesorrolltoroll
filmprocessing(Figure6).
Innovationsinanumberofareas
couldsharplycutproductioncostsfor
advancedmoduledesignsincluding:
Lowcostorvirtualsinglecrystalenablingsubstratesreducingwasteassociatedwithsawingwafers,therebyreducingmaterialsusage(gramsperwatt)byafactorof2ormore
Ultrathinwafersthatnotonlyenablegreatermaterialutilization,butalsoinherentlyimprovecertainlossmechanisms(ie.bulkrecombinationlosses);optimizewaferthickness
Lowstresstabbingtechniques,suchasprepatternedbacksheetsthatnotonlyenablethestringingofultrathincellsintomodulesbutmayalsoenablesemiflexibleroofinglaminates,
greatlyreducingdeploymentcosts.
Defectengineeringandadeeperscientificunderstandingoftheroleofimpuritiesandstructuraldefectsaswellaswaystomakethemelectricallyinactivecanimprovetheefficiencyofsolar
cells
FlexiblePVsolutionsthatenableinnovativeBIPVandfielddeploymentapproachesthatcouldsignificantlyreduceBOScosts.PVmodulesthatserveadualpurposeasabuildingfacade,or
roofingmembranefurtherreduceinstallationcosts.
15NRELAnalysismemo,SolarManufacturingCostModels,AlanGoodrich,April29,2010.
Figure5:SiliconPVmodulecontainsmanycommoditizedraw
materialsincludingsilicon,glass,andaluminum. Thechallengewill
betoreducethecostsorutilizationofthesematerialswhile
improvingmoduleefficiency.(Graphicsource:Hisco)
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Inexpensiveandhighperformance(conductivity,transmissivity;absorption)TCOsordesignsthateliminatetheneedforvacuumprocessingofTCOsentirelyreducestheseriesresistanceof
PVmodules.
AtomicbarriersthatcanprovidebettermoistureimpermeabilitytothePVdevicethanglass,therebyincreasingreliabilityandfunctionalmodulelifetime.
HighgrowthrateepitaxyofGroupIV,III/V,andII/VIsemiconductorsonlowcostsubstrates.VeryhighfrequencyplasmadepositionorotherprocesseshasthepotentialtoincreasePV
depositionrateandreduceequipmentcostby10Xwhilemaintaininglargeareauniformityand
materialqualitythroughnew approachestosourceandprocessdesign.
Breakthroughapproachestodepositionfromatmosphericpressureliquidprocessingcouldsignificantlyincreasethroughputandlowerdepositioncosts
Plasmonicsandnanowirethinfilmscanenhancelighttrapping
Combinatorialapproachestomaterialsdiscoveryandcharacterizationaswellas
deviceoptimizationcangreatlyspeed
upthedevelopmentofnew
technologiesandallowefficiencyto
approachtheoreticallimits. APV
MaterialsGenomeProjectcouldenable
researcherstorapidlyscreencandidate
PVabsorbersystemsandlinktheoretical
understandingPVmaterialswith
experimentalconfirmationofmaterialproperties.
Figure6:RolltoRollcontinuousprocessingcansignificantlyreducemanufacturingcostshasithasdoneinanumberof
otherindustries
Figure7:Highlyautomatedagricultureequipment
revolutionizedharvestingofcrops.http://www.businessweek.com/magazine/content/08_22/b4086
072681496.htm?chan=search
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B. BalanceofSystemandSystemInstallationTheBOSandinstallationcostsincludeforexample:mountingandrackinghardware,installeroverhead,
permitsfees,landpreparation,andinstallationlabor. This
currentlyaddsabout$1.48/watttothecostofaninstalled
system. The$1/wattgoalrequiresareductiontoabout
$0.44/watt(Table1). Itwillprobablybenecessarytocut
installationlaborcoststoapproximately5cents/wattand
mountingandrackinghardwaremustreducetoabout20
cents/watt. Thiswillrequirefundamentallynew
approaches.
Asabenchmark,amodern20MWutilitysolarplantcovers
approximately150acres. Theinstallationtakesacrewof
100peoplesixmonthstoinstallcompletely.16 Laboralone
adds10centsto15cents/watt. Twoprincipalstrategiesfor
reducinginstallationcostswillbein
competition: (1)reducingthecostofinstalling
hugearraysinopenfields,and(2)
incorporatingthearraysintobuilding
componentsthatcouldsubstituteforstandard
roofingmaterials.
