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1、IntegratedScienceRenewableandNonrenewableenergysourcesIntroductionofsourcesofenergyNon-Renewable1.FossilFuels2.NuclearRenewable1.Wind2.Solar3.Tidal4.Hydropower5.5.GeothermalNon-Renewableenergysources:1.FossilFuelsWhatarefossilfuels?Afuelisanysubstanceusedasasourceofenergy,includingheating,transport,
2、electricitygenerationandotheruses.Mostoftheworldsenergyisprovidedbytheburningoffossilfuels(化石燃料).Coal, Oil and Gas are called fossil fuels”becausethey are natural combustible substances formedoriginallyfromdeadplantsandanimals.Themajorfossilfuelsarecoal(煤),petroleum(石油)andnaturalgas(天然氣).Fossils fue
3、ls are non-renewable (非再生能源) energy sources. This is because fossil fuels take millions of years to form. Once they are used up they can never be replaced.WorldFuelResourcesPetroleumorOilNaturalGasCoalPowerreserves130billiontonnes158billioncubicmetres950billiontonnesTotalusedin19902.2billiontonnes1.
4、5billioncubicmetres2.2billiontonnesFrom the above table, the present worlds estimated oil reserves may be used up in the next 50 to 60 years.CoalCoalistheplants,thatgrewinswampyareasabout300millionsago,diedtoformlayersofdecayingmaterial.Heat,pressureandtheactionofbacteriachangedthedecayingplantsinto
5、coal.Howitworks:Coaliscrushedtoafinedustandburnt.How is coal used?Today,about70%ofthetotalcoalminedisburnedinpowerstation.Coal Education (http:/www.coaleducation.org/) Petroleum1.How was petroleum formed?Petroleumwasformedfromsmallseaanimalsandplantsthatlivedmillionsofyearsago.Aftertheydied,heat;pre
6、ssure;andtheactionofbacteriachangedtheremainsintooil.Theoilformedwasthentrappedassmalldropsinsidetheporesofrocks.Petroleum (http:/www.petroleum.co.uk/) How is petroleum used?Thethickcrudeoilthatcomesfromthegroundisacomplexmixtureofcompounds.Itisnecessarytoseparatethecompounds.Theseparatedsubstancesh
7、avetwomainuses:assourcesofusefulfuels.e.g.petrolasrawmaterialstomakeotherproducts.e.g.plastics,detergents.ProductsMadefromaBarrelofCrudeOilNaturalGasNaturalgasisfoundtogetherwithoilandsometimeswithcoal.ThegasconsistsmainlyofmethaneCH4.Natural Gas (http:/www.naturalgas.org/) Source : www.naturalgas.o
8、rgInsomecountries,thegasiscarriedbypipestohomesandfactoriesforheatingandcooking.HOWNATURALGASISSTOREDANDDELIVEREDHow is petroleum used?TheadvantageanddisadvantagesofusingfossilfuelAdvantagesVerylargeamountsofelectricitycanbegeneratedinoneplaceusingcoal,fairlycheaply.Transportingoilandgastothepowerst
9、ationsiseasy.Gas-firedpowerstationsareveryefficient.Afossil-fuelledpowerstationcanbebuiltalmostanywhereDisadvantagesPollutionBurninganyfossilfuelproducescarbondioxide,whichcontributestothegreenhouseeffect,warmingtheEarth.Burningcoalproducesmorecarbondioxidethanburningoilorgas.Italsoproducessulphurdi
10、oxide,agasthatcontributestoacidrain.Wecanreducethisbeforereleasingthewastegasesintotheatmosphere.Miningcoalcanbedifficultanddangerous.Stripminingdestroyslargeareasofthelandscape.Non-Renewableenergysources:2.NuclearEnergyWhatareNuclearPower?Nuclear powerisgeneratedusingUranium,whichisametalminedinvar
11、iouspartsoftheworld.Somemilitaryshipsandsubmarineshavenuclearpowerplantsforengines.Nuclearpowerproducesaround11%oftheworldsenergyneeds,andproduceshugeamountsofenergyfromsmallamountsoffuel,withoutthepollutionthatyoudgetfromburningfossilfuelsHowitworksNuclearpowerstationsworkinprettymuchthesamewayasfo
