Basicconcepts
Marineenergyisakindofrenewableenergycontainedintheocean,includingtidalenergy,mechanicalenergyandthermalenergycausedbywaves.Oceanenergyalsoinvolvesabroadercategory,includingwindenergyoverthesea,solarenergyontheseasurfaceandbiomassenergyinthesea.Chinahas18,000kilometersofcoastlineand6,960islandswithatotalareaof6,700squarekilometers.Mostoftheseislandsarefarawayfromthelandandthereforelackenergysupply.Therefore,inordertorealizethesustainabledevelopmentofmycountry'scoastalandislandeconomy,wemustvigorouslydevelopmycountry'soceanenergyresources.
Океанската енергия се отнася до възобновяема енергия, свързана с това море. Океанът получава, съхранява и отделя енергия чрез различни физически процеси. Тази енергия съществува под формата на приливи и отливи, вълни, температурни разлики, градиенти на соленост, океански течения и т.н. В океана. Площта на земната повърхност е около 5,1×10< sup>8km2, от които земната повърхност е1. 49×108km229%;океанската зона достига 3,61×108km2. По отношение на нивото на морето, средната надморска височина на водопада е около 840m, докато средната дълбочина на океана е 380 м. Обемът на цялата морска вода е 1,37×109km3.Безкрайното море само осигурява на хората корабоплаване, вода и богати минерални залежи, но също така съдържа огромна енергия. механична енергия в морето, за разлика от сушата и въздуха.
Seawatertemperaturedifferenceenergyisakindofheatenergy.Theseasurfaceatlowlatitudeshasahighertemperature,whichcreatesatemperaturedifferencewiththedeepwater,whichcancauseheatexchange.Itsenergyisproportionaltothesizeofthetemperaturedifferenceandtheamountofheatexchangewater.Tidalenergy,tidalcurrentenergy,oceancurrentenergy,andwaveenergyareallmechanicalenergy.Theenergyofthetideisproportionaltothesizeofthetidalrangeandthetidalvolume.Theenergyofawaveisproportionaltothesquareofthewaveheightandtheareaofthewavedwaterarea.Thereisstillseawatersalinityenergy(alsoknownasseawaterchemicalenergy)intheestuarywaters,andthereisasalinitydifferencebetweenthefreshwaterthatenterstheseaandtheoceansaltwater.Ifasemi-permeablemembraneisused,thefreshwaterpenetratestotheseawaterside
,Cangenerateosmoticpressure,anditsenergyisproportionaltothepressuredifferenceandtheosmoticenergy.
Енергийни характеристики
1.Енергията на океана има огромни резерви в общото водно тяло на океана, докато енергията на единица обем, единица площ и дължина на единица е сравнително малка. Това означава, че ако искате да получите голяма енергия, трябва да получите от много морска вода.
2.Oceanenergyisrenewable.Oceanenergycomesfromthegravitationalforcebetweensolarradiationenergyandcelestialbodies.Aslongasthesun,moonandothercelestialbodiescoexistwiththeearth,thiskindofenergywillberegenerated,anditwillbeinexhaustibleandinexhaustible.
3.Oceanenergycanbedividedintorelativelystableandunstableenergysources.Themorestableonesaretemperaturedifferenceenergy,salinitydifferenceenergyandoceancurrentenergy.Unstableenergyisdividedintotwotypes:regularchangesandirregularchanges.Tidalenergyandtidalenergyareunstablebutchangeregularly.Accordingtothechanginglawsoftidesandtides,peoplecompiletideandtideforecastsdaybydayandhourbydayinvariousplaces,andpredictthesizeandstrengthoftidesatvarioustimesinthefuture.Tidalpowerstationsandtidalpowerstationscanbearrangedforpowergenerationandoperationaccordingtotheforecasttable.Whatisunstableandirregulariswaveenergy.
4.Океанската енергия е източник на чиста енергия, т.е. след като океанската енергия е разработена, тя има малко въздействие върху замърсяването на околната среда.