FieldInstallations:
Modernagricultureuseshighlyproductive
machinescalledcombinesthatcanprocess
(reaping,binding,andthreshing)200acresaday,as
showninFigure7. Thesemachinesofferamodelof
whatcouldbepossibleemployinginnovative
roboticapproachestoPVfieldinstallation.
LimitedautomationforPVinstallationisalreadyin
existencewherecurrentlysomePVinstallations
machinesdrivepostsintotheground,asshownin
Figure8,butthisdeviceisdesignedonlytoputtens
ofthousandsofpostsintheground. Muchgreater
16Quote:DataprovidedbyaninstallerforcSiarraydeployedwith1axistracking.
Figure8:Lowlevelsofautomationforsolar
fieldinstallationsarejustbeginningtobe
developed. http://www.philadelphiasolar.eu/philadelphia_solar_gallery.html
Figure9:PlasticcoveringastrawberryfielddemonstratingthepotentialofrollingoutPV.
http://photosbygarth.com/sampleslg/050115_202p_9584lg.jpg
Figure10:Solarrooftilesdemonstratingthepotential
forlargeautomatedsnaptogetherPV.
http://www.reuk.co.uk/OtherImages/solartiles.jpg
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costreductionscouldbeachievedusingadevicethatcombined1)postdigging;2)rackhardware
installation;3)modulemountingand4)electricalconnection.
Inadditiontoautomatedinstallation,innovativearraydesignscanleadtomajorcostreductions. These
include:
RollingOutPV(i.e.,PVonaflexiblesubstrate,similartohowplasticisrolledacrossfarmfieldsforfumigation,Figure9).
ContinuousPV(i.e.,modulesthatcannearlycontinuouslybedeployedanalogoustopavingcrewsthatdrivedowntheroadremovingpavementandinstallingfreshpavementinacontinual
process)
BuildingInstallations:
Installationcostscanalsobecutsharplyifthephotovoltaicarrayscanbeinstalledasabuildingmaterial.
Arraysintegratedintoroofingmaterialscouldcombineweatherproofingwithelectricgeneration. The
incrementalcostofinstallingthearrayscouldbequitesmallandlittleornoadditionalstructuralsupport
wouldberequired. Thesystemswouldbeeasiesttodesignfornewconstruction,butitispossiblethat
thedevicescouldbeintegratedinmembranesorotherequipmentusedtoreplaceworncommercial
roofing. OnesuchconceptisshowninFigure10usingmodulesthatrapidlyinterconnectanddisplace
thecostsofcurrentroofingmaterialsandlabor.
Centraltoeachoftheseproposedinstallationcostreductionstrategiesistheneedtoreducethe
amountofspecializedlaborthatisrequired. Thefollowingsectionsproposemethodsforintegrating
intothemodulethepowerelectronicsandothersystemcomponents,therebysignificantlydecreasing
PVinstallationlabor.17
C.
Power
electronics
Thepowerelectronicsspecificallytheinverteristheinterface
betweenthemoduleandthegridconvertingthedirectcurrent
outputofthearraysintothehighvoltagealternatingcurrent
neededformostpowerapplications. Itcurrentlyaddsabout22
cents/watttosolarinstallationsandthismustbecuttoabout8
cents/watttomeetthegoal.18 Thecostandperformanceofthe
invertermaynotbeadominantportionofthetotalinstalled
systemscostbutitisasignificantportionandneedstobe
addressedinordertoachieve$1/watt. Today,thepower
electronics(1)arethedominantpointoffailurefortheinstalled
systemandareamajorcomponentofmaintenance,(2)are
17Electricalcomponentinstallationlaborcanaccountforasmuch78%ofthemanhoursrequiredforautilityscale
system. Thenationalaverage(source:RSMeans,2010)burdenedelectricianrateis$72.85/hour. PVhardware
installedbygeneralorroofingcontractorswouldprovideasavingsofupto19%.18
Dataprovidedbyananonymoussystemsinstaller.
