solar handbook

1Handbook for Solar Photovoltaic (PV) Systems

Contents

1 Solar Photovoltaic (PV) Systems An Overview 4 1.1 Introduction 4 1.2 Types of Solar PV System 5 1.3 Solar PV Technology 6 CrystallineSiliconandThinFilmTechnologies 8 ConversionEfficiency 8 EffectsofTemperature 9 1.4 Technical Information 10

2 Solar PV Systems on a Building 12 2.1 Introduction 12 2.2 Installation Angle 12 2.3 AvoidShadingPVModules 13 2.4 AestheticandCreativeApproachesinMountingPVModules 14 2.5 SolarPVOutputProfile 14 2.6 Solar PV Yield 15 2.7 CostofaSolarPVSystem 15

3 Appointing a Solar PV System Contractor 16 3.1 Introduction 16 3.2 Getting Started 17 GetanExperiencedandLicensedContractor 17 ChoosingBetweenBids 17 SolarPVSystemWarranty 17 RegularMaintenance 19 OtherRelevantMatters 19

4 Solar PV System Installation Requirements 20 4.1 ElectricalInstallationLicence 20 4.2 ElectricalSafetyStandardsandRequirements 20 4.3 ApplicationofElectricalInstallationLicence 21 4.4 ConservationandDevelopmentControlRequirements 21 4.5 GuidelinesonConservationandDevelopmentControl 21 4.6 StructuralSafetyandLightningProtection 22 StructuralSafety 22 LightningProtection 22 4.7 ConnectiontothePowerGrid 22 4.8 GetConnectedtothePowerGrid 23 4.9 SaleofSolarPVElectricity 23 4.10 DesignandInstallationChecklist 27

5 Operations and Maintenance 28 5.1 OperationsofSolarPVSystems 28 5.2 RecommendedPreventiveMaintenanceWorks 29

1Appendices

APPendIx A exAMPleS Of SOlAR PV SySteM On BuIldIngS In SIngAPORe A.1 ZEROENERGYBUILDING@BCAACADEMY 32

A.2 POHERNSHIH(TEMPLEOFTHANKSGIVING) 34

A.3 313SOMERSETCENTRAL 36

A.4 SENTOSACOVE 38

A.5 MARINABARRAGE 40

A.6 LONZABIOLOGICS 42 A.7 ZEROENERGYHOUSE 44

A.8 TAMPINESGRANDE 46

A.9 HDBAPARTMENTBLOCKSATSERANGOONNORTHPRECINCT 48 A.10 HDBAPARTMENTBLOCKSATWELLINGTONCIRCLEPRECINCT 50

APPendIx B B.1 ENGAGINGALICENSEDELECTRICALWORKER 52

APPendIx C C.1 CONTACTINFORMATION 54

APPendIx d InCentIVeS fOR SOlAR PV SySteM D.1 SOLARCAPABILITYSCHEME(SCS) 55

D.2 MARKETDEVELOPMENTFUND(MDF) 56

D.3 GREENMARKSCHEME 57

D.4 GREENMARKGROSSFLOORAREA(GM-GFA)INCENTIVESCHEME 58

D.5 $100MILLIONGREENMARKINCENTIVESCHEME 59 FORExISTINGBUILDINGS(GMIS-EB)

D.6 ENHANCED$20MILLIONGREENMARKINCENTIVESCHEMEFOR 60 NEWBUILDINGS(GMIS-NB)

2Cognizantofthegrowingpopularityofsolarphotovoltaic(PV) installationsamongstresidentialdwellersaswellasbuildingdevelopers,and thecorrespondingdemand foracomprehensivesetoftechnicalandregulatoryinformation,theEnergyMarketAuthority(EMA)andtheBuildingConstructionAuthority(BCA)gottogetherearlierthisyeartoworkonintegratingtheirrespectivesolarmanuals intoanall-in-onereferenceguidefor thosewhoarekeenon installingsolarPVsystems in Singapore.

The outcome of this joint project,which also saw the involvement of industry partners andstakeholderssuchasPhoenixSolarPteLtd,GrenzonePteLtd,SolarEnergyResearchInstituteofSingapore(SERIS)andSingaporePolytechnic, isthisHandbookforSolarPhotovoltaic(PV)Systems. Through this integrated and revised handbook, we hope to be able to provide acomprehensiveguidetotherelevantparties,includingowners,developers,engineers,architects,Licensed ElectricalWorkers and electricians on the key issues, requirements and processespertaining to the installation of solar PV systems.

