ESMAP MENA Local Manufacturing Chapter 1

7/29/2019 ESMAP MENA Local Manufacturing Chapter 1

1/60

C h A P T E 1

Review of CSP Technologies

Thischapterdescribesthetechnologiesofconcentratedsolarthermalpower

(CSP)to provide thebasis forthe subsequentsocio-economic analysis

fortheMENA-economies.Section1.1givesageneraloverviewofCSP

technologies.Section1.2presentstheCSPmarketwithitsmaincommercial

andindustrialplayersalongthevaluechain.Insection1.3,themainmanufac-

turingprocessesaredescribed.Lastly,section1.4analyzesthecoststructureof

atypicalCSPplant.ParabolictroughplantsarethemostcommercialCSPtechnology,andamount

atpresentto94percentoftheCSPmarketandinstallations(CSP-Today,2010).

Thisiswhythefollowingsub-sectionsmainlyfocusonthistechnology.owever,

mostndingsapplydirectlyorinanalogyalsoforotherCSPtechnologiesbecause

oftechnologicalsimilarity.

1.1 Oeriew of te CSP Tecnologies

Inanutshell,CSPpowerplantsproduceelectricitybyconvertingconcentrated

directsolarirradiationintoenergy.nlikephotovoltaiccellsoratplatesolar

thermalcollectors,CSPpowerplantscannotusethediffusepartofsolarirradia-

tionwhichresultsfromscatteringofthedirectsunlightbyclouds,particles,ormoleculesintheair,becauseitcannotbeconcentrated..

Theprocessofenergyconversionconsistsoftwoparts:

Theconcentrationofsolarenergyandconvertingitintousablethermal

energy

Theconversionofheatintoelectricity

A Local Manufacturing Report 4-14-11.indd 9 4/14/11 6:32 PM


2/60

10 MENA Assessment of the Local Manufacturing Potential for Concentrated Solar Power Projects

Theconversionofheatintoelectricityisgenerallyrealizedbyaconventional

steamturbine(Rankinecycle).Concentratingsolarcollectorsareusuallysubdi-

videdintotwotypes,withrespecttotheconcentrationprinciple:

Line-focusingsystems,suchastheparabolictroughcollector(PTC)and

linearFresnelcollector.Thesesystemstrackthesunpositioninonedimen-

sion(one-axis-tracking),seeFigure1.2.Point-focusingsystems,suchassolar

towersorsolardishes.Thesesystemsrealizehigherconcentrationratiosthan

line-focusingsystems.Theirmirrorstrackthesunpositionintwodimen-

sions(twoaxis-tracking),seeSources:Abgengoa,2010andDLR,2010.

Figures1.1and1.2showreferenceplants;thecaptionsofthepicturesinclude

theapproximatedimensionsoftheplants.

Figure 1.1 line-Fusing Systems: left: rbi Trugh cetr: 64 Mwe er nt

Nevada Slar one; dimensins: cetr aperture with 5 m (Mrin, 2010).

Right: liner Fresne cetr: 1.4 Mwe nt pE1 in Muri, Spin; dimensins:

Reeier eight abe Mirrr Fie: 7 m (Nte, 2010)

Sources: Morin, 2010 and Novatec, 2010.

Figure 1.2 int-Fusing Systems: left: Sr Ter nt S10, 11 Mwe in Seie, Spin;

624 s-ce eistts, 120 m2 Eh, Fus the Sunight ont Reeier n

Tp f 100 m igh Ter (abgeng, 2010). Right: dish Stiring rttype

nts f 10 kwe Eh in amer, Spin; dimeter 8.5m (dlR, 2010)

Sources: Abgengoa, 2010 and DLR, 2010.

MNA Local Manufacturing Report 4-14-11.indd 10 4/14/


3/60

Review of CSP Technologies 11

1.1.1 Parabli rugh clletr ehnlgy

ParabolictroughtechnologyiscommerciallythemostadvancedofthevariousCSPtechnologies.Sincethe1980sandearly1990s,nineparabolictroughplantsthe

SolarElectricGeneratingSystem(SEGS)plants,withatotalcapacityof354

MWelhavebeeninoperationintheCalifornianMojaveDesertinthenited

States.Inthepastveyears,severaltroughplantshavebeenbuilt,suchasa64

MWelpowerplantnearBoulderCity,inthenitedStates,andseveral50MWel

powerplantsinSpain.Therstcommercialparabolictroughplantinstalledin

Spainwasthe50MWelplantAndasol1,whichincludesathermalstoragewith

acapacityof7.5hoursoffullloadoperation(Figure1.3).Anoverviewofthe

commercialpowerplantsthataredeveloped,builtandoperatedgloballyisavail-

ableatSolarPaces(2010).

Theparabolictroughcollector(PTC)consistsofareceiver,mirrors,ametal

supportstructure,pylons,andfoundations.Theparabolic-shapedandfacettedmir-rorsconcentratethesunlightontothereceivertube.Theparabolicshapeisusually

implementedbyfourmirrorfacets,consistingofglasssheets(4mmthick)whichare

thermallybentandcoatedwithareectivesilverlayer,withadditionalprotective

layersonthebacksideofthesilver.Theabsorberinsidethereceiverisrealizedin

theformofacoatedsteeltube.Thecoatingisspectrallyselectiveinthesensethat

Figure 1.3 rbi Trugh er nts ans 1 (frnt) n ans 2 (rer) in Spin

ith cpity f 50 Mw Eh n Strge Size f 7.5 Fu-l urs. The

er Bk n the Strge re in the center f Eh Sr Fie

Sources: SMI, 2010.



4/60


itabsorbsthesolar(shortwave)irradiationwellandemitsalmostnoinfrared(long

wave)radiation,whichreducesheatloss(ildebrandt,2009).Theabsorbertube

issurroundedbyanevacuatedglasstubewhichishighlytransmissiveforthesunlightduetoananti-reectivecoating.Theabsorbertubeandtheencasingglasstube

togetherarecalledthereceiver.Intodayscommercialtroughsystemstheentire

collectorincludingthereceiveristrackedaccordingtothemovingsunposition.

ThereareseveralinnovationsinPTCtechnologyunderdevelopmentorin

prototypestatus.Thecurrentdevelopmentsfocusoncostreductionsintheas-

semblyandproductionprocess(e.g.,automizedproduction),lightercollector

structures,newmaterialsforcollectorstructures(suchasaluminum),andnew

heat-transferuids(e.g.,moltensaltanddirectsteam).

ExamplesofinnovativeproductsandcompaniesincludetheelioTrough,us-

ingalargercollectorapertureandaslightlylargerabsorbertubewithadiameter

of8.9cminsteadof7.0cm(Riffelmann,2009);theSkytrough,usingahigh-

reectancepolymerlminsteadofglassmirrorsandanaluminumsub-structure

insteadofsteel(Brost,2009);andthenewmirrortechnologyegaexofXeliox

andAlmeco(Almeco,2010),usingastiffaluminumsandwichsub-structurewith

ametallicreector.Furtherdetailsontechnologicalimprovementsofparabolic

troughtechnologycanbefoundinATearney,2010.

1.1.2 Parabli rugh Pwer Plant SystemWrking Priniple and theoptin f hermal nergy Strage

Onemainadvantageofsolarthermalpowerplantsoverotherrenewablepower

technologies,suchasphotovoltaicandwindenergyconverters,istheoptionof

energystorage.nlikethe storageof electricenergy,thermal energystorageispracticallyandeconomicallyfeasiblealreadytoday,eveninlarge-scaleapplications.

Solarthermalpowerplantscanbeequippedwiththermalenergystoragewitha

full-loadstoragecapacityintherangeofseveralhours.sually,thestorageislled

duringtheday,andemptiedagainaftersunset,sothatelectricityisstillproduced

evenaftersunset.Thisallowsforplantoperationinconcordancewithloadrequire-

mentsfromthegrid,becauseinmanycountriesthereisanelectricitydemandpeak

aftersunset.Duringsuchdemandpeaks,electricitypricesareusuallyfarhigher

thanbase-loadprices,creatingaveryimportantaddedvalueofCSPandstorage.

ariousthermalstoragetechnologiesareinprinciplefeasibleforsolarther-

malpowerplants,basedondifferentphysicalmechanisms(suchassensible

heatstorage,latentheatstorage,andchemicalenergystorage),andbyapplying

differenttypesofstoragematerials(suchasmoltensalt,oil,sand,andconcrete).Thestoragematerialneedstobecheap,becauselargequantitiesarerequired.A

comprehensiveoverviewofstorageprinciplesandtechnologiessuitableforsolar

thermalpowerplantsisgiveninGil,2010andinMedrano,2010.Itshouldalso

benotedthatdifferentheattransferuids(TFs)usedinthesolareldrequire

andallowdifferentstorageoptions.

Thermalstorageisinprincipleapplicablenotonlytoparabolictroughpower

plants,butalsototheotherCSPtechnologies.owever,theonlypowerplants



5/60


thatareinoperationtodayusingthermalstoragearetheAndasolpowerplants

showninFigure1.4.TheAndasolplantsuseatwo-tankmoltensaltstorage;see

workingprincipleinFigure1.5.Itstoresheatbyheatingupamedium(sensibleheatstorage).

Whenloadingthestorage,thehotheat-transferuid,comingfromthesolar

eld,passesthroughaheatexchangerandheatsupthemoltensalt.Inturn,the

storageisunloadedbytransferringtheheatfromthesaltbacktotheheat-transfer

uid.Manyoperationstrategiesarefeasiblefortheoperationoftheplantand

thestorage.Themostcommononeistofeedprimarilytheturbinedirectlywith

theheatfromthesolareld.Wheneverexcesssolarheatisavailable,itisstored.

Otheroptionsmayalsoaimatstoringthesolarenergyfromthemorninghours

insteadofdirectlyconvertingitintoelectricity,andtherebyusingthestoragefor

shiftingratherthanformaximizingtheplantsoperationalhours.

1.1.3 cmpnents f Parabli rugh Pwer Plants

ThemaincomponentsofparabolictroughpowerplantsareshowninFigure1.5.

AmoredetaileddescriptionofthesinglecomponentscanbefoundinAnnexA

toprovidethebasisforthesubsequentanalysesofthemanufacturingprocesses,

ofthecostofcomponentsandprocesses,andofthepotentialtoproducecom-

ponentsinMENAcountries.

Theanalysisofthecomponentsisbasedonstateofthearttechnology,which

consistsofa parabolictroughusingthermaloilas heat-transferuidandthe

powerblock.Optionally,athermalenergystoragecanbeused(seeFigure1.4).