Energyform
Tidalenergy
Tidalenergyreferstothepotentialenergygeneratedduringhightideandlowtide.Theintensityoftidalenergyisrelatedtothenumberoftidalheadsandthedrop.Generally,tideswithaheaddropgreaterthan3mhavethevalueofcapacityutilization.Tidalenergyismainlyusedforpowergeneration.
Waveenergy
Waveenergyreferstothekineticenergyandpotentialenergyofwavesonthesurfaceoftheocean.Itisgeneratedundertheactionofwindandisderivedfrompotentialenergyandkineticenergy.Mechanicalenergystoredinshort-periodwaves.Waveenergyismainlyusedforpowergeneration,butcanalsobeusedtotransportandpumpwater,heating,seawaterdesalinationandhydrogenproduction.
Temperaturedifferenceenergy
Seawatertemperaturedifferenceenergyreferstothethermalenergyofthedifferenceinwatertemperaturebetweenoceansurfacewateranddeepoceanwater,andisanimportantformofoceanenergy.Theseasurfaceatlowlatitudeshasahigherwatertemperature,andthereisatemperaturedifferencewiththedeepcoldwater,andthethermalenergyofthetemperaturedifferenceisstored,anditsenergyisproportionaltothesizeofthetemperaturedifferenceandtheamountofwater.
Themainuseoftemperaturedifferenceenergyispowergeneration.TheFrenchphysicistAssonvalfirstproposedtheideaofusingseawatertemperaturedifferencetogenerateelectricity.In1926,Assonvale’sstudentClaudesuccessfullyexperimentedwithseawatertemperaturedifferencepowergeneration.In1930,Claudebuilttheworld'sfirstseawatertemperaturedifferencepowerstationontheCubancoast,andobtained10kWofpower.
Thebiggestdifficultyintheuseoftemperaturedifferenceenergyisthesizeofthetemperaturedifference,lowenergydensity,itsefficiencyisonlyabout3%,andtheheatexchangeareaislarge,andtheconstructioncostishigh.Countriesarestillactivelyexploring.
Salinitydifferenceenergy
Saltdifferenceenergyreferstothechemicalpotentialdifferenceenergybetweenseawaterandfreshwaterorbetweentwoseawaterswithdifferentsaltconcentrations,whichappearsintheformofchemicalenergyOceanEnergy.Itmainlyexistsatthejunctionoftheriverandthesea.Atthesametime,saltlakesandundergroundsaltminesinfreshwater-richareascanalsousesaltdifferenceenergy.Salinityenergyisakindofrenewableenergywiththehighestenergydensityinoceanenergy.
Itisestimatedthatthesaltdifferenceintheestuariesoftheworldcanreach30TW,and2.6TWmaybeused.Thesalinitydifferenceinmycountryisestimatedtobe1.1×10^8kw,whichismainlyconcentratedintheoutletsofmajorrivers.Atthesametime,therearestillmanyinlandsaltlakesinmycountry'sQinghaiProvinceandotherplacesthatcanbeused.TheresearchonsaltdifferenceenergyisbasedontheresearchoftheUnitedStatesandIsrael,andsomeresearcheshavealsobeencarriedoutinChina,SwedenandJapan.Butingeneral,theresearchonthenewenergyofsaltdifferenceenergyisstillattheleveloflaboratoryexperiments,andthereisstillalongwaytogobeforedemonstrationapplications.
Currentenergy
Currentenergyreferstothekineticenergyofseawaterflow,mainlyreferstotherelativelystableflowinsubmarinewaterwaysandstraits,andtheregularflowofseawatercausedbytides.Energyisanotheroceanenergythatappearsintheformofkineticenergy.