Aswiththepreviouseditionofthehandbooks,thissinglevolumecoversandprovidesinformationonlicensing,marketandtechnicalrequirements,andbuildingandstructuralissuesthatarerelatedtotheimplementationofsolarPVsystemsinabuildingenvironment.Inaddition,itprovidesnewinformationontheinstallationrequirementsforsolarPVsystems,operationsandrecommendedpreventivemaintenanceworks,andvariousincentivestopromotesolarPVsystemsinSingapore.Wehavealsorefreshedthepresentationofthehandbooktomakeitmoreaccessibleandreader-friendly,aswellastoincorporateexamplesofcompletedsolarPVinstallationsinSingapore.

Wehopeyouwillfindthistobeausefulguide.

david tan Ang Kian SengDeputy Chief Executive DirectorEnergyPlanningandDevelopmentDivision CentreofSustainableBuilding&ConstructionEnergyMarketAuthority BuildingandConstructionAuthority

foreword

2

33

Acknowledgements

Wewouldliketothankthefollowingorganisationsfortheirsupportandcontributionsinthedevelopmentofthishandbook:

1) GrenzonePteLtd

2) PhoenixSolarPteLtd

3) SingaporePolytechnic

4) SolarEnergyResearchInstituteofSingapore(SERIS)

5) SPPowerGrid

6) UrbanRedevelopmentAuthority

41Solar Photovoltaic (PV) Systems An Overview figure 1. the difference between solar thermal and solar PV systems

1.1 Introduction

Thesundeliversitsenergytousintwomainforms:heatandlight.Therearetwomaintypesofsolarpowersystems,namely,solarthermalsystemsthattrapheattowarmupwater,andsolarPVsystemsthatconvertsunlightdirectly intoelectricityasshowninFigure1.

When thePVmodules are exposed to sunlight, they generate direct current (DC)electricity.AninverterthenconvertstheDCintoalternatingcurrent(AC)electricity,sothatitcanfeedintooneofthebuildingsACdistributionboards(ACDB)withoutaffectingthequalityofpowersupply.

5Chapter 1SOlAR PhOtOVOltAIC (PV) SySteMS An OVeRVIew

figure 2. grid-connected solar PV system configuration

1.2 Types of Solar PV System

SolarPVsystemscanbeclassifiedbasedontheend-useapplicationofthetechnology.TherearetwomaintypesofsolarPVsystems:grid-connected(orgrid-tied)andoff-grid(orstandalone)solarPVsystems.

Grid-connectedsolarPVsystems

ThemainapplicationofsolarPV inSingapore isgrid-connected,asSingaporesmainislandiswellcoveredbythenationalpowergrid.MostsolarPVsystemsareinstalledonbuildingsormountedonthegroundiflandisnotaconstraint.Forbuildings,theyareeithermountedontherooforintegratedintothebuilding.ThelatterisalsoknownasBuildingIntegratedPhotovoltaics(BIPV).WithBIPV,thePVmoduleusuallydisplacesanotherbuildingcomponent,e.g.windowglassorroof/wallcladding,therebyservingadual purpose and offsetting some costs.

Theconfigurationofagrid-connectedsolarPVsystemisshowninFigure2.

Abuildinghastwoparallelpowersupplies,onefromthesolarPVsystemandtheotherfromthepowergrid.ThecombinedpowersupplyfeedsalltheloadsconnectedtothemainACDB.

TheratioofsolarPVsupplytopowergridsupplyvaries,dependingonthesizeofthesolarPVsystem.WheneverthesolarPVsupplyexceedsthebuildingsdemand,excesselectricitywill be exported into the grid.When there is no sunlight to generate PVelectricityatnight,thepowergridwillsupplyallofthebuildingsdemand.


figure 3. Off-grid solar PV system configuration

Agrid-connectedsystemcanbeaneffectivewaytoreduceyourdependenceonutilitypower,increaserenewableenergyproduction,andimprovetheenvironment.

Off-gridsolarPVsystems

Off-gridsolarPVsystemsareapplicableforareaswithoutpowergrid.Currently,suchsolarPVsystemsareusuallyinstalledatisolatedsiteswherethepowergridisfaraway,suchasruralareasoroff-shoreislands.Buttheymayalsobeinstalledwithinthecityinsituationswhereitisinconvenientortoocostlytotapelectricityfromthepowergrid.Forexample,inSingapore,severalURAparkingsignlightsarepoweredbyoff-gridsolarPV systems.

Anoff-gridsolarPVsystemneedsdeepcyclerechargeablebatteriessuchaslead-acid,nickel-cadmium or lithium-ion batteries to store electricity for use under conditionswherethereislittleornooutputfromthesolarPVsystem,suchasduringthenight,asshowninFigure3below.

1.3 Solar PV Technology

This section gives a brief description of the solar PV technology and the commontechnical terms used.