Figure 1.4 Sketh f T Tnk Mten St Sr Therm Energy Strge Embee nt

cS er nt



6/60


CSPinvolvesmanycomponentsandmuchlaborwhichcangeneratehighlocal

valueintheMENAregion.Thelargestshareofbothinvestmentandoperation

andmaintenancecostsrelatestothesolareld(seesection1.4).Thepowerblock

sideusesmostlyspecializedequipmentthatdoesnotdifferfromplantcompo-

nentsthatareusedinconventionalpowerstations.Apartfromcivilengineering

andbasicconstruction,worksareperformedbyafewinternationalplayers(see

Figure 1.5 cmpnents f rbi Trugh er nt re the Sr Fie n the

er Bk. optiny, Therm Strge cn Be ntegrte

Parabolic Trough Power Plant

Solar eld Thermal storage Power block

Receiver

Mirror

Support structure

Tracking

Piping

HTF (oil)

HTF pumps

Heat exchanger

Molten salt

Hot tank

Cold tank

Heat exchangers

Pumps

Turbine

Generato

Condenser

Pumps

Heat exchangers

Fossil boiler

(optional)

Cold tank

Balance of plant

Figure 1.6 Mirrrs, Reeiers, Supprt Struture, n iping fr cS nts

Sources: Morin, 2010; Castaneda, 2006; Estela Solar, 2010; NREL, 2008



7/60


section1.2).Thethermalstorageasanoptionalplantcomponenthasonlyafew

commercialinstallationsworldwidesofar.Themajorcostinthestorageisthe

saltitself(errmann,2004),whichcanbedeliveredbyafewcompanieswithaccesstotherawmaterials,suchastheChileancompanySM(SM,2010).

AsCSPpowerplantsaredesignedtolastforatleast20years(feed-in-tariff

contractsinSpainlast20years),stabilityofeachcomponentisessential.The

componentshavetoresisttheharshdesertclimatewithoutdegradation.

1.1.4 other cSP cnepts Linear Fresnel, Slar wer, and Slar Dish

Beyondthemostcommercialtroughtechnology,whichrepresents94percent

oftheinstalledCSPplantcapacitytoday(CSP-Today,2010),othertechnologies

arebecomingmorecommercialandwillprobablyincreasetheirmarketshares

inthenearfuture.

Linear Fresnel collector plants

LinearFresnelcollectors(LFCs)areavariationofparabolictroughcollectors.Their

maindifferencefromparabolictroughcollectorsisthatLFCsuseseveralparallel

atmirrorsinsteadofparabolicbentmirrorstoconcentratethesunlightontoone

receiver,whichislocatedseveralmetersabovetheprimarymirroreld.Thehorizon-

tallyalignedreectorsuseatglassmirrorsthatareslightlycurvedthroughelastic

bending.Eachmirrorlineisindividuallytrackedaccordingtothepositionofthesun.

Thereceiveralsoconsistsofalong,selectivelycoatedabsorbertube,withoutany

needfortheexiblehosesorrotatingconnectorsrequiredbyaparabolictrough.

DuetotheopticalprinciplesofFresnelcollectors,thefocallineisdistortedbyastigmatism(Mertins,2009).Thisrequiresasecondarymirrorabovethetubeto

refocustheraysmissingthetubeinasecondaryreectionontothetube.Another

conceptisbasedonseveralparalleltubesformingamulti-tubereceiver,thereby

increasingthewidthinsteadofusingasecondaryreector.

Comparedtotroughplants,commercialLFCtechnologyisrelativelynovel.

Severalprototypecollectorsandprototypepowerplantshavebeeninstalledinthe

pastfewyears,butnofullycommercialLFCpowerplantsareyetinoperation.

Novatec,however,iscurrentlybuildingacommercial30MWelpowerplantin

Spain.Severalconceptswithdifferentgeometricanddesigncharacteristicshave

beendevelopedbyanumberofcompanies,seeTable1.1.

ThemaindifferencesbetweentheFresnelconceptandtheparabolictrough

collectorinclude:

LFCsusecheap,atmirrors(620 /m2)insteadofexpensiveparabolic

curvedmirrors(2530/m2);furthermore,atglassmirrorsareastandard-

izedmassproduct.

LFCsrequirelessheavysteelmaterial,usingametalsupportstructurewith

limitedornoconcrete(makingforeasierassembly).

On-siteinstallationofLFCsispredictedtobefaster.



8/60


Wind loads are smaller forLFCs,which leads to easier structural stability,

reducedopticallosses,andlessmirror-glassbreakage.

ThereceiveronLFCsisstationary,whereasthetroughreceivermoveswiththe

entiretroughsystemaroundthecentreofmass.Thisnecessitatesexibleconnec-

tionstothepiping,whichistechnicallychallengingandmaintenanceintensive.

Thereceiveristhemostexpensivecomponentinbothparabolictroughcol-

lectorsandinLFCs;however,themirrorsurfaceperreceiverishigherinLFCs

thaninPTCs.

TheopticalefciencyofLFCsolarelds(referringtodirectsolarirradiationoncumulatedmirroraperture)islowerthanthatofPTCsolareldsdueto

geometricprinciples:Inordertoreachacertainsolarconcentration,theLFC

mirrorsarepackedmoredenselythaninPTCplants.Theadvantageofreduced

mirrorspacingisthatitrequireslessland;thedisadvantageisthatmutualmir-

rorshadingandmirrorblockingofthereectedsun-lightoccurs.Furthermore,

thesunraysarenothitting theLFCmirrorperpendicularly,which leadsto

cosinelosses.

Table 1.1 Dierent Concepts of inear resnel Collectors

Name of Company Aperture width Photograph Receiver Location

Novatec BioSol(Morin 2010)

12 m(16 mirrors of75 cm)

Single tubeabsorber withsecondaryconcentrator

1.4 MW plantin operation inCalasparra, regionMurcia, Spain

Fresdemocollector ofSPG and MAN(Bernhard 2009)

15 m(25 mirrors of60 cm)

Single tubeabsorber withsecondaryconcentrator

Demonstrationcollector atPlataforma Solarde Almera,Andaluca, Spain

Areva Solar(Areva 2010)

approx.20 m(10 mirrors of

approx. 2 m)

Multi-tubereceiver, nosecondary

concentrator

5 MWel

powerplant atKimberlina,

California, USA

PSE/Mirroxx(process heat


9/60


Itisexpectedthatthementionedcostadvantageswillmorethancompensate

fortheefciencydrawbacksofLFCtechnology,butthiswillhavetobeprovenin

commercialplants.LinearFresnelcollectorsseemtobemoreopenforredesignandadaptationtolocalconditions.Localcontentisprobablyhigherthanforthe

parabolictroughduetothesimplercomponents.AllcommercialFresnelcollectors

usepressurizedwater/steamasanenvironmentallyfriendlyheat-transferuid.A

powerplantwithdirectsteamgenerationthusrequiresfewerheatexchangers

thanoneusingTFthermaloil.

Solar Tower Plants

SolarTowerPlants,alsocalledPowerTowers(seeFigure1.7),concentratethedirect

solarirradiationontoatower-mountedreceiverwheretheheatiscaptured,typically

generatinghightemperatures.Thisheatdrivesathermo-dynamiccycle,inmostcases

awater-steamcycle,togenerateelectricpower.Thecollectorsystemusesahuge

numberofsun-trackingmirrors,calledheliostats,toreecttheincidentsunlight

ontothereceiverwhereauidisheatedup.Todaysreceivertypesusewater/steam,

air,ormoltensalttotransporttheheat.Dependingonthereceiverconceptand

theworkinguid,theupperworkingtemperaturesrangefrom250Cto1000C.

Therstcommercialsolartowerplant(seeFigure1.7)useswaterasthe

heat-transferuid(TF)andgeneratessaturatedsteamtopoweritsturbine.

Apromisingpre-commercialconceptthatiscurrentlyunderdevelopmentuses

compressedairastheheattransfermediumincombinationwithagasturbine

(Buck,2008).Inthiscase,thereceiverreplacesthecombustionchamberofa

conventionalgasturbine.Inthelongrun,highsolarefcienciesincombination

withacombinedcyclei.e.,acombinedgasandsteamturbinecyclearepos-sible.Thetypicalsizeofsolartowerplantsusuallyrangesfrom10MWelto100

MWel.Thelargertheplantsare,thegreateristheabsolutedistancebetweenthe

receiverandtheoutermirrorsofthesolareld.Thisinducesincreasingoptical

lossesduetoatmosphericabsorptionaswellasunavoidableangularmirrordevia-

tionduetoproductiontolerancesandmirrortracking.InadditiontotheSpanish

Figure 1.7 11 Mwe er Ter by abeng, unres f eistts cnentrte the Sun

(up t 500 Times) ont n absrber n the Tp f the Ter

Source: Abengoa, 2010.



10/60


companyAbengoaSolar,whichdeveloped,installed,andoperatesthesolartower

technologyshowninFigure1.7,severalnewsolartowertechnologieshavebeen

developedinthelastfewyearsandarecurrentlybeingproveninprototypepowerplantsbythecompaniesBrightSourceEnergy,Sener,eSolar,andAora.

Dish Stirling plants

DishStirlingplantsuseaparabolicdishconcentratormadeofreectorfacets

toconcentratedirectsolarirradiationontoaquasi-punctualthermalreceiver.

sually,aStirlingengineincombinationwithageneratorunit,locatedatthe

focusofthedish,transformsthethermalpowertoelectricity(seeFigure1.8).

TherearecurrentlytwotypesofStirlingengines:kinematicandfreepiston.

inematicenginesworkwithhydrogenasaworkinguidandhavehigheref-

cienciesthanfreepistonengines.Freepistonenginesworkwithheliumand

donotproducefrictionduringoperation,whichenablesareductioninrequired

maintenance.Multi-cylinderfreepistondevelopmentspromisecostreductionand

overallconceptsimplication.ThesizeofasingleDishenginetypicallyranges

from5to50kWel(Laing,2002).

Figure 1.8 Mrip dish Stiring Frm in arizn, the rk hs Rte er f 1.5 Mwe

cnsisting f 60 dish-Stiring nits

Source: Stirling Energy Systems, 2010, srpnet.com, 2010.



11/60


DishStirlingtechnologypresentsthe highestefciency (DirectNormal

Irradiance[DNI]onreectorareatopowergeneration)amongCSPsystems.

StirlingEnergySystems,togetherwithSandiaNationalLaboratories,achieveda

newworldrecordofsolar-to-gridsystemconversionof31.25percent(Taggart,

2008).AbenetofDishStirlingtechnologyoverotherCSPmodelsisthedrycool-

ing1thatisusedinmostconstructions,enablingelectricalsupplyinaridregions.

AnotherclearadvantageoverparabolictroughandlinearFresneltechnologiesis

adaptabilitytoslopes.ACSPpowerplantofMWscalecaneasilybeinstalledin

amountainousregionliketheGreekislands.Thesetwopointsdrycoolingand

adaptabilitytomountainousregionsarethemajoradvantagesofDishStirling,

openinganeconomicallyvaluablenichetothismodularscalabletechnology,even

thoughthelevelizedcostofelectricityisstillhigher.Anotherreallyinteresting

areaofapplicationisthereplacementofdieselenginessupportingminigrids.