Capacitor
Type
FailureRate
(%/1000h)
Electrolytic 0.2
Tantalum 0.1
Paper 0.05
Ceramic 0.025
Table8:ApproximateReliabilityof
capacitortypes
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responsibleforalossofapproximately4%ofalloftheelectricitygenerated,and(3)addcomplexityand
costtowiringandinstallation. Megawattscaleinvertersweighinexcessof10,000pounds,andoccupy
morethan500cubicfeetofspace.
Currentgenerationinvertersareonlyexpectedtolastabout10to15years,
requiringatleastonereplacementduringananticipatedlifetimeof30years
orlongerforaPVarray. Thislimitedlifemeansthattheinverters
contributiontoalevelizedcostofelectricityishigherthantheoriginal
installedcost. Onereasonforlimitedlifetimeistheuseofelectrolytic
capacitorswhichhavefailureratesthatare10timesgreaterthanthatof
lowerenergydensitythinfilmcapacitors(seeTable8,Figure11). Itis
projectedthatcurrentcostreductionsintheinverterwillbeachieved
throughadvancedcircuitarchitecturethatavoidstheneedforelectrolytic
capacitors;however,thisaloneisnotsufficienttopermitlargescale
deployment. Besidescost,inverterperformanceandfunctionalitywill
becomeanincreasinglyimportantfactorwithhigherlevelsofpenetrationofrenewableelectricityon
thegrid. BettercommunicationsandfunctionalitywillrequireradicallydifferentarchitectureforPV
powerelectronics.
Approachestomajorimprovementsinpowerelectronicsfallintotwocategories:(1)majorredesignsof
existinglargescaleinverters,and(2)developingsmallunitsthatcanbemassproducedandattachedto
individualmodules.
Majorredesignsofexistinglargescaleinverters:
ExistingMWscaleinvertersemployhighvoltagesiliconswitchesandlargemagnetictransformers. The
highvoltagesonthetransmissionsideoftheinverteraremanagedthroughacombinationoflarge60Hz
transformersandstackedsiliconswitches. Advancedhighvoltage,highfrequencyswitchcomponents,
lowlossmagneticmaterials,andnovelcircuitarchitectureshavethepotentialtosignificantlyreducethe
sizeandcostofMWscaleinverterswhilesimultaneouslyincreasingtheoverallefficiency.
Forexample,widebandgapsemiconductorssuchasSiChavethepotentialtoswitchat13kVwith
frequenciesashighas50kHz. Thehighervoltagereducesthepackagingcostandcomplexityofthe
system. Thehigherswitchingfrequenciesdramaticallyreducethesizeandcostofthetransformer
becauseforfixedimpedance,theinductancescalesinverselywiththeswitchingfrequency. Advanced
magneticmaterials,suchasnanocrystallinecompositeswithlowelectricalconductivityandlow
hysteresis,canenableswitchingfrequenciesthatare1001000timeshigherthanemployedtoday.
Scalingtheswitchingfrequencyfrom60Hzto50kHzcanallowthecoretransformertoscalefrom8,000
lbs.tolessthan100lbs.
Powerelectronicsattachedtomodules:
Electroniccomponentsandcircuitarchitecturesthatcanbeembeddedinthemoduleframewouldallow
maximumpowerpointtrackingtooccuratthemoduleorsubmodulelevel. Theresultingmodules
wouldbemoretoleranttopartialshading(allowingforpotentiallydenserinstallations)andcould1)
Figure11:Exampleofa
failedelectrolytic
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routepoweraroundsuboptimalmodulesorcells(improvingsystemavailabilityandmitigating
reliabilityofindividualcells),and2)directlyproduceACvoltages(simplifyingresidentialinstallation
whileincreasingthesafetyandreliability).
Onepossibleapproachwouldbetocreatemoduleintegrated
powerelectronicswhereadvancedsemiconductorswouldneed
tobeintegratedwithbeyondstateoftheartmagneticand
dielectricmaterialstorealizelowcost,smallformfactor,batch
manufacturedpowerconvertersthatcouldpotentiallybe
installedoneachmodule(Figure12). Theseelectronicswould
requireadvancedsemiconductormaterialsthatcouldwithstand
hightemperatures(100Cbackskintemperatures)andmaintain
highfrequencyswitching.