AsolarPVsystemispoweredbymanycrystallineorthinfilmPVmodules.IndividualPV cells are interconnected to form a PV module. This takes the form of a panel for easy installation.


Mono-Crystalline Silicon PV Cell Poly-Crystalline Silicon PV Cell

figure 5. PV technology family tree

PV Cell Types

Poly-crystalline

Mono-crystalline

Amorphous-Si (a-Si)

Tandema-Si/microcrystalline

CIGS(Copper Indium Gallium

Selenide)

CdTe(Cadmium Telluride)

Dye-sensitised (TiO2)

Commerciallyavailable product,

suitable for Singapore

R&D or pilot stage, orunsuitable for

Singapore

Special

Compound semiconductoreg GaAs-based

Crystalline Silicon(wafer based) Thin Film

PVcellsaremadeoflight-sensitivesemiconductormaterialsthatusephotonstodislodgeelectronstodriveanelectriccurrent.TherearetwobroadcategoriesoftechnologyusedforPVcells,namely,crystallinesilicon,asshown inFigure4whichaccounts for themajorityofPVcellproduction;andthinfilm,whichisnewerandgrowinginpopularity.ThefamilytreeinFigure5givesanoverviewofthesetechnologiesavailabletodayandFigure6illustratessomeofthesetechnologies.

figure 4. Mono-and Poly-Crystalline Silicon PV Cell


CIgS thin filmMono-crystalline silicon

Poly-crystalline silicon

flexible amorphous thin film

figure 6. Common PV module technologies

CrystallineSiliconandThinFilmTechnologies

Crystallinecells aremade fromultra-puresilicon rawmaterial suchas thoseused insemiconductorchips.Theyusesiliconwafersthataretypically150-200microns(onefifthofamillimetre)thick.

Thin film is made by depositing layers of semiconductor material barely 0.3 to 2micrometres thick onto glass or stainless steel substrates. As the semiconductor layers aresothin,thecostsofrawmaterialaremuchlowerthanthecapitalequipmentandprocessing costs.

ConversionEfficiency

technology Module efficiency Mono-crystallineSilicon 12.5-15% Poly-crystallineSilicon 11-14% CopperIndiumGalliumSelenide(CIGS) 10-13% CadmiumTelluride(CdTe) 9-12% AmorphousSilicon(a-Si) 5-7%

table 1. Conversion efficiencies of various PV module technologies

Apart from aesthetic differences, the most obvious difference amongst PV celltechnologiesisinitsconversionefficiency,assummarisedinTable1.

Forexample,athinfilmamorphoussiliconPVarraywillneedclosetotwicethespaceofacrystallinesiliconPVarraybecause itsmoduleefficiency ishalved,forthesamenominalcapacityunderStandardTestConditions1(STC)rating.

1StandardTestConditionsrefertothefollowingtestingconditions:1,000W/m2 of sunlight250CcelltemperatureSpectrumatairmassof1.5


ForcrystallinesiliconPVmodules,themoduleefficiencyislowercomparedtothesumofthecomponentcellefficiencyduetothepresenceofgapsbetweenthecellsandtheborderaroundthecircuit i.e.,wastedspacethatdoesnotgenerateanypowerhencelowertotalefficiency.

EffectsofTemperature

AnotherimportantdifferentiatorinsolarPVperformance,especiallyinhotclimates,isthetemperaturecoefficientofpower.PVcellperformancedeclinesascelltemperaturerises.

Forexample, inbright sunlight, cell temperatures inSingapore can reachover70C,whereasPVmodulesareratedatacelltemperatureof25C.Thelossinpoweroutputat70Cisthereforemeasuredas(70-25)xtemperaturecoefficient.

Mostthinfilmtechnologieshavealowernegativetemperaturecoefficientcomparedtocrystallinetechnologies.Inotherwords,theytendtoloselessoftheirratedcapacityastemperaturerises.Hence,underSingaporesclimaticcondition,thinfilmtechnologieswillgenerate5-10%moreelectricityperyear.

APVmoduledatasheetshouldspecifythetemperaturecoefficient.SeeTable2andchartinFigure7.

technology temperature Coefficient [%/C] Crystallinesilicon -0.4to-0.5 CIGS -0.32to-0.36 CdTe -0.25 a-Si -0.21

table 2. temperature coefficient of various PV cell technologes

mod

uleou

tputre

lativetoSTC

figure 7. the effects of a negative temperature coefficient of power on PV module performance

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Chapter 1SOlAR PhOtOVOltAIC (PV) SySteMS An OVeRVIew

1.4 Technical Information

Single-core, double isolated sheathed cables that can withstand the environmentalconditions,andminimisetheriskofearthfaultsandshortcircuitsareusedtointerconnectthePVstringsandarrays.ThecableconnectionsareprotectedinenclosuresknownasjunctionboxthatprovidesthenecessaryconnectorsasshowninFigure10.

figure 8. PV String figure 9. PV Array

figure 10. Junction Box

ElectricityproducedbythesolarPVinstallationisintheformofDC.TheoutputofthePVinstallationisconnectedthroughtheDCmaincablestotheDCterminalsofthePVinverterwhereelectricityisconvertedfromDCintoAC.