SincethedishStirlingconceptisbasedonamodularscalableenergyoutput,it

presentsanidealrenewablealternativetorelativelyexpensiveandoil-demanding

dieselenergysupply.InthenitedStates,largescalecentralizedpowerplantsinthepowerrange

ofseveralhundredMegawatts,consistingofthousandsofDish-Stirlingunits,were

announcedmanyyearsago,buthavenotyetbeenproduced.

Figure 1.9 Gb cS cpity Existing n thrugh 2015

Source: Estela, 2010*.

* The CSP operational power tends to change quite rapidly, especially in Spain and the US: Protermosolar provided in

December 2010 the following gures: Spain Total operational 674 MW (Tower: 21 MW, Parabolic Trough 13x50 MW=650

MW, Fresnel+Stirling 3 MW), USA 505 MW(Parabolic Trough 354 + 64 + 75 MW = 493 MW, Fresnel + Stirling 7 MW, Tower

5 MW).

1DrycoolingconceptsalsoexistwithotherCSPtechnologies,butthestandardtechnologyisbasedonwetcoolingsystems.



12/60


1.1.5 Status f cSP Prjet Develpment

AftertwentyyearsofoperationintheSolarElectricGeneratingSystem(SEGS)plantsinCalifornia,theworld-widemarketgrowthofrenewableenergieshas

givenCSPtechnologyanewprospectiveincountrieswithhighdirectradiation.

StartingintheSpanishand.S.electricitymarkets,manyprojectsarenowunder

developmentandunderconstruction.Asparabolictroughplantsgainstatusas

acommerciallybankabletechnology,thistechnologyhasannouncedthehighest

shareofnewprojectsworld-wide(upto9000MW).owever,somenewprojects

havealsobeenannouncedusingCentralReceiverswithhighsolartowers,mainly

inthenitedStates.DishEnginesstillshowsomecostdisadvantages,but.S.

developershopetoovercomethesecostaspectsthroughmassproductionand

thousandsofsingleinstallationsinalargearea(totalcapacity8001000MW).

AlthoughFresneltechnologyhasasimilarsolarelddesignandmirrorswith

lowerproductioncosts,due toa late developmentof directsteamgeneration(DSG)about10yearsago,itisbehindinvolumeofannouncedprojects(therst30MWplantintheSouthofSpainwillcreatecommercialexperience).owever,comparedtothat,nosingleDSGprojectwithparabolictroughhasbeenannounced.Table1.2showsthesizeoftheCSPmarketaccordingtotheprojectstatusandliststhecurrentCSPprojectsintheworldmarketbyappliedtechnologies.Bythemiddleof2010over800MWofCSPplantswereinoperation(see

Figure1.9);the electricityproducingplantshaveconsequentlydoubled their

capacitywiththenewinstallationsince2007,aftertheinstallationoftheSEGS

plantsinCalifornia.Inallcategories,(operational,construction,andplanning

phase),parabolictroughtechnologyisleadingtheworldmarket,butthealterna-

tivesFresnel,solartower,andDish-Stirlingmightenter themarketquickly

afterfurthertechnologybreakthroughsandachievedcostreductions.ThetwomarketsintheSAandSpainarestronglydominatingtheCSP

market(seeFigure1.9).BasedonnationalsupportincentivesforCSP,themarket

hasshownaboominrecentyears.OthercountriesinMENA(seeFigure1.10),

Australia,andAsiaaredevelopingtheirrstprojects;ifimplementationissuc-

cessful,furtherprojectsareexpectedinallofthesecountries.

Thereare,however,somethreatstothesedevelopments,especiallyontwofronts:

Table 1.2 Current CSP Projects in te orld Mark

Operational

[M]

Under construction

[M]

Planning pase*

[M]Total

[M]

Tower 44 17 1,603 1,664

Parabolic 778 1,400 8,144 10,322

Fresnel 9 30 134 173

Dish & Stirling 2 1 2,247 2,250

Total 833 1,448 12,128 14,409

Source: Sun & Wind Energy 2010.* Planning phase: Projects are announced by project developers or owners. Pre-engineering is taking place, but real con-struction and all administrational authorizations have not been nished yet.



13/60


Duetothelong-termimpactsofthenancialandeconomiccrisis,alarger

numberofplannedinstallationsarenotbeingrealized.Thiscouldhamperthe

costdegressionofthetechnologyanditspenetrationintheMENAregion.

Otherrenewableenergysourcesshowfargreaterdynamics:bytheendof

2010,windenergymayhavepassedthe200GWlevelofinstalledcapacity,

photovoltaic(P)willreach32GW.AlthoughCSPisseenasacomplemen-

taryrenewableoptiontowindandP,thereisalsoanincreasingelement

ofcompetition,especiallywithP.

1.2 Structure and Caracteristics of International Players in te CSPvalue Cain

1.2.1 he cSP re alue chain

ThissectionprovidesanoverviewoftheexistingCSPvaluechain.Itwilldescribe

theinternationalCSPmarket,thekeyplayersincompletedandongoingCSPprojects,andtheCSPcomponentmanufacturingindustriesinthemainmarkets

(EuropeandthenitedStates).

TheCSPcorevaluechainconsistsofsixmainphases:

ProjectDevelopment

Materials

Components

Figure 1.10 MENa cS cpity: rjets uner opertin/nstrutin n in nning

hse*

Operation/construction Planning

0

250

InMWc

apacity 200

150

100

50

Morocco Algeria Egypt Jordan IranTunisia Israel Abu Dhabi

* Higher gures have been forwarded in some countries, e.g., 2000 MW in Morocco. This gure only includes planned

plants that are sufciently well documented, e.g., through calls for tender. It is not always clear how large the CSP sharein those plans could be.

Installed capacity () End 2009 Mid 2010 End 2010

Wind energy 159,2 175,0 200,0

Photovoltaic (PV) 22,9 32,0

CSP 0,8

Sources: World Wind Association 2010 (http://www.wwindea.org/home/index.php); S olarbuzz 2010 (http://www.solarbuzz.com/)



14/60


PlantEngineering&Construction

Operation

Distribution

Therearealsothreecross-cuttingactivities,whicharenotdirectlypartofthe

valuechain,butratherserveasuperordinatefunction.Theysupporttheproject

fromthebeginningtotheendoraccompanythetechnologydevelopmentand

specicationsovermanyyears:

Finance&Ownership

Research&Development

PoliticalInstitutions

In addition,these cross-cutting activities also offerprospects for local

employment.

Project development

TherstphaseofaCSPprojectistheprojectdevelopment.Thedecision-making

processbeginswithtechnicalandeconomicfeasibilitystudies,thesiteselection,

andnancingopportunities,whichprovidethebasicscopeoftheproject.After

drawinguparstdraftincorporatingthesebasicdecisions,theconceptualen-

gineeringoftheprojectstartswithaproposalforthetechnicalspecications.

Oncetheconceptualdesignisestablished,thepermissionprocessandcontract

negotiationscanbegin.Thesephasesarecloselyinterlinkedwiththenancingof

thewholeproject.Incurrentprojects,engineeringexpertsspecializinginpowerplantprojectsofferalltheservicesneededfortheprojectdevelopment.Oftenthe

projectdevelopmentphasetendstobethelongest,duetothefactthatfeasibility

studies,thepermissionprocess,andpublicdecision-makingprocessestakealot

oftime.Typically,betweenoneandthreeyearspassbetweenthersttenderand

thenalprojectstart(FichtnerSolarAG2010andSolarMillenniumAG2010).

Materials

ThesecondphaseoftheCSPcorevaluechaininvolvestheselectionandgathering

oftherawmateralsandfurthertransformedmaterals.Whilesomematerials

areprovidedbytheworldmarket,othersaresuppliedlocally,dependingoncosts

andlogisticalaspects.uantitatively,concrete,steel,andglassarethematerialsmostneededforaCSPplant.Fora50MWreferenceplant,forexample,about

10,000tonsofconcrete,10,00015,000tonsofsteel,and6,000tonsofglassare

required.FortheuraymatplantinEgyptaswellasforplantsinSpain,concrete

andsteelhavebeenprovidedbylocalsuppliers.Thesearethematerialsprincipally

requiredforaCSPplant:glassforthemirrors,steelforthemountingstructure,

chemicalsfortheheat-transferuid(TF),andinsulatingmaterialstogether

withdifferentmetalsforthepiping.



15/60


Figure1.1

1

BsiStrutureofthecSpvluechinnludingcros

s-cuttingatiities

Project

Development

Concept

Engineer

ing

Geographical

Determin

ation

Determin

ation

ofgeneral

requirem

ents

ConcreteSteel

Sand

Glass

Silver

Copper

Salt

Other

chemicals

Mirrors

Mo

unting

Str

ucture

Receiver

HT

F

Co

nnection

pip

ing

Ste

amg

enerator/

heatexchanger

Pumps

Sto

rageSystem

PowerBlock

Gridconnect

EPC-Contractor:

Detailed

Engineering

Procurement

Construction

Operation&

maintenanceof

theplant

Utility

Transport&

distributionof

electricity

Materials

Components

Finance&Ownership

Research&Development

PoliticalInstitutions

Plant

Engineering

&Construction

Operation

Distribution

Core

value

chain

Essential

partners

Elements

ofthe

core

value

chain



16/60


TheGermanAerospaceCenter(DLR)comparedthematerialsrequiredfor

differentCSPtechnologies(iehbahn,2008).Thematerialneedswerenormal-

izedto1MWelinplantsizeand1hourofthermalstoragecapacityinorderto

balancetechnologyspecics(suchasdifferencesinefciency),seeFigure1.13.

LikeTable1.3,Figure1.13showsthatthestoragesystemaccountsforalarge

portionoftheusedmaterial.Thisistrueforallshowntechnologies,despitethe

relativelysmallassumedstoragesizeofonehour.Thesolartowerplantusesa

Figure 1.12 rjet deepment f cS nt

Commis-

sioning

and test

period

Request forAdministrative

Authorization

Public

Information

ObtainingAdministrative

Authorization

Request forProject

Approval

PreliminaryBasic

Engineering

Construction

contracts

Supply ofequipment-

construction

Environmental

impact analysis

Consultation

to aected

entities

Construction

Permits

Basic

Equipment

Purchase

In-Depth

Engineering

Responses

to this

publication

Reply to

responses

Maturing Period: 1824 months Execution Period: 1833 months

Source: Fraunhofer ISE.