12、ssilfuel-burningstations,exceptthatachainreactioninsideanuclearreactormakestheheatinstead.ThereactorusesUraniumrodsasfuel,andtheheatisgeneratedbynuclearfission.Neutronssmashintothenucleusoftheuraniumatoms,whichsplitroughlyinhalfandreleaseenergyintheformofheat.Carbondioxidegasispumpedthroughthereacto
13、rtotaketheheataway,andthehotgasthenheatswatertomakesteam.Thesteamdrivesturbineswhichdrivegenerators.Modernnuclearpowerstationsusethesametypeofturbinesandgeneratorsasconventionalpowerstations.AdvantagesNuclearpowercostsaboutthesameascoal,soitsnotexpensivetomake.Doesnotproducesmokeorcarbondioxide,soit
14、doesnotcontributetothegreenhouseeffect.Produceshugeamountsofenergyfromsmallamountsoffuel.Producessmallamountsofwaste.DisadvantagesItisvery,verydangerous.Itmustbesealedupandburiedformanyyearstoallowtheradioactivitytodieaway.Itisreliable,butalotofmoneyhastobespentonsafety-ifitdoesgowrong,anuclearaccid
15、entcanbeamajordisaster.Peopleareincreasinglyconcernedaboutthesafety.Renewableenergysources:1.WindIntroductionWeveusedthewindasanenergysourceforalongtime.WindpowerwasusedintheMiddleAges,inEurope,togrindcorn,whichiswherethetermwindmillcomesfrom. HowitworksThewindblowsthepropellorround,whichturnsagener
16、atortoproduceelectricity.Themoretowers,themorewind,andthelargerthepropellors,themoreelectricitywecanmake.Itsonlyworthbuildingwindfarmsinplacesthathavestrong,steadywinds,althoughboatsandcaravansincreasinglyhavesmallwindgeneratorstohelpkeeptheirbatteriescharged.AdvantagesWindisfree,windfarmsneednofuel
17、.Producesnowasteorgreenhousegases.Thelandbeneathcanusuallystillbeusedforfarming.Windfarmscanbetouristattractions.Agoodmethodofsupplyingenergytoremoteareas.DisadvantagesThewindisnotalwayspredictable-somedayshavenowind.Suitableareasforwindfarmsareoftennearthecoast,wherelandisexpensive.Somepeoplefeelth
18、atcoveringthelandscapewiththesetowersisunsightly.Cankillbirds-migratingflockstendtolikestrongwinds.Canaffecttelevisionreceptionifyoulivenearby.Canbenoisy.Renewableenergysources:2.SolarPowerIntroductionWeveusedtheSunfordryingclothesandfoodforthousandsofyears,butonlyrecentlyhavewebeenabletouseitforgen
19、eratingpower.JustthetinyfractionoftheSunsenergythathitstheEarth(aroundahundredthofamillionthofapercent)isenoughtomeetallourpowerneedsmanytimesover.Infact,everyminute,enoughenergyarrivesattheEarthtomeetourdemandsforawholeyear-ifonlywecouldharnessitproperly.HowitworksTherearetwomainwaysthatweusetheSun
20、senergy:-1.SolarCells-thatconvert2.lightdirectlyintoelectricity.3.2.Solarwaterheating,-where4.heatfromtheSunisusedto5.heatwateringlasspanels6.onyourroof.AdvantagesSolarenergyisfree-itneedsnofuelandproducesnowasteorpollution.Insunnycountries,solarpowercanbeusedwherethereisnoeasywaytogetelectricitytoa
21、remoteplace.Handyforlow-powerusessuchassolarpoweredgardenlightsandbatterychargersDisadvantagesDoesntworkatnight.Veryexpensivetobuildsolarpowerstations.Solarcellscostagreatdealcomparedtotheamountofelectricitytheyllproduceintheirlifetime.Canbeunreliableunlessyoureinaverysunnyclimate.IntheUnitedKingdom
22、,solarpowerisntmuchuseexceptforlow-powerapplications,asyouneedaverylargeareaofsolarpanelstogetadecentamountofpower.Renewableenergysources:3.TidalPowerIntroductionThetidemovesahugeamountofwatertwiceeachday,andharnessingitcouldprovideagreatdealofenergy-around20%ofBritainsneeds.Althoughtheenergysupplyi
23、sreliableandplentiful,convertingitintousefulelectricalpowerisnoteasy.ThereareeightmainsitesaroundBritainwheretidalpowerstationscouldusefullybebuilt,includingtheSevern,Dee,SolwayandHumberestuaries.Onlyaround20sitesintheworldhavebeenidentifiedaspossibletidalpowerstations.Howitworks:TidalBarragesThesew