After conversion, theAC current of thePV inverter is connected throughPV supplycabletothebuildingselectricalinstallation(ACdistributionboard).

Figure 11 shows a typical PV inverter connected to the electrical installation of abuilding.NotethattheactualconfigurationofthePVinvertermayvaryacrossdifferentsystems.

ThePVmodulesarenextconnectedinseriesintoaPVstringasshowninFigure8. APVarrayasshowninFigure9isformedbytheparallelaggregationofPVstrings.

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Chapter 1SOlAR PhOtOVOltAIC (PV) SySteMS An OVeRVIew

Justlikeanyelectricalinstallationinabuilding,earthingisanimportantsafetyrequirementfor solar PV system. Arrangement must be made for proper connection of the solar PV system to the consumers electrical installation earthing system.

In locations susceptible to lightning strikes, a lightning protection system must beprovided,andalltheexposedmetallicstructuresofthesolarPVsystemmustbeboundto the lightning earthing system.

It is the responsibility of the consumers to have their solar PV systemsmaintainedregularly to ensure safe operation of their solar PV systems and electrical installations. SeeFigure12foradiagramshowingthesolarPVsystemformingpartofaconsumerselectrical installation.

figure 11. typical PV inverter connected to a buildings electrical installation

figure 12. Solar PV system forming part of a consumers electrical installation

dC Side AC Side

PVInverter

PV dC Main Cable

PV SupplyCable

AC distributionBoard

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2Solar PV Systems on a Building2.1 Introduction

TherearemanyexamplesoverseaswherePVmodulesaremountedontheroofandintegratedintobuildingfaades.TheyworkparticularlywellinEuropeandNorthAmerica,assouth-facingfaadesintheseregionsarewellexposedtothesun.

InSingapore,wehavetoconsiderthatthesunpassesalmostdirectlyoverhead.ThisisbecausewearelocatedneartheEquator,andthepathofthesunfollowstheEquator,withseasonalvariationsofupto23.5o to the north or south. Therefore there are optimal positionstolocatethePVmodulesthathavetobetakenintoconsideration.RefertoAppendixAforexamplesofsolarPVsystemsonbuildingsinSingapore.

2.2 Installation Angle

To maximise electricity production for use in Singapore, the best location for thePVmodules tobe installed is righton topofabuilding, facing thesky.ThepossibleinstallationoptionsareshowninFigure13.

figure 13. where to install PV modules on a building in Singapore

13

figure 14. PV module frames trap dirt as water evaporates from aflat-mounted PV module

Vertical faades and steeply sloped roofs tend to suffer a big loss in the ability to generate electricityinexchangeforhigherpublicvisibility.

WiththePVmodulesfacingthesky,itispossibletoimprovetheyieldbyinstallingPVmoduleson trackers to follow thesun fromeast towestduring theday (single-axistrackers),andfromnorthtosouthduringseasonalchanges(dual-axistrackers).

However, trackerscanonly improvesystemperformanceunderdirectsunshine,andtheygivenoadvantageindiffusedsunlightconditions,suchasoncloudyorhazydays.

Thedownsideofhavingflat-mountedPVmodulesisthattheytendtogetdirtyfromrainwateranddust.SeeFigure14.ItisthereforebettertomountthePVmodulesatanincline(10-15oforframedmodules,oraslittleas3-5oforunframedmodules),toallowrainwatertoproperlydrainoff

2.3 Avoid Shading PV Modules

PV modules should be free from shade. Shading of any single cell of a crystalline silicon PVmodulewilldrasticallyreducetheoutputoftheentirePVmodule.

Thin filmPVmodules aremore tolerant to partial shading than crystalline siliconPVmodules.Typicalculpritsincludeshadowscastbytalltreesandneighbouringbuildings.