Figure 1.13 cmprisn f cmpnents f the Bsi Sr Therm er nts, Se

t 1 Mwe n one ur f Strge cpity

Solar eld Buildings Storage system Operating

0

1500

Kg

1000

500

Parabolic

Trough

HTF thermooil

MS storage

1MWh

Central Receiver

HTF molten salt

MS storage

1MWh

Parabolic

Trough

HTF thermooil

concrete storage

1MWh

Parabolic

Trough

HTF direct steam

PCM storage

1MWh

Frensel

Trough

HTF direct steam

PCM storage

1MWh

Note:The combinations of collector and storage technologies shown in Figure 1.13is exemplary. The molten salt storage

(MS) is the only commercial storage technology shown. The storage systems based on concrete and phase changematerial (PCM) is at prototype status, today.



17/60


higherfractionofbuildings(duetothetoweritself).ThelinearFresneltechnol-

ogyusesstrikinglylittlematerial.Thisisbecauseofaverylightcollectordesign,

butalsobecauseoftheabsenceoftheheavyconcretefoundationsusedforall

othertechnologiesshown.

Components

Thissectiondescribesthe components,thethirdphase inthevaluechain.

Conceptually,aCSPplantcanbedividedintotwoparts:thesolareldandthe

traditionalpowerblock.Thekeycomponentsofthesolareldarethemetal

supportstructureforthemounting,themirrors,andthereceivers.SincetheCSP

marketworldwideisstillataveryyoungstage,onlyafewcompaniesexistwhich

cansupplythesecomponents.

Solar Field of CSP Plant

Themetalsupportstructureismadeofsteeloraluminumandisprovided

bytraditionalsteelandaluminumcompanies.Thestructurehastomeet

certainrequirementsforthestructuralstabilityagainstwindloadsinorder

toensuretheprecisealignmentofthemirrorsovertheentirelengthofthe

collectorrow,whichcanreachupto150meters.

MirrorsfortheCSPindustrycanbeeitherat(towers,linearFresnel)or

bent (parabolic trough, dish).Bendingandmirrorcoatingarestandardprocessesoftheglassindustry,andcanessentiallybeperformedonstan-

dardequipment.Mirrorshavetobehighlyprecise.Evenmarginalreec-

tionlossesofdirectradiationleadtoalowerdegreeofelectricalefciency

andthereforejeopardize theeconomicefciencyofthewholeproject.

CommerciallyviableCSPmirrorplantsmusthaveaminimumcapacity

(morethan200400MWelequivalentsperyear).Typicalglassandmirror

companieshaveawiderangeofcustomersinmanyindustries,e.g.,automotive

Table 1.3 Material and and equirements for CSP eference Plant

Parabolic Trough Plant50 MW with 7 hours storage

Steel 10,00015,000 tons

Glass 6,000 tons

Storage Medium (Salt) 25,00030,000 tons

Concrete 10,000 tons

Insulation Material 1000 tons

Copper* 300 tons

Land 2 km

Source: Author.* Personal communication from Protermosolar. Although this gure is lower than for other materials, copper has a muchhigher value than other materials; for example, it has10 times the value of steel at present.



18/60


glass,technicalglass,solarmirrors,anddifferentkindsofspecial-purpose

glass.AccordingtoGuardian,thelevelofcomplexityforsolarproducts

iscomparabletoautomotiverequirements(shapesaremorecomplexintheautomotivesegment,butgeometricspecicationsarestricterforsolar

mirrors).Althoughrawatglassandmirrorsaretradedglobally,thecost

oftransportingheavyitemsinacompetitiveindustryisabarrier;locating

mirrorproductionnearconsumptioncentersisthereforelikelytohappen

oncemarketsreachedsufcientsize.

Receiversarethemostcomplexpartofthesolareld.Theyhavetoabsorb

asmuchlightaspossiblewhilereectingaslittlethermalenergyaspos-

sible.Thetransitionfromglasstometalhastohavethesamecoefcientof

thermalexpansion.eryfewcompaniesworldwideproducethisspecic

component.Thesteelinreceivershastobespecicallyselectedforgood

durabilityand compliancewith coating requirements.This steelwould

imposestrongrequirementsonlocalproduction.

Mirrors,receivers,andthemountingsupportstructurerepresentthemain

elementsofthesolareld.Inaddition,animportantroleisplayedbytheheat-

transfer-uidsystem,whichincludestheheat-transferuid(TF),thepiping,

insulationmaterials,andpumps.

InmostofthecurrentCSPplants,thermaloilisappliedastheTF.Itispro-

ducedbylargechemicalcompanies.Approximately13tonsperMWeinstalled

powerareneeded.Insulationmaterial(about20tonsperMWe)iswidelyused

andconsequentlyalargenumberofproducerscanbeidentied.Thequalityof

theinsulationishighlyimportantasitdirectlyinuencesthethermalefciency,

andconsequentlytheplantoutput.SomeCSPprojectsaretryingtousemoltensalt,whichentailssometechnicaladvantages(largestoragecapacity)butacouple

ofdisadvantagesaswell(e.g.,freezingofsalt).

InaCSPplant,thehydraulicpumpsthatcirculatetheoilormoltensaltin

the20kmto200kmlongpipingsystem,andtheheatexchangersthattransfer

thethermalenergyintosteam,arerathercomplexandexpensivecomponents.

Internationalcompanieswithalargedegreeofknow-howinthissectorprovide

thesecomponents.SomepublicationsincludetheTFsystemsaspartofthe

solareld;othersdisplayitseparately,aswillbedoneinthisstudy.

Electricalcomponents,electroniccables,andhydraulicadjustmentunits(for

mirrors)usedinthesolareldandthepowerblockforalladjustmentandcontrol

processeshavetobepreciseandofgoodqualitytoassureaplantlifetimeofat

least25years.

Power block of CSP plant

Thekeycomponentofthepowerblockisthesteamturbine.Technically,turbines

couldbeconsideredthemostcomplexanddifcultpartofaCSPplant.Normally

turbinesaremanufacturedbybigindustrialcompanieswithlong-termexperience

intheeld.Duetotheextremelyspecializedrequirementsofturbines,shipping



19/60


costsareirrelevantandsupplierscanbefoundallovertheworld.Thepower

blockusedforCSPisverysimilartothatusedforcombinedcyclepowerplants.

ThegridconnectionisorganizedandfullledbytheEPCcontractororothersubcontractorsthatbuildtheaccessto the localandregionalpowergrid.By

meansofstandardizedsubstationsandtransformers,thesystemisconnectedto

themediumvoltageorhighvoltagegridforlargertransmissiontothenalend

consumer.

Engineering and construction

Thefourthphaseofthevaluechaininvolvestheplantengneerng&construc-

ton.Thisisperformedbytheengineering,procurement,andconstruction(EPC)

contractor.TheEPCcontractorisresponsibleforthewholeplantconstruction.

Asprojectmanager,heselectsallthesuppliersandawardsmostofthejobsto

subcontractors.Sometimes,evenbeforethecontractingentitychoosesthenal

EPC,candidateshavealreadychosencertaincomponentsuppliersduetologisti-

cal,time-sharing,orpoliticalmotivations.Normallyallcomponentsuppliersas

wellasthesubcontractorswhocarryoutthedetailedengineeringandthecivil

worksarechosenbytheEPCcontractor.Themaintaskoftheprojectmanager

istocoordinateallpartners.EPCcontractorsareusuallysubsidiarycompanies

ofindustrialgroupsandcanresorttobuildingcompaniesandengineeringcon-

sultantsintheirowncompanygroup.Thecivilworksforthetotalplantarealso

oftencloselyconnectedtotheEPCcontractor,asmanycompanieshavetheir

ownsubsidiariesorjointventurestoundertakethesetasks.Largeinfrastructure

companiesforbuildings,powerplants,andotherinfrastructureprojectsprovide

thebasic services forcivilworks, such aspreparingthe ground, building thesupportinginfrastructure(streets,houses),andcreatingthefoundationofthe

powerplant.Forthesecivilworks,andfortheassemblyandinstallationofthe

collectors,alargenumberoflowskilledworkersisrequiredontheconstruction

site.Forexample,ataSpanishpowerplant,500workerswereneededforthese

works.InNorthAfrica,duetolowerproductivity,thenumberofemployeescan

increasetoupto10001200.EPCcontractorshaveoftenbeengeneralcontrac-

tors,buildingdifferentkindsofplantsandindustryprojects,formanyyears;they

thereforehaveawiderangeofexperiencetodrawupon.Incurrentprojectsthe

EPCcontractorevenserves,inpart,asnancerandowner,andfortherstyears

isalsoresponsiblefortheoperationandmaintenance(O&M),whichbindshim

totheplant.

Operation

Thefthphase,Operaton,includestheoperationandmaintenance(O&M)of

theplantforupto2530years.Thisisoftenperformedbylocalsub-contractors

and,asmentionedbefore,sometimescoordinatedbytheEPCcontractorsinthe

rstyears.Currently,about30peoplearenecessaryfortheoperationand10

peopleforthemaintenanceofa50MWCSPplant(seeTable1.10).Thetasks



20/60


foroperationandmaintenancecanbesplitintofourdifferentgroups:Plantad-

ministration(6workersneeded),operationandcontrol(13),technicalinspection

ofthepowerblock(7),andthesolareldoperationandmaintenance(14).Forbiggerplants,theO&McostperinstalledMWdecreases(IEA2010Roadmap).

Distribution

Thesixthandnalphase,the strbuton,involvesdeliveringtheelectricity

fromtheplanttotheconsumers.Largeutilitycompaniestaketheresponsibil-

ityforthedistribution.InthenitedStates,theselargeutilitiesareobligedto

buyorproduceacertainamountofsolarelectricitybytheRenewableStandard

Portfoliosofeach.S.state.

Finance & ownership and political institutions

Twoofthecross-cuttingactivitiesareabsolutelycrucialfortherealizationofa

CSPproject:Fnance&OwnershpandPoltcalinsttutons.

SinceCSPprojectsarestillnotprotablewithoutnancialsupport,theproject

nancingisoftenthemostdifcultpartoftheprojectdevelopment.InSpain

forexample,feed-intariffsensurethepayment.Basedonthefeed-intarifflevels

andspecications,privateinvestors,togetherwiththeprojectdevelopers(which

canbewithinthesamecompany),calculatetheprotabilityofaproposedplant.

Thissupportmechanismimprovestheprocessofmakingtheprojectbankable

becauseofthelong-termguaranteesandcontinuousrevenueowstotheowners

andconsequentlytothecreditors.

owever,ifthetariffsarestaticallysettoogenerouslyoveralongerperiodoftime,thecountrycannotcontrolthenumberofplantsconstructed,asithap-

penedinSpaininthePmarket.InNorthAfricasocalledPPA(powerpurchase

agreements)areoftenusedtoassurenancing.InaPPA,thestatecontrolsthe

numberofplants,andeveryplantistenderedseparately.Thisleadstoindividual

conditionsforeveryplantconstructed,butdoesnoteasilypromoteadynamic

marketevolution. Inpractice,differentkindsofownership structurescan be

found.Therearethreecommonoperatormodelsinthecontextofpowerplants:

Build-Own-Operate(BOO),Build-Own-Transfer(BOT)andBuild-Own-Operate-

Transfer(BOOT)(DanielBeckmann2003).