Theuseofoceancurrentenergyismainlypowergeneration,anditsprincipleissimilartowindpowergeneration.Thetheoreticalestimateofoceancurrentenergyintheworldisabout108kW.Usingvariousobservationsandanalysisdataof130waterwaysandnavigationgatesalongthecoastofChina,calculationsandstatisticshaveobtainedthetheoreticalvalueoftheannualaveragepowerofChina'scoastaloceancurrentstobeabout1.4X107kW.Itisoneoftheregionswiththehighestpowerdensityintheworld.TheoceancurrentsalongthecoastsofLiaoning,Shandong,Zhejiang,FujianandTaiwanaremoreabundant.Manywaterwayshaveenergydensitiesof15-30kW/m2.Gooddevelopmentvalue.EspeciallyintheJintang,GuishanandXihoumenwaterwaysofZhoushanIslandsinZhejiangProvince,theaveragepowerdensityisabove20kW/m2,andthedevelopmentenvironmentandconditionsareverygood.
Seawindenergy
Offshorewindenergyisthekineticenergygeneratedbythelargeamountofairmovementonthesurfaceoftheearth.Ontheocean,thewindisstrongerthanonland,andthedirectionismoreuniform.Accordingtoexpertestimates,anoceanwindturbinewiththesamepowercanproduce70%moreelectricityinayearthanalandwindturbine.Theprincipleofwindpowergeneration:windactsontheimpellertoconvertkineticenergyintomechanicalenergy,therebydrivingtheimpellertorotate,andthenthespeedofrotationisincreasedbythespeedincreasertopromotethegeneratortogenerateelectricity.mycountry'soffshorewindenergyresourcesarethreetimesthatofonshorewindenergyresources,andthereare750millionkWofwindenergyreservesthatcanbedevelopedandutilized.ThesoutheastcoastanditsislandsbetweentheYangtzeRiverandNan'aoIslandaremycountry'slargestwindenergyresourceareaandanarearichinwindenergyresources.Theresource-richareasincludeShandong,theLiaodongPeninsula,thecoastoftheYellowSea,thecoastoftheSouthChinaSeawestofNanaoIsland,HainanIslandandtheSouthChinaSeaIslands
OceanThermalEnergy
MarinethermalenergyreferstothecombinationofoceansurfacewaterbodiesandThermalenergycausedbytemperaturedifferencesindeepwaterbodies.Inadditiontopowergeneration,oceanthermalenergycanalsobeusedforseawaterdesalination,airconditioning,anddeep-seamineraldepositdevelopment.
Предимства и недостатъци
Недостатъци: Няма консенсус относно най-добрия начин за получаване на енергия. Мащабните проекти могат да навредят на естествените водни потоци, приливите и екосистемите.
Предимства: Неизчерпаеми възобновяеми ресурси, енергията от приливите и отливите трябва да се следва и мащабът на развитие може да бъде голям или малък.
Marineenergyresourcesgenerallyrefertotherenewablenaturalenergycontainedintheocean,includingtidalenergy,waveenergy,oceancurrentenergy(tidalenergy),seatemperaturedifferenceenergy,seasaltdifferenceenergy,etc.Theseenergysourceshavetheadvantagesofbeingrenewableandnon-pollutingtheenvironment,andareanewenergysourceofstrategicsignificancethaturgentlyneedstobedevelopedandutilized.
Wavepowergeneration,accordingtoscientists,theelectricenergycontainedinwavesontheearthisashighas90trilliondegrees.Largewavegeneratorsetshavealsocomeout.mycountryisalsoconductingresearchandtestingonwavepowergeneration,andmadepowergenerationdevicesfornavigationlights.Inthefutureworld,therewillbewavepowerplantsbelongingtoChinaineveryocean.Waveenergywillmakeagreatcontributiontomycountry'selectricalindustry.
Tidalpowergeneration,accordingtoestimatesbytheWorldPowerConference,by2020,theworld’stidalpowergenerationwillreach100-300billionkilowatts.ThelargesttidalpowerstationintheworldistheRanceEstuaryPowerStationontheEnglishChannelinnorthernFrance.Ithasageneratingcapacityof240,000kilowattsandhasbeeninoperationformorethan30years.ChinabuilttheJiangxiatidalpowerstationinZhejiangProvincewithatotalcapacityof3,000kilowatts.