Chapter 2SOlAR PV SySteMS On A BuIldIng

14


2.5 Solar PV Output Profile

SolarPVonlyproduceselectricitywhensunlightisavailable.TheoutputofasolarPVsystemvarieswithitsratedoutput,temperature,weatherconditions,andtimeoftheday.ThepoweroutputprofileofthePVinstallationasshowninFigure17,ataselectedtestsiteinSingaporecollectedoveraperiodfrom2002-2004,intermsofitscapacityfactor2,showsahighvariationofsolarPVoutput.

figure 15. BIPV modules integrated into a faade

figure 16. BIPV modules integrated into a skylight canopy

2.4 Aesthetic and Creative Approaches in Mounting PV Modules

Besides mounting PV modules on the rooftop, customised PV modules can beintegratedintothebuildingfaadeinacreative,aestheticallypleasingmanner.Theycanbemountedonanypartoftherooftoporexternalwallsthatiswellexposedtosunlighte.g.skylights,cladding,windows,andexternalshadingdevices.

Theycanalsobeintegratedintoexternalstructuressuchasfaadesandcanopies,asshowninFigure15andFigure16,respectively.

[2] PV Output capacity factor = Ratio of the actual output of the PV installation at time (t) over its output if it had operated at full rated output.

15

2.6 Solar PV Yield

The amount of electricity you are able to generate from a solar PV system depends not onlyontheavailabilityofsunshinebutalsoonthetechnologyyouchoosetoinstall.Forexample,atypical10-kWrooftopsolarPVsysteminSingaporewouldproduceabout11,000to12,500kWhannuallyusingcrystallinePVmodules,and12,000to14,500kWhannuallywithamorphoussiliconthinfilmPVmodules.

2.7 Cost of a Solar PV System

ThecostofyoursolarPVsystemwilldependonmanyfactors:systemconfiguration,equipmentoptions,labourcostandfinancingcost.Pricesalsovarydependingonfactorssuchaswhetherornotyourhomeisnew,andwhetherthePVmodulesareintegratedinto the rooformountedon the roof.Thecost alsodependson thesystemsizeorrating,andtheamountofelectricityitproduces.

Generally,solarPVsystemsentailhighcapitalcosts.Withsolarpower,youcansaveonthepurchaseofelectricityfromthegrid.Butevenwiththesesavings,itwilltakealongtimetorecoverthecapitalcostofthesolarPVinstallation.TheoperatingcostsforsolarPV installationsarenegligible,but theannualmaintenancecostbeyondthewarrantyperiodmayamountto0.5%to1%ofthecapitalcostoftheinstallation.

Thereforeonanoverallbasis,solarPV-derivedelectricityisstillmuchmoreexpensivethanthatfromthepowergrid.However,thecostofsolarPVhashistoricallybeenfallingbyabout4%ayear,andifthiscontinues,solarPVmaybecompetitivewithinthenext10years.ForincentivesonsolarPVsystem,pleaserefertoAppendixD.

figure 17. Varying daily power output profile of PV installation at a selected test site in Singapore


PV

ou

tpu

t ca

pac

ity

fact

or

16

3Appointing a Solar PV System Contractor3.1 Introduction

YouwillneedtoselectacontractortoinstallyoursolarPVsystem.Ifinterested,youmaycheckwiththefollowingorganisationsforsomesolarPVsystemdesignersandcontractors:

TheListofSolarPVSystemcompanies inSingapore,available fromSustainableEnergyAssociationofSingapore,bycalling63388578orbyvisiting

http://www.seas.org.sg/about-seas/our-committees/cleanenergy/54

TheSingaporeSustainableDevelopment IndustryDirectory 2008/2009, availablefromtheSingaporeBusinessFederation,bycalling68276838orbyvisiting

http://www.sbf.org.sg/public/publications/industrydirectory.jsp

YourcontractorwillappointaLicensedElectricalWorker(LEW)whowillberesponsibleforthedesign,installation,testing,commissioning,andmaintenanceofyoursolarPVsystem.

Inthecaseofnon-residentialelectricalinstallationsthatrequireanelectricalinstallationlicence,theappointedLEWwhosupervisestheelectricalwork(DesignLEW)maynotbetheonewhotakeschargeofyourelectricalinstallation(InstallationLEW).TheDesignLEWwillthenhavetoworkwiththeInstallationLEWtoworkoutthetechnicalissues.

PleaserefertoAppendixBfordetailsonhowyoucanengageanLEWandthenecessaryconsultation process.

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Chapter 3APPOIntIng A SOlAR PV SySteM COntRACtOR

3.2 Getting Started

First, compile a list of potential solar PV system contractors. Next, contact thecontractorstofindouttheproductsandservicestheyoffer.Thefollowingpointersmaygiveconsumersagoodsenseofthecontractorscapabilities:

Getanexperiencedandlicensedcontractor

Experienceininstallinggrid-connectedsolarPVsystemsisinvaluable,becausesomeelements of the installation process, particularly interconnection with the grid, areuniquetothesesystems.Acontractorwithyearsofexperiencewillalsodemonstrateanabilitytoworkwithconsumers,andpricetheirproductsandservicescompetitively.