InaBOO,theprivatesectornances,builds,owns,andoperatesafacilityor

servicepermanently.Intheoriginalagreement,requirementsofthepublicsectorarestatedandtheregulatoryauthoritytakescontrol.

TheBOOTcontractenclosesanaltransferoftheplantownershiptothe

governmentortoanotherentityatapreviouslyagreed-uponpriceorthe

marketprice.

ComparedtotheBOOTcontract,aBOTagreementstartsthetransferto

thegovernmentatanearlierpointoftime(5yearsinsteadoflongerperiods

of20to30yearsforBOOTcontracts).



21/60


Existingnancingandownershipstructuresdemonstratethehighlevelof

importanceheldbypoliticalinstitutionsinbuildingCSPplants.Currently,CSP

technologiescanonlybedevelopedwithpoliticalsupport.Withtime,morecoun-triesarerecognizingthisandjoininginprovidingnancialsupporttoCSP.For

example,Spainhashadafeed-intariffsince2003;somestateswithinthenited

StatessupportCSPwithrenewableportfoliostandards;Moroccohasannounced

anationalsolarplan;andIndiahasintroducedafeed-intariffforsolarenergy.

Research & development

Research&development(R&D)isacross-cuttingissueandaveryimportant

aspectfortechnologicalprogressandfastmarketentry.Tobringthetechnology

forward, projectpartnersmustwork closelywith researchinstitutions.R&D

plantsplayalargerolehere.ExistingR&Dplantsincludethesolartowerinlich

(Germany)andthePlataformaSolardeAlmera(PSA)inSpain,wheredifferent

CSPtechnologiesaretested.Inordertoreducethenalacceptanceperiodatthe

endoftheconstructionandcommissioningphaseofacommercialplant,new

methodologiesfortestingarerequired.Astandardizedtestingandmonitoring

procedureforinstalledsolareldswillbeanimportanttaskforallfutureprojects.

1.2.2 Internatinal alue chain

BasedontheCSPvaluechainpresentedabove,Figure1.14showsthemaininter-

nationalplayersinvolvedineachphase(eithercompaniesorotherstakeholders).

Someprojectsareledbylargeindustrialconsortiathatincludenewentrantson

theCSPmarket(suchaseoliaEnvironment,CNIM,andSaintGobain).Forasingle largeCSP investmentproject, aconsortium isformedunderanEPC

contractorthatsuppliesthecomponentsandservicesfortheconstructionofthe

plant.Afterasuccessfulcooperationinarstproject,existingrelationsbetween

thecompaniesareoftenusedtoconstructnewCSPplants.Overthelasttwo

years,severalmergersandacquisitionshavetakenplaceintheCSPindustry.

Someimportantmarketdevelopmentsinrecentyearsinclude:

In2006,SpanishAccionaacquiredthemajorityonSCSPcompany

Solargenix.

In2007,MANFerrostaalAGandSolarMillenniumAGfoundedthecom-

panyMANSolarMillenniumGmb,specializinginprojectdevelopment,

nancing,andconstructionofsolarthermalpowerplants.In2010,thisjointventurebecamepartofthecompanyFlagsolGmbwhichuntilthen

wastheengineeringsubsidyofSolarMillennium(100percent).Sincethis

merger,Flagsolbelongs75percenttoSolarMillenniumand25percentto

Ferrostaal.Inthemeantime(in2009),a70percentshareofFerrostaalwas

soldbytheGermanMANholdingtotheAbu-Dhabi-basedIPIC.

In2008,SenerandMasdarcreatedajointventure(Torresol)fortheircom-

monCSPactivities.



22/60


Figure 1.14 nterntin cS vue chin ith cmpnies/trs fr Eh Setr

ComponentsEPCProjectDevelop.

Materials

Valuechain

Storage

System

Power Block

& pumps

Grid

Connection

Mirrors ReceiverSupport

structure

Steam

Generator/

Heat

Exchanger

Connecting

Piping

Components

Companies

EPC

Operation Distribution

Operation &

Maintenance

Utility / Transport

DistributionValuechain

Companies

Finance &

Ownership

Research &

Development

Political

Institutions

Essentia

lpartners

Concept

EngineeringRaw & Semi-

nished

HTF

Valuechain

Companie

s

Abengoa Solar

Abengoa

Aries

Bright source

Epurone

Solar

Fichtner

Ibereolica

M+W Zander

Novatec

Solar Millennium

Stirling Energy

Systems (SES)

Torresol/

Masdar

BASF

DowChemicals

Linde

Solutia

Abengoa

Acciona

ACS Cobra

Flagsol

FPL Energy

Iberdrola

Nevada Solar

MAN Ferrostaal

APS

EETC

Endesa

ONE

Local banks

International

banks

World Bank

AfricanDevelopment

Bank

Investors

Public

institutions

Ciemat

DLR

Fraunhofer

NREL

PlataformaSolar de

Almeria

Sandia

National

Laboratory

Local

governments

Abengoa

Acciona ACS Cobra

Bharat Heavy

Electrical Ltd.

Bilnger

Berger

Kfer

GE Power

MAN Turbo Siemens

Sener

Flagsol

ABB

Alstom GE Power

Kraftanlagen

Mnchen

MAN Turbo

Siemens

ABB

AbengoaSolar

MAN

Ferrostaal

Siemens

Abener

Abengoa Solar

ACS Cobra

Albiasa Solar

Duro Felguera

Flagsol

MAN

Ferrostaal

Orascom

Samca

Sky Fuel

BASF

Bertram

Heatec

Chemicals

Haifa

Heidelberg

Cement

Hydro

Linde

Pilkington

SQM Thyssen

Krupp

3M

Alanod

Cristaleria

Espagnola SA

Flabeg Gmbh

Glasstech Inc

Glaston

Guardian Ind.

HEROGlas

Pilkington

Reec Tech Rioglass Solar

Saint-Gobain

Abengoa

Acciona

Albiasa

Alcoa

Areva (Ausra)

Flagsol

Novatec

Grupo

Sener

Siemens

Sky Fuel Inc

Schott

Solar AG

Siemens

(Solel

Solar Sys)



23/60


InMarch2009,GermanSiemensAGbought a28percentshareofthe

ItaliancompanyArchimedeSolarEnergy,atechnologycompanyofvacuum

receiversforparabolictroughplants.InMay2010,thissharewasincreasedto45percent.

InOctober2009,GermanSiemensAGbought100percentoftheIsraeli

vacuumreceivermanufacturerSolelforS$418million.

InFeb.2010,FrenchArevabought100 percentof the.S.technology

developerAusra.

InMay2010,AlstominvestedS$55millioninBrightsource.

Thischapteridentiesthekeyplayersinthischain,includingtheirfunction

andbackground.Thepositiveattitudeoftheexistingplayerstowardexpanding

theirbusinessactivitiesintheMENAregionisanimportantkeytopromoting

localmanufacturing,achievedthroughthedevelopmentof theirownprojects

intheregion,andtheintentiontoformlocalsubsidiaries,localpartnerships,and

jointventuresforlocalmanufacturing.

Assessment of key parts in the value chain

Thedifferentindustriesrequiredforeachphaseinthevaluechainhavespecic

characteristicsthataredescribedhereindetail.Theseinclude,forexample,busi-

nessmodels,projectexperience,companysize,technologyspecialization,etc.

InTable1.4theindustrialandmarketstructureforthekeycomponentsand

servicesarelisted.Theinternationalindustryisusedhereasanexampleforlocal

industriestoshowhowtheycoulddevelopinthefuture.Afteracloselookat

thekeycomponents,secondaryequipmentforCSPisalsoevaluatedaccordingtoindustrycharacteristics.Resultsareimportantwhenassessinglocalcapabilities

forCSP,becauseinternationalcompanieshaverequiredlong-termexperience

andhaveundertakenlargeinvestmentsinR&Dandtechnologiestoreachmarket

positions.

Materials (raw and semi-nished)

Sincethemostusedrawmaterials(steel,concrete,andcement)areconsumed

fortheconstructionandcivilworksinlargevolumesof50to150tons/MW,it

ismostlylargeplayersinthelocalandnationalconstructionandsteelindustries

whoaremainlyinvolvedinsupplyingtheCSPprojectsandEPCcontractors.

Theassemblyofthecollectorsissuppliedbylargelocalindustrialcompaniesthathaveawiderangeofproductsandservices.CSPisnottheprimarybusiness

concernofthesecompaniesduetothestilllimitedmarketdemand.Thesesup-

plycompaniesareoftenactiveinthebuildingandinfrastructuresectors.They

alsosupplytheautomotiveindustry,whichdemandsalargevolumeofthese

companiesproducts.SomeoftherawmaterialsarespecictotheCSPplants,

whileothermaterialsneededarealsoindemandforconventionalpowerplants.

Thelattercategoryincludesproductssuchas steel,concrete,andcement,and



24/60


Table 1.4 Industry Structure and Context of Component Manufacturing and Serices in

te CSP value Cain

Industry structure Economics and costs

Projectdevelopment

Small group of companies with technologicalknow-how

International actors have fully integratedactivities of concept engineering; often withproject development, engineering, nancing.

Mainly labor-intensive engi-neering activities and activi-ties to obtain permits.

EPC contractors Strong market position for construction, en-ergy, transport and infrastructure projects.

Large infrastructure compa-nies (high turnover)

Parabolicmirrors

Few, large companies, often from the auto-motive sector

Large factory output

Large turnover for a varietyof mirror and glass products

Receivers Two large players Factories also in CSP markets in Spain and US

Large investment in know-how and machines required

Metal supportstructure Steel supply can be provided locally Local and international suppliers can producethe parts

High share of costs for rawmaterial, steel or aluminum

Market structure and trends Key competiveness factor

Projectdevelopment

Strongly depending on growth/expectationsof individual markets

Activities world-wide

Central role for CSP projects Technology know-how Access to nance

EPC contractors Maximum 20 companies Most of the companies active on markets in

Spain and the US

Existing supplier network

Parabolicmirrors

A few companies share market, all have in-creased capacities

High mirror price might decline

Bending glass Manufacturing of long-term

stable mirrors with highreectance

Inclusion of up-stream oatglass process

Receivers Strongly depending on market growth Low competition today; new players about to

enter the market

High-tech component withspecialized production andmanufacturing process

Metal supportstructure

Increase on the international scale expected Subcontractors for assembling and materials

Price competition Mass production/

Automation

Strengths Weaknesses Opportunities Threats

Projectdevelopment

Reference projects Technology

know-how

Dependencyon politicalsupport

Projects inpipeline

Price competi-tion with otherrenewables

EPC contractors Reference projects

Well-trained sta Network of suppliers

High cost Projects inpipeline Achieve highcost reduction

Price competi-tion with otherrenewables

Parabolicmirrors

Strong position offew players

High margins (highcost reductionpotential)

Cost offactory

Continuousdemandrequired

New CSPmarkets

Barriers for mar-ket enrty

Unstable CSPmarket

Flat mirror tech-nology (Fresnel/

Tower)

(continued on next page)



25/60


involvesalargenumberofcompanies.Incontrast,thenumberofcompanieson

theworldmarketthatcansupplyCSPplantsorCSPmanufacturerswithavery

specicrawmaterial(suchasthermaloil)islimited.