Използване на енергия
Метод на оползотворяване
Има два начина за генериране на топлинна енергия от океана:
ThefirstoneistoheatthelowboilingpointworkingfluidIntosteam;
Thesecondistosendwarmwaterdirectlyintothevacuumchambertomakeitboilandturnintosteam.Thesteamisusedtodrivethesteamturbinegeneratortogenerateelectricity.Finally,coldwaterispumpedfromadepthof600to1000meterstocondensethesteam.
Първият камък приема затворен цикъл, а вторият приема без отворен цикъл.
ThefirsttestwassuccessfulinFrancein1930,buttheelectricitygeneratedatthattimewasnotaslargeastheelectricityconsumed,soitcouldnotbeimplemented.Manycountriesareconductingresearchonseawatertemperaturedifferencepowergeneration.Practicehasprovedthattheopencyclehasmoreadvantagesthantheclosedcycle:①Usingwarmseawaterastheworkingmedium,itcanavoidthepollutionoftheoceanbytoxicsubstancessuchasammoniaordichlorodifluoromethane;②TheopencyclesystemdirectlycontactstheheatexchangeTheheatexchangerischeapandefficient;③Thedirectcontactheatexchangercanbemadeofplastic,whichhashighcorrosionresistanceinwarmseawater;④Itcanproduceby-product-distilledwater.Theopencyclealsohasdisadvantages:thedensityofsteamproducedislow,andthesteamturbineislarge;aftertheseawaterthatturnsintosteamisdischargedbacktotheocean,itwillaffectthelivingenvironmentofnearbyorganisms.
1.Производство на топлинна енергия
Usinganon-azeotropicmedium(amixtureofFreon-22andFreon-12)asthemedium,theoutputpoweris1.1to1.2timestheprevious.Thetrialoperationofa75-kilowattpilotplantprovedthatbecausetheheatexchangeradoptsaflatplatedevice,therequiredpumpingcapacityissmall,thetransmissionpowerconsumptionissmall,andthecostofotheraccessoriesisalsolow.Inaddition,thenetelectricoutputpowercanbecontrolledbyacomputer.Upto70%oftheratedpower.A3,000-kilowatt-classpowerstationcostslessthan50yenperkilowatt-hourofpowergeneration,whichislowerthanthepriceofdieselpowergeneration.Itispredictedthattheuseofoceantemperaturedifferencetogenerateelectricity,ifitcanberealizedwithinacentury,canbecomeanewstartingpointforthedevelopmentofnewenergy.
2.Производство на приливна енергия
Intheturbulentsea,undertheinfluenceofthesunandmoon,thetidesometimesrisesbyhundredsoffeetandsometimesquietlyrecedes,leavingbehindasandybeach.Theoceanundulateslikethis,dayandnight,yearafteryear,soregular,sorhythmic,asifpeoplearebreathing.Thisregularfluctuationofseawateriscalledtides.
Tidalpowergenerationisanimportantwaytoutilizetidalenergy.Accordingtopreliminaryestimates,therearemorethan1billionkilowattsoftidalenergyintheworld,whichcangenerate2to3trillionkilowatt-hoursofelectricityeachyear.mycountry’scoastlineis18,000kilometerslong.Accordingtotheresultsofthe1958Census,itisestimatedthatthereareatleast28millionkilowattsoftidalpowerresources,andtheminimumannualpowergenerationcapacityisnolessthan70billionkilowatt-hours.
Световноизвестната идея за зона е Английският канал, където най-високият диапазон на приливите и отливите е 14,6 метра, а диапазонът на приливите и отливите по протежение на Атлантическия океан също от 4 до 7,4 метра. Диапазонът на приливите и отливите на „Qiantang Tide“ в Hangzhou Bay в моята страна е 9 метра.
ItisestimatedthatonlythenorthbranchoftheYangtzeRiverestuarycanbuild800,000-kilowatttidalpowerstationsinChina,withanannualpowergenerationof2.3billionkWh,whichisclosetothetotalpowergenerationcapacityofXin'anRiverandFuchunRiverhydropowerstations;QiantangRiverestuarycanbebuiltThe5millionkilowatttidalpowerstationhasanannualpowergenerationcapacityofmorethan18billionkilowatt-hours,whichisapproximatelyequivalenttothepowergenerationcapacityof10Xin'anjianghydropowerstations.