ItisalsoimportanttogetacontractorwhoisanLEW.

Choosingbetweenbids

IfthereareseveralbidsfortheinstallationofasolarPVsystem(itisgenerallyagoodpractice to obtainmultiple bids), consumers should take steps to ensure that all ofthebidsreceivedaremadeonthesamebasis.ComparingabidforasolarPVsystemmounted on the ground against another bid for a rooftop system is like comparing apples to oranges.

Bids should clearly state themaximum generating capacity of the solar PV system[measured inwattspeak (Wp)or kilowattspeak (kWp)]. If possible, thebids shouldspecify thesystemcapacity inACwatts,orspecify theoutputof thesystemat theinverter.

Bids should also include the total cost of getting the solar PV systemcomponents,includinghardware,software,supportingstructure,meter,installation,connectiontothegrid(ifapplicable),permitting,goodsandservicestax,warranty,andfuturemaintenancecost(ifapplicable).

SolarPVsystemwarranty

AsolarPVsystemisaninvestmentthatshouldlastalongtime,typicallytwotothreedecadesforgrid-connectedapplications.TheindustrystandardforaPVmodulewarrantyis20-25yearsonthepoweroutput.

TherearetwomaincomponentstoaPVmodulewarranty:

Aworkmanshipwarrantythatofferstorepair,replaceorrefundthepurchasein case of defects. The period varies from one to as long as ten years,dependingonthemanufacturer.Twotofiveyearsistypical;and

18

AlimitedpoweroutputwarrantythatoffersavarietyofremediesincasethePVmodulesoutputunderSTCdropsbelowcertainlevel.Mostmanufacturerswarrantatleast90%oftheminimumratedoutputfor10years,and80%oftheminimumratedoutputfor20-25years.Takenotethattheminimumratedoutputisusuallydefinedas95%oftheratedoutputtoallowformanufacturingandmeasurementtolerances.SeeFigure18fordetails.


Takenotethatunderthelimitedpowerwarranty,manufacturersseldomoffertoreplacethePVmoduleitself.Rather,attheirsolediscretion,theymayofferto:

RepairthedefectivePVmodules; SupplyenoughnewPVmodules to replace the lostpoweroutput in aPV

array.Forexample,ifyour20kWPVarrayonlyproduces16.1kWunderSTC,sixyearsafterinstallation,themanufacturermayopttosupplyyouwith1kWof PV modules to make up for the shortfall; or

Refundyouforthelostpoweroutput,afterdeductionaccordingtothenumber

ofyearsinuse.Fora25-yearwarranty,theannualdeductionisnormally4%.Forexample,ifyoufindthatyour20kWPVarrayonlyproduces16.1kWunderSTC,sixyearsafterinstallation,themanufacturermayopttoreimburseyourpurchasepriceminus24%(6yearsx4%).

Inallcases,themanufacturerdoesnotcoveryourcostsofdismounting,transporting,andreinstallingthePVmodules.Thewarrantyalsoexcludesproblemsresultingfromimproper installations; repairs, changes or dismounting by unqualified personnel;accidental breakage or abuse; lightning strikes and other acts of God.

figure 18. understanding a manufacturers limited power warranty

19


Significantly,mostmanufacturersspecifythatthePVmoduleoutputwillbedeterminedbytheflashtestersintheirownpremises,ratherthanbyathirdparty.

The solar PV system contractor should assist in determiningwhether a PVmoduledefectiscoveredbywarranty,andshouldhandlethesituationwiththemanufacturer.

Regularmaintenance

Duringthedefectliabilityperiod(usuallyfor12monthsafterinstallation),solarPVsystemcontractors usually use remote monitoring data to prepare monthly performance reports of the installed solar PV system. They should come on site to rectify any problems flaggedbytheremotemonitoringservice.

Otherrelevantmatters

AnothermattertobeawareofisthatPVmodulemanufacturersareconstantlyupgradingtheirproducts,andadaptingnewsizesanddimensionstosuitmarket requirements.This means that you may no longer be able to buy an identical PV module to replace adefectiveoneinyourPVarrayafewyearsafterinstallation.NewerPVmodulesarelikelytobemoreefficientorhavedifferentphysicaldimensions,andmaynolongerfitexactlyintothegapleftbytheoldPVmodule.

Thisdoesnotmattermuchonalarge,ground-mountedsolarPVpowerplant,becausethenewmodulescanformanewrow.Butonabuilding-mountedsolarPVsystemitmayspoiltheaesthetics,andmaycauseproblemstotheelectricalconfiguration.