Thesameapproachofhigherinternalswitchingfrequencythat
wasdiscussedforutilityscaleinverterscouldalsobeappliedto
moduleintegratedpowerelectronics. Suchanarchitecture
wouldpermitmodulestobeeasilyconnectedandimprovethe
overallenergyefficiencyofthesystembyallowingeachmicroinvertertofrequencymatcheach
module.
Figure12:Microconvertersoneach
modulepromotebettercommunication
andfunctionalityamongstmodules.
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AppendixF: ChallengesforCostReductioninArrayProduction
SolarPVtechnologieshave,todatemadesignificantprogressreducingthecostofmodulesbuta
detailedanalysisofthefutureofcrystallineSiliconandCadmiumTelluridecellssuggestthattheyare
unlikelytomeetthetargetpricesgiventechnologiesdrivingcurrentlearningcurves. Thefigurebelow
showsthatcrystallinesiliconmodulepricescouldreacharound73centsperwattpricesiftheyareable
toachieve80%ofthetheoreticallimitofsinglecells(29%)andifwaferthicknesscanbereducedto80
microns(theyareabout180micronsthicktoday).
CadmiumTelluridemoduleshaveachievedsharppricereductionsandareonapathofcontinuouscost
reductiondriveninpartbycontinuousimprovementsinefficiency. Currentcellshaveanefficiencyof
approximately11%butefficienciesof17%havebeenachievedinthelaboratoryandtheoretical
efficiencies
are
approximately
29%.
The
experience
of
the
past
few
years
suggests,
however,
that
efficienciesabove11%areextremelydifficulttoachieveinpracticeandtherateofefficiencyincreases
hasslowedconsiderablyinrecentyears. Makingtheoptimisticassumptionthatefficienciescanreach
14%whilethecostofproducingaunitofarrayareadeclinesby26%,arraypriceswouldstillbearound
63centsperwatt.
Neartheoreticallimits:~24%efficientcells;low
($32/kg)siliconprice,80micronkerflesswafers
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Figure13QuarterlyreportedmoduleefficienciesfortheleadingCdTemanufacturerFirstSolarsuggeststhatsignificant
innovationisrequiredtocontinuetoadvancethetechnology.
Figure14:GlobalsolarPVmodulepricetrend:siliconwaferbasedandCdTe,historicandshorttermforecast19
19Sources:Mints,Navigant;BloombergNEF;FirstSolarEarningsReports;NRELinternalsiliconPVcostmodel
Costreductionnecessarytoachieve
$0.52/Wcost($0.63/Wprice)at
14%efficiencyrequiresa26%
reductioninmanufacturingcosts
whileincreasingefficiencyby32%
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Nevertheless,pastperformanceisnotnecessarilyanindicatoroffutureprogress. Thetrendofmodule
pricesdepictsthecompositeimpactofseveralcomplicatedfactors,includingforexample:
manufacturingefficiencies,economiesofscale,andinnovation.20 Asthesetechnologiesmature,the
contributionofmanufacturingefficienciesandeconomiesofscaletofurthercostreductionswill
diminish. Theimportanceofcontinuedandimpactfulinnovationswillbecomecriticaltomaintaining
thehistorictrend.
ForcSi,withoutnewmoduleencapsulationmaterials,costswillreachanaturalasymptotedefinedby
thecostofcommoditymaterialslikeglass(asymptote,orlowerlimitofcurrentcSimodulecosts
depictedinFigure14bybluedashedline).
ForCdTe,theleadingthinfilmtechnology,furthercostreductionwillrequirehigheraveragemodule
efficiency,expectedtoreachover14%by2014basedonaroadmapprovidedbyFirstSolar. Whilethe
pathwaytothisgoalisknownandinvolvestechnicalinnovations,implementingtheseinnovationsina
highvolumeproductionscenariowillbechallenging. Greaterchallengesexisttoincreasethis
technologysefficiencybeyond14%,suchasimprovingthelifetimeoftheabsorberlayer. Itisgenerally
believedthatinordertoimprovethequalityoftheabsorber,thegrainsizewillneedtobeincreased.
Onewaytoaccomplishthisistoslowdownthedepositionprocess,butthishastheundesirableeffect
ofincreasingthecost. Innovationinmaterialstechnologyisrequiredtoeliminatethistradeoff.