Costandlogisticaladvantagesarethemaindriversinselectingasub-contractor

fortheCSPprojectsinSpainorthenitedStates.eryoftenthesupplierssell

theirproductsonaninternationallevel.SpanishCSPplantsarebuiltwithTurkish

steelorIsraeliaifaChemicalssupplysaltforthestoragesystems.

GlasscompanieswhosemanufacturingisnotcenteredaroundCSPmirrorsseethepotentialofagoodbusinessopportunityandselltheirhigh-classmirror

productstothismarket.Therefore,investmentsoftenaremadeinmarketswith

existingproductioncapacitiesandfactories.ProducingCSPmirrorsisconstrained

bytheneedforlow-ironglass(whiteglass,asopposedtoregulargreenglass),

aglassqualityrequiredalmostexclusivelyforthistypeofuse.Solargradeglass

caninprinciplebeproducedatanyoatline,providedthatappropriatelow-iron

sandisusedastherawmaterial.

Power block, steam generator, and heat exchangers

Sincethepowerblockunitusesmanyofthesamecomponentsasconventional

thermalpowerplants,largecompaniesinternationallyactiveinconvertingthermalenergytoelectricityarealsoactiveintheCSPmarket.CompanieslikeGeneral

Electric,Siemens,Alstom,ABB,andMANTurboarethemostimportantplay-

ers for steamturbines,generators,and powercontrol.Thesehigh-technology

companiesalsocoverthetechnicalsideofdistributionandconnectiontothe

grid.Ahighlevelofexpertiseisrequiredforthesecomponentsinordertoreach

continuousoutput,alargenumberofoperatinghoursand,inparticular,high

energy-conversionefciency.Thesteamturbinetechnologyismature,sononew

Table 1.4 Industry Structure and Context of Component Manufacturing and Serices in

te CSP value Cain (continued)

Strengths Weaknesses Opportunities Threats

Receivers High margins (highcost reductionpotential)

Dependencyon CSPmarket

High entrybarrier fornew players(know-how/invest)

High costreduction po-tential throughcompetition

Unstable CSPmarket

Low marketdemand

Strong marketposition offew players;new playersto becomecommercial

Metal supportstructure

Experience New business

opportunities for

structural steel Low entry barriers

High costcompetition

Increase of e-ciency and size

Volatile CSPmarket



26/60


revolutionarytechnologicaladvancementsareexpectedinthishighlycompetitive

andconcentratedmarket,withcompanieslikeSiemens,Alstom,andGEcontrol-

lingthemajorshareoftheglobalmarket.

Storage system

ThecompanySeneriscurrentlythemostexperiencedplayerinthermalstor-

ageforCSPplants.Itisresponsibleforupto12moltensaltsystems(mainly

inSpain)whichareeitherintheoperation,construction,ordesignphase.For

example,thestoragesystemusedinAndasol1consistsoftwotanksof14m

heightand38.5mdiameterwithaconcentrateofnitratemoltensalts(60

percentNaNO3+40percentNO3).Thisengineeringcompanywith5700

employeeshasitsownverystrongR&Ddivision,onwhichSenerspends10

percentofitsrevenues.

Flagsolhaddevelopedthemoltensaltthermalstorageconceptevenbefore

SenerenteredthismarketjointlywithFlagsol.Flagsolwasresponsibleforthe

engineering, procurement, andconstructionof themolten saltstorage of the

Andasol3powerplant(currentlyundercommission).

Ingeneral,themoltensaltthermalstorageisnotatechnologythatcanbe

providedonlybyoneplayer.Thecomponentsusedarestandardcomponentsin

chemicalandenergyplants.Therefore,nomonopoly/oligopolyislikely.owever,

thismightnotbethecasewiththesaltitselfasarawproduct.One7.5hour

storagesystemfora50MWelplantneedsabout3percentoftheannualsaltpro-

ductionofthemainsupplier(SM,Chile).Recentsaltpriceincreasesmightbe

aconsequenceofincreasingdemandfromtheCSPindustry.

Forexample,GermanZblinAGisworkingonastorageconceptwithconcreteasstoragematerial,todayatprototypestatus.

Finance and ownership

ThelargevolumeforthenanceofCSPplants(48Mio.S$/MW)isoften

providedbymanydifferentcompanies,banks,ornancialinstitutions.Onthe

SpanishCSPmarketseveralspecialpurposevehicleshavebeenfoundedbya

projectconsortium.Andasol1wasnancedinthebeginningbythecompanies

SolarMillennium(25percent)andACSCobra(75percent).In2009,afterthe

commissionoftheproject,SolarMillenniumsoldallsharestoACS.Andasol3

holdsashareintheownershipofthespecialpurposevehicleMarquesadoSolar

S.L.ofwhichRWEAG,StadtwerkeMunich,Rheinenergie,MANFerrostaal,andSolarMillenniumalsosharetheownership.

InAlgeria,theISCCplantwasnancedbyaconsortiumoftheengineering

andEPCcontractorAbenerandSonelgaz(NEAL).

Fortheserstprojects,theriskwasconsequentlysharedbetweentheproject

developersandlargerinvestors.Theprojectdeveloperstriedtoissueafundto

increasetheirlimitednancialresourcesinordertoretainthesesharesofap-

proximately25percent.



27/60


Afternishingtheproject,theprojectdevelopmentcompanyveryoftensells

itssharetootherownersfortheoperation.Largedevelopmentaidinstitutions

haveplayedaveryimportantroleinEgyptandMorocco.TheGlobalEnvironmentFacilitytogetherwith its implementingagency theWorldBankhasbeen

stronglyinvolvedinthenancingofCSPplantsbygivinggrantstocoverthe

excesscostsofCSP.

Asinanylargeinvestment,debtnancingisanimportantpillarofnancing

CSPprojects,withashareoftypically7080percentofthetotalprojectvol-

ume.Debtnancinghelpstolowerthecostofcapitalbecauseitischeaper(ap-

proximately57percentp.a.)thaninstitutionalequitynancing(approximately

1215percentp.a.).sually,debtnancingisrealizedbylong-termbankloans

orlong-termbonds.Theeaseordifcultyofrealizingdebtnancingdependson

thebanksriskperceptionofthetechnologies.Today,parabolictroughtechnol-

ogyistheonlytechnologythatisconsideredbankableorproventechnology

becauseofitslong-termperformancetrack-record.

Incomingyears,otherCSP technologieswill achievebankability aswell,

throughproofofperformanceindemonstratorsandincommercialinstallations.

Political institutions

Nationalandinternationalpolicyguidelinesandnewenergylawsonrenewable

energieshavebeenanimportantdriverforCSPprojects,especiallyinSpainand

thenitedStates.WithoutgovernmentalnancialsupportforCSPtechnology,

thedevelopmentofCSPprojectswouldnothavebeeneconomicalandbankable,

duetothecurrenthighercostofCSPtechnologyascomparedtoexistingcon-

ventionalfossilalternativesincompetitiveandliberalizedenergyandelectricitymarkets.PromotionbytheSpanishministry(MinisteriodeIndustria,Turismoy

Comercio)andby.S.federalministriesforenergyhasbeennecessarytopave

thewayforCSPinbothcountries.Inbothcountries,researchactivitiesonall

topicsrelatedtoCSPhavebeenincreased.Theseincludeefciencyincreases,new

storageoptions,higherthermaltemperatures,andnewplantconcepts.

Research & Development

TechnologyresearchinstitutionsinthenitedStates,Germany,andSpainhave

beeninvolvedinmostcommercial technologydevelopments.This technology

transferfrominstitutestotheindustryusuallyhappensthroughthefollowingsteps:

Founding ofnewcompanies from institutes staff (e.g.,NovatecBiosol,

ConcentrixSolarorPSEfromFraunhoferISE;CSPservicesfromtheDLR)

Often,theindustryalsorecruitsemployeesfrominstitutestobuildupa

high-skilledlaborforceofengineersandprojectdevelopers(manyexamples

fromalmostanyinstitutetoalmostanyCSPcompany)

Licensedproductionofcomponents(e.g.,towertechnologybyDLRcom-

mercializedbyraftanlagenMnchen)



28/60


Developmentofmaterials/componentsfortheindustry(e.g.,absorbercoat-

ingofSchottdevelopedbyFraunhoferISE)

Testingof components for the industry(e.g., testingof theEurotroughcollectoronPlataformaSolardeAlmerabyCIEMATandDLR,receiver

testingofNovatecbyFraunhoferISE)

Furthermore,standardizationissuesinCSPtechnologyarecurrentlypushed

forwardonaninternationallevelmainlybyresearchinstitutes(NRELandDLR).

MostactivitiesinCSPstartedfrominitiativesinresearchinstitutes.Allmen-

tionedactivitiescontributedessentiallytothedevelopmentofindustrialprod-

uctsandtheentireCSPsector.Manyleadingengineersanddecisionmakersin

CSPcompanieshaveabackgroundinoneoftheleadingresearchinstitutes.The

marketgrowthincreasedthedemandforwelltrainedstafftoconstruct,operate,

andmaintainaCSPpowerplant.

1.3 Oeriew of Manufacturing Processes for te CSP Components andSystems

Thissectionfocusesontheproductionandassemblystepsofthetechnology.

EveryCSPproductforeachcompanyhasspecicrequirementsduringthemanu-

facturing,production,andassemblyprocesses.Insomecases,thesestepseven

varyfromprojecttoproject;forexample,alargerprojectmightjustifytheuse

ofmass-producedcomponentstobeorderedandproducedonlyinlargevolumes

(especially concerningthe collectorsupportstructure).sing representative

examples,thissectiongivesanoverviewofcomponentproductionforCSPsolar

elds.Asinsection1.1.1,thefocusissetonsolarcollectorsinparabolictroughpowerplants.owever,somegeneralstatementsonthetransferabilityofthepro-

ductionstepstoothertechnologiesarealsoincludedinthedifferentsub-sections.