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4Solar PV System Installation Requirements4.1 Electrical Installation Licence

An electrical installation refers to any electrical wiring, fitting or apparatus used fortheconveyanceandcontrolofelectricityinanypremises.AsolarPVsysteminstalledwithin suchpremises formspart of the consumers electrical installation and shouldcomplywiththerequirementsstipulatedintheElectricityAct(Cap.89A),theElectricity(ElectricalInstallations)RegulationsandtheSingaporeStandardCP5CodeofPracticeforElectricalInstallations.

Under the Electricity Act, the Energy Market Authority (EMA) licenses all non-residentialelectricalinstallations,withdemandexceeding45kilovoltampereorkVA.Forresidentialelectricalinstallationsandnon-residentialelectricalinstallationswithdemandbelowthethreshold45kVA,noelectricalinstallationlicenceisrequired.

ThelicencerequirestheowneroftheelectricalinstallationtoengageanLEWtotakechargeoftheelectricalinstallationandcomplywiththerelevantsafetystandardsandrequirements.YourappointedLEWshallconsultSPPowerGridLtdontheir technicalrequirementsandprocedures, ifyouwishtooperateyoursolarPVsysteminparallelwiththepowergrid.Theobjectiveistoensureallelectricalinstallations,includingsolarPVsystems,aresafetouse.

4.2 Electrical Safety Standards and Requirements

Agrid-connectedsolarPVsystemoperatesinparallelwiththepowergridsupply.Thepowergridsupplyisconsideredthesource,andtheelectricalinstallationwiththesolarPV system connected is considered as the load.

ThetechnicalrequirementforinstallationofasolarPVsystemisgiveninSection612oftheSingaporeStandardCP5.

ThereareinternationalproductstandardsonPVmodulesandelectricalcomponents.Forexample,PVmodulesshouldcomplywiththerequirementsofIEC61215forcrystallinesilicon terrestrial PVmodules or IEC 61646 for thin-film terrestrial PVmodules. Inaddition,PVarrayjunctionbox,PVgeneratorjunctionboxandswitchgearassembliesshouldcomplywiththerequirementsofIEC60439-1.

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Chapter 4SOlAR PV SySteM InStAllAtIOn RequIReMentS

4.3 Application of Electrical Installation Licence

YourLEWwillbeabletoadviseyouwhetheryouneedtoapplytoEMAforanElectricalInstallation Licence for the use or operation of the electrical installation within thepremises of your building.

IfanElectricalInstallationLicenceisneeded,yourLEWwillsubmitthelicenceapplicationtoEMAonyourbehalf.IfyoualreadyhaveanElectricalInstallationLicenceissuedbyEMA,youneednotapplyforaseparatelicenceforthesolarPVsystemwithinthesamepremises.

The electrical licence fee payable to EMA is $100 per year (exclusive of goods andservicestax).

4.4 Conservation and Development Control Requirements

Atpresent, there isnospecific requirementorcontrolby theUrbanRedevelopmentAuthority (URA) on the use of installations such as a solar PV system.However,conservationprojects,orprojectswithintheCentralAreaaresubjecttoURAsUrbanDesignevaluationprocess.

Thestandarddevelopmentcontrolguidelinesapplytoprojectsthatmaynotbesubjectto conservation or urban design requirements, depending onwhich structure(s) thesolarPVsystemisinstalledonto.Forexample,ifasolarPVsystemisinstalledontherooftopofanattic,thentheatticguidelineswillapply.Likewise,ifasolarPVsystemisinstalledonraisedstructureslikeapavilion,thenthepavilionguidelineswillapply.

4.5 Guidelines on Conservation and Development Control

Architectsareadvisedtorefertotheconservationanddevelopmentcontrolguidelineswhen designing a development with a solar PV system installation. The respectiveguidelineisavailableatURAswebsite:

http://www.ura.gov.sg/conservation/Cons%20Guidelines.pdf http://www.ura.gov.sg/circulars/text/dchandbook.html

ShouldyouhavefurtherenquiriesonwhetheryourinstallationsconflictwiththeUrbanDesignorDevelopmentControlguidelines,youmaysubmityourenquiriestoURAeitherinpersonorthroughaQualifiedPerson(QP)aQPiseitheraregisteredarchitectoranengineerwiththeaccompanyingplansofthestructuresonwhichthesolarPVsystemwillbeinstalled:

Conservedbuildings Email:[email protected] Tel:63293355

Non-conservedbuildings Email:[email protected] Tel:62234811

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ShouldaformaldevelopmentapplicationtoURAberequired,itmustbemadeviaaQP.Thedetailscanbecheckedatthetwoweblinksbelow:

http://www.boa.gov.sg/register.html

http://www.peb.gov.sg/peb/process/searchPe

4.6 Structural Safety and Lightning Protection

Structural Safety

Toensuresafety,therearemeasuresandstepsthatneedtobetakenorconsideredwheninstallingasolarPVsystemontoaneworanexistingbuilding.Fornewbuildingdevelopments,thedesignofthestructuremusttakeintoconsiderationtheloadingofthesolarPVsysteminstallation,justlikeanyotherequipmentmountedontoabuildingstructure.