Ifweassumeabreakdownbetweencapital,materials,andlaborfollowingtheproportionsprojectedfor
atypicalcSimodulein2016,giveninTable7,thenthis48centswillbecomposedof9cents/wattfor
capitaldepreciation,22cents/wattformaterials,and5cents/wattforlabor. Thisbreakdownprovides
furtherillustrationofthechallengestoreach$1/watttotalsystems. Forexample,assumingaseven
yeardepreciationperiod,initialcapitalcostswillneedtobeontheorderof63cents/watt,
approximately50%betterthanFirstSolarsand25%to33%ofcurrentwaferedsilicon.
Formaterials,ifweassumeanextremelyambitiousmoduleefficiencyof29% theShockleyQueisser
limitofwaferedsiliconthe22cents/wattwouldbeequivalenttoanareacostof$65/m2. Evenatthis
highefficiency,currentcommoditymaterialssuchcoverglass,substratesandbacksheets,silicon,silver,
aluminumframingcouldexceedthesystemsbudgetformodulecost. Atcurrentcosts,glasswithaTCO
andantireflectioncoating
mightspecificallytakeupas
muchas16%to25%ofthis
total,indicatingtheneedfor
cheapersubstratesand
coatingtechnology. Frames
andotherstructuralparts
mighttakeupasmuchas
25%ofthetotalindicating
20GregoryF.Nemet,Beyondthelearningcurve:factorsinfluencingcostreductionsinphotovoltaics,Energyand
Policy34(2006)3218323,August2005
2010Es t. 2016Proj
Cost Cost Cost($/W) Cost($/m2)
Capital $0.20 $0.20 $0.09 $27
Materials $0.79 $0.49 $0.22 $65
Labor $0.09 $0.12 $0.05 $16
Margin $0.62 $0.24 $0.11$1.70 $1.05 $0.48
$1/WTarget
Table9:DetailedcostbreakdownforcSiPVmodule($1/WTargetassumes29%
efficiency)
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theneedforframeless,possiblyflexiblemoduletechnology. Goingtowardflexibleorotherlightweight
structuralmoduleapproachescouldalsosignificantlyreduceshippingcosts,currently8centsto10
cents/watt.21
Table9assumessignificant
potentialcostreduction
throughproductionmodels
thatcondensethesupply
chain. Waferedsilicon
modulescurrentlyhaveas
manyasfourdifferentsteps
inthesupplychain
(polysiliconprocessing,wafering,cellproduction,andmoduleassembly),eachextractingaseparate
marginwhichaddscosttothefinalproduct. Whiletherehasbeensomeattemptsatintegration(mostly
throughcombiningpolysiliconprocessingand/orcombiningwaferingandcellandmoduleproduction)
therehasalsobeencountertrendstowarddisaggregation. Movingtowardthinfilmtechnologiesthat
areinherentlymoreintegratedwouldsignificantlyreducemargins. FirstSolarforinstancebringsin
basicmaterialssuchasglass,depositiongases,andothermaterialsinoneoftheirfactoriesandships
outfinishedmodulesfromtheotherend. Thereiscurrentlynoanalogousproductionfacilityfor
waferedsilicon. Movingtheindustrytowardthinfilmtechnologieswouldalsocountercurrent
competitiveadvantagesofChinesewaferedsiliconmanufacturersandpotentiallycreatemore
opportunitiesforU.S.exports.22
SimilaranalysiscouldbedonetolookatthechallengeswiththeBalanceofSystems(BoS)and
Installationcostcomponents. ReferringtoTable10,installationlaborandoverheadtoinstallthe
$1/watt
system
would
be
approximately
19
cents/watt.
For
large
utility
systems,
only
one
fifth
of
the
laborisformechanicalinstallationwiththemajoritybeingforelectricalconnections. Thisindicatesthat
thereexistsanopportunitytoreduceinstalledcoststhroughefficientcomponentdesign. Forexample,
microinvertorsintegratedintoeachmodulemightbedevelopedtoexploitnewinnovativeconnection
schemesthatreduceelectricalinstallationlaborcosts. Otherpathsforcostreductionmightinclude
havinglargerpanels,potentiallyinstalledasrollsofflexiblematerial,withmanyoftheelectrical
connectionsintegrated.
