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1、IELTSADVANTAGEShortAnswerQuestionsStrategyPracticeAustraliaswindenergyresourcesWindisavastpotentialsourceofrenewableenergy.Windsaregeneratedbycomplexmechanismsinvolvingtherotationoftheearth,theheatcapacityofthesun,thecoolingeffectoftheoceansandpolaricecaps,temperaturegradientsbetweenlandandsea,andth
2、ephysicaleffectsofmountainsandotherobstacles.Windenergyisgeneratedbyconvertingwindcurrentsintootherformsofenergyusingawindturbine.Turbinesextractenergyfromthepassingairbyconvertingkineticenergyfromrotationalmovementviaarotor.Theeffectivenessofthisconversionatanygivensiteiscommonlymeasuredbyitsenergy
3、densityor,alternatively,asacapacityfactor.Windenergyisprimarilyusedforelectricitygeneration,bothonsiteandfortransporttothegrid.Windenergyisalsousedtopumpborewater,particularlyinruralareas.Thewindenergyindustryisthefastestgrowingrenewableenergysourceinmanycountriesandisexpectedtocontinuetogrowrapidly
4、overtheperiodto2030.ProductionofwindenergyislargelyconcentratedinEuropeandtheUnitedStates.However,therehasalsobeenrapidgrowthinthewindenergyindustriesinChinaandIndia.TheworldswindenergyresourceisestimatedtobeaboutonemillionGWfortotallandcoverage.Assumingonly1percentoftheareaisutilisedandallowanceism
5、adeforthelowerloadfactorsofwindplants,thewindenergypotentialwouldcorrespondtoaroundtheworldtotalelectricitygenerationcapacity.Thewindiestareasaretypicallycoastalregionsofcontinentsatmid-tohighlatitudesandinmountainousregions.Locationswiththehighestwindenergypotentialincludethewesterlywindbeltsbetwee
6、nlatitudes35oand50o.ThisincludesthecoastalregionsofwesternandsouthernAustralia,NewZealand,southernSouthAmerica,andSouthAfricainthesouthernhemisphere,andnorthernandwesternEurope,andthenortheasternandwesterncoastsoftheUnitedStates.Theseregionsaregenerallycharacterisedbyhigh,relativelyconstantwindcondi
7、tions,withaveragewindspeedsinexcessof6metrespersecond(ms)and,inplaces,morethan9ms.Regionswithhighwindenergypotentialarecharacterisedby: highaveragewindspeeds; windsthatareeitherconstantorcoincidingwithpeakenergyconsumptionperiods(duringthedayorevening); proximitytoamajorenergyconsumptionregion;IELTS
8、ADVANTAGEShortAnswerQuestionsStrategyPractice smoothlandscape,whichincreaseswindspeeds,andreducesthemechanicalstressonwindturbinecomponentsthatresultsfromvariableandturbulentwindconditionsassociatedwithroughlandscape.Becauseofwindvariability,theenergydensityatapotentialsite-commonlydescribedasitscap
9、acityfactor-isgenerallyintherangeof20-40percent.Whilethemajorityofareasinlocationsconvenientforelectricitytransfertothegridarelocatedonshore,offshoresiteshavealsobeenidentifiedashavingsignificantpotentialforwindenergy,bothtotakeadvantageofincreasedwindspeedsandtoincreasethenumberofavailablesites.Off
10、shorelocationsalsohelpreduceturbulenceand,hence,stressonmachinecomponents.TherehavebeenwindturbinesdeployedinshallowseasoffnorthernEuropeformorethanadecade.Offshoresitesareexpectedtomakeanincreasinglysignificantcontributiontoelectricitygenerationinsomecountries,notablyinEuropebecauseinEuropethereare
11、increasingdifficultiesingainingaccesstoonshoresites.Australiahassomeofthebestwindresourcesintheworld.Australiaswindenergyresourcesarelocatedmainlyinthesouthernpartsofthecontinent(whichlieinthepathofthewesterlywindflowknownastheroaring40s)andreachamaximumaroundBassStrait.Thelargestwindresourceisgener
12、atedbythepassageoflowpressureandassociatedfrontalsystems,whosenortherlyextentandinfluencedependsonthesizeofthefrontalsystem.WindsinnorthernAustraliaarepredominantlygeneratedbythemonsoonandtradewindsystems.Large-scaletopographysuchastheGreatDividingRangeineasternAustraliaexertsignificantsteeringeffec
13、tsonthewinds,channellingthemthroughmajorvalleysordeflectingorblockingthemfromotherareas.DeflectionofweakerfrontsfromfrontalrefractionaroundtherangesoftheDivideinsoutheasternAustraliacreateswindswithasoutherlycomponent(southerlybusters,)alongtheeastcoast.Inadditiontotherefractionsbytopographyandheatl
14、owsovernorthernAustralia,othermajorfactorsinfluencingwindresourcesareseasonalanddiurnalvariationinwindspeed.WindsarestrongestinwinterandspringinwesternandsouthernAustraliabutthemonthlybehaviourdiffersfromregiontoregion.Variationsinaveragemonthlywindspeedofupto15-20percentoverthelongtermannualaverage
15、arenotuncommon.Theremaybesimilardailyvariationsatindividuallocations,withincreasedwindspeedsintheafternoon.Meso-scalemapsshowthatAustraliasgreatestwindpotentialliesinthecoastalregionsofwestern,south-western,southernandsouth-easternAustralia.Coastalregionswithhighwindresources(windspeedsabove7.5ms)in
16、cludethewestcoastsouthofSharkBaytoCapeLeeuwin,alongtheGreatAustralianBightandtheEyrePeninsulainSouthAustralia,towesternVictoriaandthewestcoastofTasmania.GoodwindresourcesextendhundredsofkilometresinlandandmanyofAustraliaswindfarms(currentandplanned)arelocatedsomedistancefromthecoast.InlandIELTSADVANTAGEShortAnswerQuestionsStrategyPracticeregionsofWesternAustralia,SouthAustraliaandwesternVictoriaallhavegoodwindresources.Areaswithhig