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In a turbine generator, a moving fluid—water, steam, combustion gases, or air—pushes a series of blades mounted on a rotor shaft. The force of ... Electricityexplained Howelectricityisgenerated Basics +Menu Whatisenergy? Unitsandcalculators U.S.energyfacts Useofenergy Energyandtheenvironment Close Whatisenergy? 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Electromagneticgeneratorsuseanelectromagnet—amagnetproducedbyelectricity—notatraditionalmagnet.Abasicelectromagneticgeneratorhasaseriesofinsulatedcoilsofwirethatformastationarycylinder—calledastator—surroundinganelectromagneticshaft—calledarotor.Turningtherotormakesanelectriccurrentflowineachsectionofthewirecoil,whichbecomesaseparateelectricconductor.Thecurrentsintheindividualsectionscombinetoformonelargecurrent.Thiscurrentistheelectricitythatmovesfromgeneratorsthroughpowerlinestoconsumers.Electromagneticgeneratorsdrivenbykinetic(mechanical)primemoversaccountfornearlyallofU.S.electricitygeneration. Turbinedrivengenerators MostofU.S.andworldelectricitygenerationisfromelectricpowerplantsthatuseaturbinetodriveelectricitygenerators.Inaturbinegenerator,amovingfluid—water,steam,combustiongases,orair—pushesaseriesofbladesmountedonarotorshaft.Theforceofthefluidonthebladesspins/rotatestherotorshaftofagenerator.Thegenerator,inturn,convertsthemechanical(kinetic)energyoftherotortoelectricalenergy.Differenttypesofturbinesincludesteamturbines,combustion(gas)turbines,hydroelectricturbines,andwindturbines. Steamturbinesareusedtogeneratethemajorityoftheworld’selectricityandtheyaccountedforabout44%ofU.S.electricitygenerationin2020.Moststeamturbineshaveaboilerinwhichafuelisburnedtoproducehotwaterandsteaminaheatexchanger,andthesteampowersaturbinethatdrivesagenerator.Nuclearpowerreactorsusenuclearfuelrodstoproducesteam.Solarthermalpowerplantsandmostgeothermalpowerplantsusesteamturbines.MostofthelargestU.S.electricpowerplantsusesteamturbines. Combustiongasturbines,whicharesimilartojetengines,burngaseousorliquidfuelstoproducehotgasestoturnthebladesintheturbine. Steamandcombustionturbinescanbeoperatedasstand-alonegeneratorsinasingle-cycleorcombinedinasequentialcombined-cycle.Combined-cyclesystemsusecombustiongasesfromoneturbinetogeneratemoreelectricityinanotherturbine.Mostcombined-cyclesystemshaveseparategeneratorsforeachturbine.Insingle-shaftcombinedcyclesystems,bothturbinesmaydriveasinglegenerator.Learnmoreaboutdifferenttypesofcombined-cyclepowerplants.In2020,combined-cyclepowerplantssuppliedabout35%ofU.S.netelectricitygeneration. Combined-heat-and-power(CHP)plants,whichmaybereferredtoascogenerators,usetheheatthatisnotdirectlyconvertedtoelectricityinasteamturbine,combustionturbine,oraninternalcombustionenginegeneratorforindustrialprocessheatorforspaceandwaterheating.MostofthelargestCHPplantsintheUnitedStatesareatindustrialfacilitiessuchaspulpandpapermills,buttheyarealsousedatmanycolleges,universities,andgovernmentfacilities.CHPandcombined-cyclepowerplantsareamongthemostefficientwaystoconvertacombustiblefuelintousefulenergy. Hydroelectricturbinesusetheforceofmovingwatertospinturbinebladestopoweragenerator.Mosthydroelectricpowerplantsusewaterstoredinareservoirordivertedfromariverorstream.Theseconventionalhydroelectricpowerplantsaccountedforabout7%ofU.S.electricitygenerationin2020.Pumped-storagehydropowerplantsusethesametypesofhydroturbinesthatconventionalhydropowerplantsuse,buttheyareconsideredelectricitystoragesystems(seebelow).Othertypesofhydroelectricturbinescalledhydrokineticturbinesareusedintidalpowerandwavepowersystems.Learnmoreaboutdifferenttypesofhydroelectricturbines. Windturbinesusethepowerinwindtomovethebladesofarotortopoweragenerator.Therearetwogeneraltypesofwindturbines:horizontalaxis(themostcommon)andvertical-axisturbines.Windturbineswerethesourceofabout8%ofU.S.electricitygenerationin2020. Oceanthermalenergyconversion(OTEC)systemsuseatemperaturedifferencebetweenoceanwateratdifferentdepthstopoweraturbinetoproduceelectricity. Othertypesofgenerators