21NRELAnalysisinternalmemo,SolarManufacturingCostModels,AlanGoodrich,April29,2010.
22Asia:65%siliconwaferglobalmarketshare;CompanyproductioncapacitiesSiliconforSolarCell,RTS
Corporation,September2009
2010 2016Proj
Cost Cost Cost($/W) Cost($/m2)
Mounting,Wiring,Other $0.87 $0.38 $0.17 $50
InstallationLabor,OH,othe $1.10 $0.41 $0.19 $54
Permitting,Design,Mgt $0.23 $0.18 $0.08 $24
$2.20 $0.97 $0.44
$1/WTarget
Table10:DetailedcostbreakdownforBOS/Installation($1/WTargetvalues
assumes29%efficiency)
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AppendixG:PreliminaryanalysisofEfficiency,Cost,andReliabilityBarriers(Table11)
FollowingtheexampleoftheSematechroadmap,theabovetable,dividesproblemsintofour
categories:
Manufacturablesolutionsexistandarebeingoptimized
Manufacturablesolutionsareknown
Interimsolutionsareknown
ManufacturablesolutionsareNOTknown
ForCPV,targetis 35%Module,currently
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AppendixH: TheneedforGovernmentfunding
Venturecapitalandotherprivatecapitalsourceshavefueledsignificantgrowthinthedevelopmentand
manufacturingofPVandothersolartechnologiesoverthelast5years,asshowninFigure15. These
investmentsfocusedlargelyontechnologiesthatcouldbecommercializedin2to4years,inorderto
respondtogovernmentincentiveprograms. Thistrendhaspeaked,however,and,asshownfor2009,
overallVCandprivateequitycapitalinvestmentsinsolararedecreasing. Thisisduetothecurrent
economicconditionswhichhavelimitedopportunitiesforprivatecapitalsourcestoexittheir
investmentsthroughpublicmarkets,alsoshowninFigure15. Thedevelopmentofsolartechnologiesis
capitalintensiveandmanyprivatecapitalsourcesarefocusedonseeingtheirexistinginvestments
throughtomaturityratherthanconsideringnewinvestments. Theseandotherfactorshavetherefore
limitedtheavailablepoolofprivatecapitaltoinvestinthenextgenerationofsolartechnologies.
ThecurrentenvironmentthereforeprovidesaneedandanopportunityforFederalR&Dfundingtofilla
gapinthesolartechnologyinvestmentpipeline. TheFederalgovernmenthasplayedthisrolebeforein
launchingthecurrentsolartechnologyindustryaswellasothernewindustriesinelectronicsand
biotechnology.
Inadditiontoaddressingtheadministrationsenergyandenvironmentalgoals,aninvestmentbythe
Federalgovernmentthattargetstheutilizationofthecountrysextensiveresearchandmanufacturing
infrastructurewillcontributesignificantlytowardsexportandeconomicgrowthinitiatives. Itis
Figure15: USCapitalInvestmentsinSolarEnergy
$0
$500
$1,000
$1,500
$2,000
$2,500
$3,000
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009TotalU.S
.Investment(MillionsNominal$)
Year
Solar Public Equity Activity
VC & PE Investments
TotalInvestmentIncrease
33%CAGR 20002009
36%CAGR 20002005
30%CAGR 20052009
U.S. Capital Investments in Solar Energy
-
8/7/2019 $1 Per W Photo Voltaic Systems
28/28
U.S.DepartmentofEnergy
AdvancedResearchProjectsAgencyEnergy EnergyEfficiencyandRenewableEnergy
estimatedthatby2012,andassumingstandardsolarPVcosttargetsandglobaldemandprojections
exportopportunitiesthroughoutthesolarPVsupplychainwillexceed$18.0billion.23
Othercountries,includingChinaandMalaysiahavemadearenewedcommitmenttotheirnationssolar
PVindustry,attractingglobalmanufacturers,includingcompanieswhosetechnologieswere,insome
cases,atleastpartiallydevelopedatUSinstitutions.
23NRELanalysismemoinsupportofthePresidentsNationalExportInitiative,SOLARENERGYTECHNOLOGIES:
USExportOpportunities,May2010