Themanufacturingprocessesdescribedbelowarestructuredaccordingtothe

followingfourcomponents:

CivilWorksSitePreparationandFoundations(section1.3.1)

ParabolictroughreceiverProductionprocesses(section1.3.2)

BentglassmirrorsProductionprocesses(section1.3.3)

MetalstructureProductionandassembly(section1.3.4)

IflocalmanufacturingistotakeplaceinNorthernAfrica,newproduction

capacitieswillhavetobebuiltupinthesecountries,becausethecurrentcapa-bilitiesarelowornon-existent.Thekeyparameterscomponentcostsandtheir

typicalfactoriesaresummarizedinTable1.5.Ascivilworks,assembly,receivers,

mirrors,andmountingstructurearebyfarthemostimportantpartsoftheplant

intermsof investmentcost, thesemanufacturingprocessesandconstruction

activitiesareassessedanddescribedinparticulardetail.

Storage,whichrepresentsahighshareofthetotalplantcosts(approximately

10percentoftheinvestmentfora7.5hourstorage),includesasignicantcost



29/60


Tale1.5

ImportantP

arametersofManufacturingProcessfor

keyCSPComponentsforEuropeanIndu

stryandEuropeanCSPPlant(continued)

Components

Costpere

ntity

Typicalinvest-

mentinnew

factory

Annualout-

putoftypical

factory

ShareofCSP

pla

ntonan-

nu

aloutput

Jobscreated

One-yearjob=

Fulltimeequiva-

lentforoneyear

One-year

jobs/MW

Shareoflabor

Energy

intensity

Industries

Synergies/

poten

tial

side-markets

CivilWork

250350one-

yearjobsper50

MW

57Jobs/MW

High

Low

Hig

h

Installations

onthesite

100one-year

jobsper50MW

2Jobs/MW

High

Low

Hig

h

EPCEngineers

andProject

Managers

150,000

perEngineer

orProje

ct

Manager

per

year

3040one-year

jobsper50MW

0.60.8Jobs/

MW

High

Low

Hig

h

Assembling

50100one-

yearjobsper50

MW

12Jobs/MW

High

Low

Hig

h

Receiver

8001000

(4mlon

g)

25MioEuro

200MW

1225%

140jobsin

factory

0.30.7Jobs/

MW

Low

Medium

Verylow

Mirror

fat

(Floatglass)

620/

m

26MioEuro

1Miomirrors

200400MW

~20%

250jobsin

factory

0.61.2Jobs/

MW

Medium

High

Hig

h

Mirror

parabolic

2540/m

30MioEuro

1Miomirrors

200400MW

~20%

300jobsin

factory

0.71.5Jobs/

MW

Medium

High

Low(if

glass

productionis

includedthen

high)

(continuedonn

extpage)



30/60


Tale1.5

ImportantP

arametersofManufacturingProcessfor

keyCSPComponentsforEuropeanIndu

stryandEuropeanCSPPlant(continued)

Mounting

structure

4560/m

2.00/kg

2.50/kg

10MioEuro

150200MW

3040%

70jobsin

factory

0.30.5Jobs/

MW

Mediumto

High

High

Medium

HTF

2.703.20/kg

Verylarge

Large

Small

Notidentied

Low

Medium

Low

Connection

piping

Low

High

Medium

Storage

system

$0.65/kg

Salt

50one-year

jobsper50MW

Low

Medium

Low

Electronic

equipment

Notident

ied

Medium

Medium

Small

Notidentied

Medium

Medium

Medium

ReferenceCSP

Plant(50MW,

7,5

hstorage)

7.26M$/

MW

(364M$totally)

(with7

h

storage)

Currentplants

50MWto100

MW

500one-year

jobsper50MW

(onlyonthe

plantsite)

10Jobs/MW

onlyonthe

plantsite

High

Low



31/60


fractionrelatedtoarawmaterialthesaltitselfthathastobeimportedfrom

countrieswithlocalresources.

Thefollowingtableprovidesinformationabouttheimportanceofeachplantcomponentintermsofinvestmentintensityaswellasinitialinvestmentsneeded

forbuildingupproductionfacilitiesfortheindividualcomponents.

1.3.1 civil Wrks Site Preparatin and Fundatins

Themaximalslopeofasiteforaparabolictroughplantis13(NREL,2009).

Withexcavators,thesiteisattenedtomatchtherequirementsofthecollectors.

Thepylonfoundationsofthecollectorsrequireexcavationsofabout2meters

depthonasquareof2.5x2.5meters(Fichtner,2009).Pylonfoundationsare

individuallydesignedforendpylons,drivepylons,middlepylons,andshared

pylons, aswellas inreinforceddesignfor the outerareasof the eld,where

higherwindloadsareexpected,seeFigure1.15.Sometimes,anadditionalwind

barrierhastobeaddedtoavoidlargewindloadsorsandpollutionofthesolar

eld.Additionalcivilworksincludeallconstructionforinfrastructurelikeroads

tothebuildingsiteormachinehouses,assemblinghalls,engineeringofces,and

logisticcentersasafeedstockformaterialandcomponents.Theseworksarebasic

constructionworkandnotCSPspecic;therefore,localcompaniesprovidethis

servicefortheinstallationoftheplant.

Ideallythenatural,non-leveledlandhasaslopeoflessthan1percent;For

PTCandLinearFresnelcollectors3percentisstillfeasible(dependingonground

type).TowerandDishtechnologyarelesssensitivetoslopeandcanacceptup

to5percent(NREL,2009).

1.3.2 Parabli rugh eeiver Prdutin Presses

TheprocessesreferringtothetechnicalcharacteristicsarepresentedinFigure1.16.

andbrieydescribedbelow.AmoredetaileddescriptionisgiveninAnnexA.

Anti-reective coating on borosilicate glass tube The Sol-Gel Process

Tomaximizeopticaltransmissivityofthereceiverglasstube,anantireective

layerisdepositedoneachsurfaceofthetube,seeFigure1.17.

Thecoatingsconsistofavaryingporousstructurethatservesasagradient

ofthereectiveindexfromitslevelinairtoitslevelinborosilicateglass.Due

tothiscontinuousgradient,thereectioncanbereducedtoatheoreticalmini-mum.Tocoatthetube,itisdippedintoanacid-modiedsolutioncontaining

silicondioxideandispulledoutofitataspeedofonecentimeterpersecond

(el,2008).Theresultinglayerhasawidthof110nanometers.Theporous

structureofthelmcanbeachievedbyaddingaporogenmaterialtothe

sol-gelsolution.This compound isremovedduringa heattreatmentafter

thedipping,generatingporesinsidethepolymericsilicalms.Thesol-geldip-

coatingtechnologyisawidelyusedmethodforproducingantireectivelayers



32/60


onlargeareaglassandisalsoappliedtosolarreceivers.Thesol-gelprocessis

applicableonalargescale.

Thetechnicalchallengesaretoachievetemperaturestabilityandresistance

tonaturalimpactslikedirtorrain.

Figure 1.15 cnstrutin Site f rbi Trugh Sr Fie at urymt (Egypt) ith the

Funtins f the Sr Fie

Source: Fichtner, 2009.

Figure 1.16 rbi Trugh Reeier TR 70 f the cmpny Shtt Sr

Collector

Receiver

Reector

Metal Support

Antireective Coating Glass Pipe

Sol-Gel Process

Selective Absorber Coating Steel Pipe

Sputter Technology

Source: Schott, 2009.



33/60


Selective absorber coating The Sputter Process

Tocoatthethinlayersoftheabsorbersystem,preciselayercompositionsandpreciselayerthicknessesarerequiredwithhighhomogeneityonlargesurfaces.

Thisisachievablewiththesputteringtechnology.

Sputteringisbasedonaself-maintainednoblegasdischarge,knownasthe

plasmainanevacuatedchamber.First,thegasisignited(ionized)atlowpres-

sure.Then,forcedbykineticenergysuppliedbyelectricalelds,thegasions

erodesmallmolecularfractionsfromthecoatingmaterial(thetarget)bycolli-

sion(ennedy,2002).Thesefractionsdepositonthesubstrate(theabsorber),

creatingthesputteredlayers.Thedifferentlayersareformedbyusingdifferent

materialsassputtertargetsanddifferentgasesasadditivestothenoblegas

(Zelesnik,2002).Forfurtherdescriptionof theproductiontechniquesplease

refertoAnnexA.

Thistechnology-intensiveproceduralstepisonlyhandledbyveryfewcom-panies,andonlytwoofthem,Siemens(formerlySolel)andSchott,havecom-

mercialexperienceapplyingthesputteringtechnologytovacuumreceiversof

parabolictroughs.

Duetothecomplexityofthesputteringprocess,andduetothedifculty

inconnectingtheabsorbersteeltubetothesurroundingborosilicateglasstube

Figure 1.17 Brsiite Gss Tube withut anti-Reetie cting (eft) n ith anti-

Reetie cting (right)

Source: TU Ilmenau.

Figure 1.18 left: Exempry Sputtere absrber cting (iebrnt, 2009)

Right: Sputtering Mhinery at Frunhfer SE (SE, 2010)

Source: Hildebrandt, 2009, and ISE, 2010.



34/60


(differentthermalconductivityofglassandsteelnormallyleadstoglassbreakage

duringheating),itseemsratherambitiousforMENAcompaniestoenterthe

marketofparabolictroughreceivertechnologyasnewentrantswithnoexperi-enceincoatingprocesses.owever,inthenearfuture,itmightbeinterestingfor

companieslikeSchottandSoleltoopenuplocalproductionfacilitiesassoon

astheMENAmarketsbecomemoreimportantastheyalreadyhaveinSpain

andinthenitedStates.

MostFresnelandTowertechnologiesalsouseselectivelycoatedabsorbertubes

basedonsputtering;theonlydifferenceisthattheyusedifferentmaterials(both

steelandcoatingmaterial)tomatchindividualrequirements(mainlyairstability

andtemperature).Companiesofferingvacuumreceiverscannotautomatically

produceothercoatings(withairstabilityandforothertemperatures)because

thedevelopmentofanapplication-specicsteel-coatingsystemisnecessary.The

machineryandtheproductionprocess,however,isinprinciplethesameforall

theseapplications.

1.3.3 Bent lass irrrs Prdutin Presses

Thereectorisanothercorecomponentofthesolarcollector,asitconcentrates

thesolarirradiationonthereceiver.Theopticalprecisionisgeneratedbyexactly

bentglassmirrorsthatarecoatedwithareectivesilverlayer.Ithasyettobe

proven that collector systemsusing alternativealuminum-or polymer-based

reectivematerialscanachievetherequiredlong-termstabilityaswellasreec-

tivityperformancewhilestillcompetingwiththecostbenchmarkofthethick

glassmirrors.Collectorsbasedonglassmirrorsareexpectedtoremainthemost

importanttechnologylineforquitesometime.Thatiswhythisreportfocuseson

Figure 1.19 rbi Trugh Mirrrs

Collector

Receiver

Reector

Metal Support

Low Iron Float Glass

Float Process

Sag Bending Technology

Reective Silver Layer

Wet Chemical Process

Spraying Technique

Protective Lacquer

In-line

Process

Source: Flabeg Solar 2010.



