electric engineering handbook-01

Rahman,Saifur“ElectricPowerGeneration:Non-ConventionalMethods”TheElectricPowerEngineeringHandbookEd.L.L.GrigsbyBocaRaton:CRCPressLLC,20011ElectricPowerGeneration:Non-ConventionalMethodsSaifurRahmanVirginiaTech1.1WindPowerGaryL.Johnson1.2AdvancedEnergyTechnologiesSaifurRahman1.3PhotovoltaicsRogerA.Messenger©2001CRCPressLLC1ElectricPowerGeneration:Non-ConventionalMethods1.1WindPowerApplications•WindVariability1.2AdvancedEnergyTechnologiesStorageSystems•FuelCells•Summary1.3PhotovoltaicsTypesofPVCells•PVApplications1.1WindPowerGaryL.JohnsonThewindisafree,clean,andinexhaustibleenergysource.Ithasservedhumankindwellformanycenturiesbypropellingshipsanddrivingwindturbinestogrindgrainandpumpwater.Denmarkwasthefirstcountrytousewindforgenerationofelectricity.TheDaneswereusinga23-mdiameterwindturbinein1890togenerateelectricity.By1910,severalhundredunitswithcapacitiesof5to25kWwereinoperationinDenmark(Johnson,1985).Byabout1925,commercialwind-electricplantsusingtwo-andthree-bladedpropellersappearedontheAmericanmarket.ThemostcommonbrandswereWin-charger(200to1200W)andJacobs(1.5to3kW).Thesewereusedonfarmstochargestoragebatterieswhichwerethenusedtooperateradios,lights,andsmallapplianceswithvoltageratingsof12,32,or110volts.Agoodselectionof32-VDCapplianceswasdevelopedbytheindustrytomeetthisdemand.Inadditiontohomewind-electricgeneration,anumberofutilitiesaroundtheworldhavebuiltlargerwindturbinestosupplypowertotheircustomers.Thelargestwindturbinebuiltbeforethelate1970swasa1250-kWmachinebuiltonGrandpa’sKnob,nearRutland,Vermont,in1941.Thisturbine,calledtheSmith-Putnammachine,hadatowerthatwas34mhighandarotor53mindiameter.Therotorturnedanacsynchronousgeneratorthatproduced1250kWofelectricalpoweratwindspeedsabove13m/s.AfterWorldWarII,weenteredtheeraofcheapoilimportedfromtheMiddleEast.Interestinwindenergydiedandcompaniesmakingsmallturbinesfolded.Theoilembargoof1973servedasawakeupcall,andoil-importingnationsaroundtheworldstartedlookingatwindagain.ThetwomostimportantcountriesinwindpowerdevelopmentsincethenhavebeentheU.S.andDenmark(Broweretal.,1993).TheU.S.immediatelystartedtodeveloputility-scaleturbines.Itwasunderstoodthatlargeturbineshadthepotentialforproducingcheaperelectricitythansmallerturbines,sothatwasareasonabledecision.Thestrategyofgettinglargeturbinesinplacewaspoorlychosen,however.TheDepartmentofGaryL.JohnsonKansasStateUniversitySaifurRahmanVirginiaTechRogerA.MessengerFloridaAtlanticUniversity©2001CRCPressLLCEnergydecidedthatonlylargeaerospacecompanieshadthemanufacturingandengineeringcapabilitytobuildutility-scaleturbines.Thismeantthatsmallcompanieswithgoodideaswouldnothavetherevenuestreamnecessaryforsurvival.Theproblemwiththeaerospacefirmswasthattheyhadnodesiretomanufactureutility-scalewindturbines.Theygladlytookthegovernment’smoneytobuildtestturbines,butwhenthemoneyranout,theywerelookingforotherresearchprojects.Thegovernmentfundedanumberoftestturbines,fromthe100kWMOD-0tothe2500kWMOD-2.Theseranforbriefperiodsoftime,afewyearsatmost.Onceitwasobviousthataparticulardesignwouldneverbecostcompetitive,theturbinewasquicklysalvaged.Denmark,ontheotherhand,establishedaplanwherebyalandownercouldbuyaturbineandselltheelectricitytothelocalutilityatapricewheretherewasatleastsomehopeofmakingmoney.Theearlyturbineswerelargerthanwhatafarmerwouldneedforhimself,butnotwhatwewouldconsiderutilityscale.Thisprovidedarevenuestreamforsmallcompanies.Theycouldtrynewideasandlearnfromtheirmistakes.Manypeoplejumpedintothisnewmarket.In1986,therewere25windturbinemanufacturersinDenmark.TheDanishmarketgavethemabasefromwhichtheycouldalsoselltoothercountries.ItwassaidthatDenmarkledtheworldinexportsoftwoproducts:windturbinesandbuttercookies!TherehasbeenconsolidationintheDanishindustrysince1986,butsomeofthecom-panieshavegrownlarge.Vestas,forexample,hasmoreinstalledwindturbinecapacityworldwidethananyothermanufacturer.Priceshavedroppedsubstantiallysince1973,asperformancehasimproved.Itisnowcommonplaceforwindpowerplants(collectionsofutility-scaleturbines)tobeabletosellelectricityforunderfourcentsperkilowatthour.Totalinstalledworldwidecapacityatthestartof1999wasalmost10,000MW,accordingtothetrademagazineWindPowerMonthly(1999).Thecountrieswithover50MWofinstalledcapacityatthattimeareshowninTable1.1.ApplicationsThereareperhapsfourdistinctcategoriesofwindpowerwhichshouldbediscussed.Theseare1.small,non-gridconnected2.small,gridconnected3.large,non-gridconnected4.large,gridconnectedBysmall,wemeanasizeappropriateforanindividualtoown,uptoafewtensofkilowatts.Largereferstoutilityscale.TABLE1.1WindPowerInstalledCapacityCanada83China224Denmark1450India968Ireland63Italy180Germany2874Netherlands363Portugal60Spain834Sweden150U.K.334U.S.1952Other304Total9839©2001CRCPressLLCSmall,Non-GridConnectedIfonewantselectricityinalocationnotservicedbyautility,oneoftheoptionsisawindturbine,withbatteriestoleveloutsupplyanddemand.Thismightbeavacationhome,aremoteantennaandtransmittersite,oraThird-Worldvillage.Thecostswillbehigh,ontheorderof$0.50/kWh,butifthetotalenergyusageissmall,thismightbeacceptable.Thealt