Forexistingbuildings,aprofessionalstructuralengineermayberequiredtocarryoutaninspectionoftheroofstructure,anddoacalculationonthestructuralloading.IftheroofisunabletowithstandtheloadingofthesolarPVsystem,structuralplanswillneedtobesubmittedtotheBuildingandConstructionAuthority(BCA)forapprovalbeforeabuildingpermitcanbeissuedforcommencementofinstallationworks.TheapplicationguidelineisavailableatthefollowingBCAswebsite:

http://www.bca.gov.sg/StructuralPlan/structural_plan_application.html

LightningProtection

Givenacertainlocation,solarPVsystemsareexposedtothethreatoflightningstrikes.As lightningcancausedamagetothePVmodulesand inverters,extracaremustbetakentoensurethatproperlightningprotectionisprovidedforthesolarPVsystemandthe entire structure. The inverters should be protected by appropriately rated surgearrestorsontheDCside.ItisgoodpracticetoalsoinstallsurgearrestorsontheACside.Structures and PV module frames must be properly grounded.

4.7 Connection to the Power Grid

If a solar PV system is designed tomeet only a fraction of the electricity load, thesystemwillneedtobeinterconnectedwiththepowergridtomeettheremainderoftheconsumers needs for electricity.

IfasolarPVsystemneedstobegrid-connected,interconnectioniskeytothesafetyofbothconsumersandelectricalworkers,andtotheprotectionofequipment.

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4.8 Get Connected to the Power Grid

IfyouintendtoconnectandoperateyoursolarPVsysteminparalleltothepowergrid,yourappointedLEWwillhave toconsultSPPowerGrid (SPPG)on theconnectionschemeandtechnicalrequirements.

The following documents set out the detailed consultation process and technical

requirements:

TheTransmissionCodeandtheMeteringCodearepublishedatEMAswebsite:

http://www.ema.gov.sg/media/files/codes_of_practice/electricity/transmission_code.pdf

http://www.ema.gov.sg/media/files/codes_of_practice/electricity/Metering_Code.pdf

SPPGs handbook, How to Apply for Electricity Connection, is published at SPPowerAssetswebsite:

http://www.sppowerassets.com.sg/PDF/howtoapply.pdf

4.9 Sale of Solar PV Electricity

Theexcesselectricitygeneratedfromagrid-connectedsolarPVcanbesoldbacktothepowergrid.ThearrangementsneededtoenablethissaleofsolarPVelectricityvary,dependingonwhetheryouareacontestableornon-contestableconsumer.

Consumers are classified, based on their average monthly electricity consumption,into:

Contestableconsumers:Theseconsumersarethenon-residentialconsumerswhousemorethan10,000kWhofelectricityamonth.Contestableconsumershaveachoiceofwhotheywishtobuytheirelectricityfrom.Theymaypurchaseelectricityfroma retailer, directly from thewholesalemarket (provided they are registeredwith the EnergyMarket Company asmarket participants) or indirectly from thewholesalemarketthroughSPServices.

Non-contestableconsumers:Theseconsumerscomprisealltheresidentialelectricity

usersandnon-residentialconsumerswhouselessthan10,000kWhofelectricityamonth.TheseconsumersaresuppliedwithelectricitybySPServices.

ContestableConsumers

If you are a contestable consumer generating electricity from a solar PV system and wishtosellandgetpaidfortheelectricityyouinjectintothepowergrid,youwillberequired to registerwith theEnergyMarketCompany (EMC) to participate in thewholesaleelectricitymarket,whichiscalledtheNationalElectricityMarketofSingaporeorNEMS.

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Chapter 4InStAllIng A SOlAR PV SySteM

figure 19. flowchart for electricity licences

Theflowchart inFigure19describes thecircumstancesunderwhich theGenerationLicenceorWholesaler(Generation)Licenceisrequired.

GenerationLicenceorWholesaler(Generation)Licencenotrequired

ApplytoEMAforGenerationLicence

ApplytoEMAforWholesaler

(Generation)Licence

ProposedGenerationUnit(e.g.Cogen,PVsystem,etc.)

GenerationCapacity

solar handbook

Documents

solar pv technology

solar pv yield

examples of solar pv

types of solar pv system

solar pv system contractor

appendix c

appendix b

installation angle