Therearemanydifferenttypesofelectricitygeneratorsthatdonotuseturbinestogenerateelectricity.Themostcommoninusetodayaresolarphotovoltaic(PV)systemsandinternalcombustionengines. Solarphotovoltaiccellsconvertsunlightdirectlyintoelectricity.Theyareusedtopowerdevicesassmallaswristwatchesandcanbeconnectedtogetherinpanelsthatareconnectedtogetherinarraystopowerindividualhomesorformlargepowerplants.Photovoltaic(PV)powerplantsarenowoneofthefastestgrowingsourcesofelectricitygenerationaroundtheworld.IntheUnitedState,PVpowerplantswerethesourceofabout2%oftotalutility-scaleelectricitygenerationin2020. Internalcombustionengines,suchasdieselengines,areusedallaroundtheworldforelectricitygenerationincludinginmanyremotevillagesinAlaska.Theyarealsowidelyusedformobilepowersupplyatconstructionsitesandforemergencyorbackuppowersupplyforbuildingsandpowerplants.Diesel-enginegeneratorscanuseavarietyoffuelsincludingpetroleumdiesel,biomass-basedliquidfuelsandbiogas,naturalgas,andpropane.Smallinternalcombustionenginegeneratorsfueledwithgasoline,naturalgas,orpropanearecommonlyusedbyconstructioncrewsandtradespeopleandforemergencypowersupplyforhomes. Othertypesofelectricitygeneratorsincludefuelcells,Stirlingengines(usedinsolarthermalparabolic-dishgenerators),andthermoelectricgenerators. Energystoragesystemsforelectricitygenerationincludehydro-pumpedstorage,compressed-airstorage,electrochemicalbatters,andflywheels.Theseenergystoragesystemsuseelectricitytochargeastoragefacilityordevice,andtheamountofelectricitythattheycansupplyislessthantheamounttheyuseforcharging.Therefore,thenetelectricitygenerationfromstoragesystemsiscountedasnegativetoavoiddoublecountingelectricityuseforchargingthestoragesystem. ElectricitygeneratorsbymajortypeandshareoftotalannualU.S.utility-scalenetelectricitygenerationin20201 Generator Planttype Mainfuel/energysource Shareofannualelectricitygeneration Steamturbine Singlecycle Allsources 43.9% Coal 19.1% Nuclear 19.7% Naturalgas   2.7% Biomass(1.1%);Others(1.3%)   2.4% Multiple Combinedcycle Naturalgas2 34.5% Combustionturbine 22.0% Steamturbine 11.1% Dual/singleshaft   1.5% Combustiongasturbine Singlecycle Naturalgas2   3.4% Windturbine Alltypes Wind   8.4% Hydroelectricturbine Conventional Water   7.1% Photovoltaic Alltypes Solar   2.1% Others3 Various   0.6% Storagesystems4 Various  -0.1% 1Includesgeneratorsatpowerplantswithatleastonemegawattelectricgenerationcapacity. 2Naturalgasisthemainenergysource(99%)forcombined-cyclepowerplants. 3Othersourcesincludeinternalcombustionengines,fuelcells,andbinary-cycleturbines. 4Storagesystemsincludehydro-pumpedstorage,electrochemicalbatteries,compressed-airstorage,andflywheels.Generationfromstoragesystemsisnettedoutoftotalannualelectricitygenerationtoavoiddoublecountingofenergystoragechargingsources. Source:U.S.EnergyInformationAdministration(EIA),FormEIA-923PowerPlantOperationsReport,2020 Lastupdated:November1,2021 Electricity Thescienceofelectricity Magnetsandelectricity Batteries,circuits,andtransformers Measuringelectricity Howelectricityisgenerated ElectricityintheUnitedStates Generation,capacity,andsales Deliverytoconsumers Useofelectricity Pricesandfactorsaffectingprices Electricityandtheenvironment BillNyetheScienceGuydemonstrateshowanelectromagnetworks(video) Howdoesanelectricgeneratorwork? SmallThermoelectricGenerators Articlesonelectricity Photovoltaicsandelectricity U.S.energyfacts Useofenergy WhatisU.S.electricitygenerationbyenergysource? GeneralenergyFAQs