24、orkratherlikeahydro-electricscheme,exceptthatthedamismuchbigger.Ahugedam(calledabarrage)isbuiltacrossariverestuary.Whenthetidegoesinandout,thewaterflowsthroughtunnelsinthedam.AdvantagesOnceyouvebuiltit,tidalpowerisfree.Itproducesnogreenhousegasesorotherwaste.Itneedsnofuel.Itproduceselectricityreliab
25、ly.Notexpensivetomaintain.Tidesaretotallypredictable.DisadvantagesAbarrageacrossanestuaryisveryexpensivetobuild,andaffectsaverywidearea-theenvironmentischangedformanymilesupstreamanddownstream.Manybirdsrelyonthetideuncoveringthemudflatssothattheycanfeed.Therearefewsuitablesitesfortidalbarrages.Onlyp
26、rovidespowerforaround10hourseachday,whenthetideisactuallymovinginorout.Renewableenergysources:4.HydropowerIntroductionWehaveusedrunningwaterasanenergysourceforthousandsofyears,mainlytogrindcorn.Thefirstuseofwatertogenerateelectricitywasin1882ontheFoxriver,intheUSA,whichproducedenoughpowertolighttwop
27、apermillsandahouse.Nowadaystherearemanyhydro-electricpowerstations,providingaround20%oftheworldselectricity.Thenamecomesfromhydro,theGreekwordforwater.HowitworksAdamisbuilttotrapwater,usuallyinavalleywherethereisanexistinglake.Waterisallowedtoflowthroughtunnelsinthedam,toturnturbinesandthusdrivegene
28、rators.Noticethatthedamismuchthickeratthebottomthanatthetop,becausethepressureofthewaterincreaseswithdepth.AdvantagesOncethedamisbuilt,theenergyisvirtuallyfree.Nowasteorpollutionproduced.Muchmorereliablethanwind,solarorwavepower.Watercanbestoredabovethedamreadytocopewithpeaksindemand.Hydro-electricp
29、owerstationscanincreasetofullpowerveryquickly,unlikeotherpowerstations.Electricitycanbegeneratedconstantly.DisadvantagesThedamsareveryexpensivetobuild.However,manydamsarealsousedforfloodcontrolorirrigation,sobuildingcostscanbeshared.Buildingalargedamwillfloodaverylargeareaupstream,causingproblemsfor
30、animalsthatusedtolivethere.Findingasuitablesitecanbedifficult-theimpactonresidentsandtheenvironmentmaybeunacceptable.Waterqualityandquantitydownstreamcanbeaffected,whichcanhaveanimpactonplantlifeRenewableenergysources:5.GeothermalIntroductionThecentreoftheEarthisaround6000degressCelsius-hotenoughtom
31、eltrock.Evenafewkilometresdown,thetemperaturecanbeover250degreesCelsius.Ingeneral,thetemperaturerisesonedegreeCelsiusforevery36metresyougodown.Involcanicareas,moltenrockcanbeveryclosetothesurface.Geothermalenergyhasbeenusedforthousandsofyearsinsomecountriesforcookingandheating.Thenamegeothermalcomes
32、fromtwoGreekwords:geomeansEarthandthermalmeansheat.HowitworksHotrocksundergroundheatwatertoproducesteam.Wedrillholesdowntothehotregion,steamcomesup,ispurifiedandusedtodriveturbines,whichdriveelectricgenerators.Theremaybenaturalgroundwaterinthehotrocksanyway,orwemayneedtodrillmoreholesandpumpwaterdow
33、ntothem.AdvantagesGeothermalenergydoesnotproduceanypollution,anddoesnotcontributetothegreenhouseeffect.Thepowerstationsdonottakeupmuchroom,sothereisnotmuchimpactontheenvironment.Nofuelisneeded.Onceyouvebuiltageothermalpowerstation,theenergyisalmostfree.Itmayneedalittleenergytorunapump,butthiscanbeta
34、kenfromtheenergybeinggeneratedDisadvantagesThebigproblemisthattherearenotmanyplaceswhereyoucanbuildageothermalpowerstation.Youneedhotrocksofasuitabletype,atadepthwherewecandrilldowntothem.Thetypeofrockaboveisalsoimportant,itmustbeofatypethatwecaneasilydrillthrough.Sometimesageothermalsitemayrunoutofsteam,perhapsfordecades.Hazardousgasesandmineralsmaycomeupfromunderground,andcanbedifficulttosafelydisposeof.ConclusionThoughtherearemoreandmorerenewableenergysources,savingenergyisveryimportant.