35/60


theproductionofcommerciallyavailablethickglassmirrors.Furtherinformation

regardingdifferentmirrortypesisgiveninAnnexA.

Production of glass Float processThewholeglassproductionisveryenergydemanding,mainlyduetotheoat

process,andrequireslargeandcapital-intensiveproductionfacilities.owever,

therawmaterialswhichareprimarilywhitesiliconsand,oldwhiteglass,and

sodaashareavailableinhugequantitiesandatlowprice.Theoatprocessis

state-of-the-arttechnologyproducinglargeglasssheetsinhighquantities.The

rawmaterialsarefedintoanindustry-sizemeltingoven,wheretheyareheated

totemperaturesof1600Candtherebyconvertedintomoltenglass(seeSource:

Pilkington,2003).

Themoltenglassispouredcontinuouslyfromthefurnaceontoashallowbath

ofmoltentin.Duetoitsinferiordensity,theglassoatsonthetin,spreadsout,

andformsalevelsurfacebecauseofitssurfacetension,asoildoesonawatersurface.Thethicknessof the glasssheetscanbevariedbythe transportation

speedoftheglassribbonandbytheowspeedofthemoltenglassonthetin

bath,orbystretchingtheglassribbonorcompressingitatitsedges.Figure1.21

andFigure1.22showsketchesoftheglassproductionfacility.

Anastonishing75percentofthetotalenergydemandisduetothemelting

oftherawmaterials.Theoatglassprocessescanhardlyeverbestoppedduring

theentirelifetimeoftheplant,whichisapproximately1015years.Aplant

producesaround6,000kilometersofglassannually,inthicknessesof0.425mm

andinwidthsofupto3meters(Pilkington,2003).

AccordingtoPilkington,over380oatlinesareinoperationworldwide,with

acombinedoutputofabout1,000,000tonsofglassannually.Inotherwords,the

mirrorglassnecessaryfortheAndasol1powerplanttookuptheproductionofaboutoneweekofonelargeoat-glassproductionfacility(seeFigure1.21and1.22).

Mostoftheseoatproductionlines,however,donotproducesolarglass,or

so-calledwhiteglass;instead,theyproducegreenglass,whichcontainsahigher

fractionofirondioxide(andthereforeappearsgreenishattheedges).Formost

applications(e.g.,inhousing),theresultingreductionoftransmittanceofgreen

glassisacceptable,butitisnotsoforsolarapplications,suchasreceiverglass

tubes,parabolicmirrors,andthephotovoltaicindustry.Onlyrecently,anincreasing

Figure 1.20 Gs eter f Ft nt t Met the R Mteris Befre the Ft ress

Source: Pilkington, 2003.



36/60


numberofcompanieshavebeenfocusingonthisnewattractivemarket,mainly

drivenbythedemandofthephotovoltaicindustry.

Consideringthehugeandcomplexmanufacturingline(600mlengthofoat

glassline),thisprocessisveryinvestment-andcapital-intensive.

Bending of glass

Glassbendingisaprocesswhichismainlyusedbytheautomotiveindustry(for

carwindows).Allglassbendingprocessesarethermallydriven.Therearetwo

principleoptionsforbendingglass:thesagbendingprocessandthequenchbend-

ingprocess.Bothprocessesareappliedbydifferentmanufacturersofparabolic

troughmirrors.

Asparabolictroughpowerplantsrequirebentreectors,itisnecessaryto

bendtheglassintoexactshapes.Thebestaccuracyisprovidedbythesag-bending

Figure 1.21 Sketh f Ft ress: after the Meting f the R Mteris, the Mten

Gss is ure ont the liqui Tin t Streth n Frm Ft Surfes

Source: Glasstech, 2010.

Figure 1.22 Sketh f rutin Fiity f in-line Ft ress

Source: AGC, 2010.



37/60


technology(Flabeg,2009).Duringthesagbendingprocess,thetemperatureis

raisedto650C(Glaeser,2001),toreachviscousglasscondition.Thistemperature

canbeprovidedeitherbygasorbyelectricalheaters.Subsequently,theglasssheetisputintoapreciseformingbed,wherethesheetadoptstheparabolicformdue

togravity(seeFigure1.23).

Thequenchbendingprocesscanonlybeappliedtotemperedglass.Glass

temperingisaprocessinwhichtheglassisheatedupto700Candthenshock-

cooled.Thisinducesinnertensionsintheglass,whichincreasesmechanical

stiffnessandisappliedforsecurityreasons(sothatbreakagewillresultinsmall

pieceswithroundedges).

Today,thebendingprocesscanbeperformedbyasinglemachine,allowing

forhighlyautomatedproduction.Eventheintegrationintoanotherproduction

lineispossible,duetothemodularityofthebendingprocess.

Turning a glass sheet into a mirror Wet chemical spraying

Thisprocessisappliedtocoatthebentglasssheetswithreectivesilverand

necessaryprotectivelayers.

First,theparabolicbentglasssheetshavetobecleanedbyapolishingand

washingmachineusingonlydematerializedwater(Glaeser,2001)toguarantee

aperfectlycleanglasssurface(innanoscale).Afterthat,thesheetshavetobe

silvered,whichisachievedthroughasprayingprocess.

Thesolutionscontainingthesilvernitrateandthereducingagents(whichare

prepared,stored,andappliedseparately)arepumpedtosprayinggunstospread

themixtureontothepanesurface(Glaeser,2001).Thelayerisgeneratedim-

mediately,assoonastheliquidsmixandhittheglasssurface.Itisveryimportanttoavoidreducingthesilvernitratesolutionwiththereducingagentsbeforeit

proceedsfromthegunstotheatglasspane;otherwisethemirrorsurfacemay

containcorns.

Thenextstepafterthesilver

layergenerationistodeposita

protectivecopperlayeronthe

reectivecoatinginaseparate

chamber.After that,the sys-

temisdriedbyradiantheaters

andnallycoatedwithspecial

lacquerstobeabletoresistthe

impactsofnatureindesert-likeareasduringthewholelife-time

oftheCSPpowerplant.The

entire coating of silver mir-

rorsiscarriedoutasanin-line

process(Glaeser,2001).In-line

silveringplantshavealength

of approximately200m.To

Figure 1.23 reise Rint eter fr Sg

Bening

Source: Glaston, 2010.



38/60


operateamodernplant,a largeamountofdemineralizedwater anda steadyenergysupplyisnecessary.

SolarTowersandLinearFresnelcollectorsuseatglassmirrors(see Source:

SaintGobain,2010).Thismeansthatthebendingprocess(andinsomecases

alsotheglasstempering)2canbeomitted.Thepadsforthexationofthemir-

rorstothetroughmirrorsupportstructurecanalsobeomittedforatmirrors.

Companiesofferingbentparabolicmirrorstypicallyalsoofferatglassmirrors.

Thereverseisnottrue.Acompanywhichisabletoproduceonlyatglass

mirrorshastoinvestsignicanteffortstolearntheprocessesforbendingand

coatingtheglass.

1.3.4 etal Struture Prdutin and ssemblyAfterthereceiverandthemirrors,themetalsupportstructureisthethirdcorecomponentofthesolarcollector.Thereisalargevarietyofcollectorstructuresonthemarkettoday;someexamplesofdifferentstructuretypesarecompiledinTableA.1.AscompetitionamongtheCSPcollectorprovidersincreasesandthemarketconditionstoughen,cost-efcientconceptsbasedonmassproduc-tionandstandardizedcomponentsincreasetheirmarketshare.Thatiswhytheinvolvedengineeringcompaniesdevelopconceptsbasedonfewerdifferentpartsandfasterproductionassemblies.Today,thereisstillhugecost-savingpotentialregardingthiscomponent,asthewholeassemblyandconstructionprocessisnotnearlyasdevelopedasmodernautomotiveequivalents.

Themountingproceduresofthedifferentcollectorsystemsvary,anddetails

ofthestructureandtheassemblyareusuallyproprietaryknow-howofthecompanies.Forexample,theproductionandtheassemblyofthesteelstructure

2Thetemperingoftheglassresultsinmechanicallymorestableglasssheetswhich,ontheotherhand,breakintosmallglasspieces,incaseofbreakage(securityglass).Bothtemperedandnon-temperedglassisprovidedbytheCSPmirrorindustryandisusedinbothtroughandFresneltechnologies.(E.g.Flabegusesnon-temperedglass.)

Figure 1.24 Siering f Gss Mirrrs n appitin f rtetie lyers

Source: Glaeser, 2001.



39/60


oftheSpanishcompanySener

(SenerTrough),using stamped

cantileverarms(Sener,2007),aredescribedhere,accordingtotheir

chronologicalsteps:

Galvanizingprocess

Stampingprocess(cantile-

verArms)

Weldingprocess

igassembly

Galvanizing process

Thesteelstructureisprotected

againstcorrosiveinuencessuch

as humidity fromwet cooling,

nightlycondensation,andhighair

salinityincoastalareas.Toprovide

protectionagainstthesethreats,

differentwell-knownapplications

are available.All CSPcollector

typesusingsteelstructuresneed

toapplysuchaprotectionagainst

corrosion.

otdipgalvanization(amet-allurgicalprocess)isthemost

common protection method,

coatingsteelwithathinzinc

layerduringadipcoatingprocess.

Duringthecoating,themetal

isputintoaconductiveliquid,andthenanelectricalcurrentisconnected,see

Source:Sener,2007

iaanelectriceld,thezincmoleculesaretransportedtothemetaland

formaprotectivelayeronit.Thezinccoatingpreventscorrosionofthemetal

byformingaphysicalbarrier.Whenexposedtotheatmosphere,zincreactswith

oxygentoformzincoxide,whichfurtherreactswithwatermoleculesintheair

toformzinchydroxide,andlaterwithcarbondioxidetoformzinccarbonate.Thisthinlayerisimpermeable,tenacious,andinsoluble,protectingthedeeper

layersfromcorrosion.

Thishotdipgalvanizationresultsinaverythincoatingthatpreventscorro-

sionofthemetalsupport.Theadvantageofthisprocessisitslowcostandease

ofapplicationcomparedtootherprotectivecoatingslikelacquers.

Figure 1.25 cnstrutin f Sr Gss Mirrrs

Source: Saint Gobain, 2010.



40/60


Stamping: Cantilever arms

Stampingtechniquesallowma

ESMAP MENA Local Manufacturing Chapter 1

Documents

Transcript of ESMAP MENA Local Manufacturing Chapter 1