Asearlyasthe12thcentury,humansbegantousetidalenergy.A"tidalmill"wasbuiltinBrittanyontheFrenchcoast,usingtidalenergyinsteadofmanpowertopushthemill.Withtheadvancementofscienceandtechnology,peoplebegantobuilddamsandbuildtidalpowerstations.
Francehasbuilttheworld'sfirstlarge-scaletidalpowerstationinBrittany.Thepowerstationishuge.Thedamis750meterslongandthetopofthedamisaroad.Theaveragetidalrangeis8.5meters,andthemaximumtidalrangeis13.5meters.Theannualpowergenerationcapacityis544millionkilowatt-hours.
След освобождението на Китай някои малки приливни електроцентрали бяха построени по протежение на крайбрежието. Например, DaliangTidalPowerStation в окръг Шунде, провинция Гуангдонг (144kW), HuameiTaikooTidalPowerStation в Xiamen, Fujian (220kW), ShashanTidalPowerStation (40kW) в Wenling, Zhejiang и Xiangshan Gaotang Tidal PowerStation (450kW).
3. Генериране на вълнова енергия
"Three-footwaveswithoutwind"isatrueportrayaloftheendlesssea.Thewaveshaveamazingpower.Awaveof5metershighhas10tonsofpressurepersquaremeter.Bigwavescanthrow13tonsofrockstoaheightof20meters,flip1,700tonsofrocks,andevenpushtensofthousandsoftonsofhugeshipsashore.
Thetotalenergycontainedinthewavesisamazing.Itisestimatedthattheenergycontainedinthewavesoftheearthisequivalentto90trillionkilowatt-hoursofelectricalenergy.
Utilizationstatus
Someoftheabove-mentioneddifferentformsofenergyhavebeenusedbyhumans,andsomehavebeenincludedinthedevelopmentandutilizationplan,butthedegreeofdevelopmentandutilizationofoceanenergybypeopleisstillverylow..Althoughtherearevariousdifferencesbetweenthesemarineenergyresources,theyalsohavesomecommoncharacteristics.Eachoceanenergyresourcehasaconsiderableenergyflux:tidalenergyandsalinitygradientenergyareabout2TW;waveenergyisalsoonthisorder;andoceanthermalenergyisatleasttwoordersofmagnitudelargerthanthis.Buttheseenergiesarescatteredinawidegeographicalarea,soinfacttheirenergyflowdensityisquitelow,andmostoftheseresourcesarestoredintheseaawayfromthecentralareaofelectricity.Therefore,onlyasmallpartoftheoceanenergyresourcescanbedevelopedandutilized.
1.Срещани проблеми
Therearetwomainreasonswhymanyoceanenergyresourceshavenotbeenusedsofar:First,economicbenefitsPoor,highcost.Second,sometechnicalissueshavenotyetbeenresolved.Nevertheless,manycountriesareorganizingresearchtosolvetheseproblems,whileatthesametimeformulatinggrandoceanenergyutilizationplans.Forexample,Franceplanstousetidalenergytogenerate35billionkilowatt-hoursbytheendofthiscentury,Britainplanstobuilda1millionkilowattwavepowerstation,andtheUnitedStatesplanstobuild500oceanthermalpowerstationsontheeastcoast.Fromtheperspectiveofdevelopmenttrends,oceanenergyisboundtobecomeoneoftheimportantenergysourcesforcoastalcountries,especiallydevelopedcoastalcountries.
2.Перспективи
Thereisalargeamountofrenewableoceanenergyintheworld.AccordingtoestimatesfromaUNESCOpublicationin1981,thetheoreticallyrenewabletotalofthefivetypesofoceanenergyis76.6billionkilowatts.Amongthem,thetemperaturedifferenceenergyis40billionkilowatts,thesalinitydifferenceenergyis30billionkilowatts,thetidalandwaveenergyareeach3billionkilowatts,andtheoceancurrentenergyis600millionkilowatts.However,asmentionedabove,itisdifficulttoextractalltheabove-mentionedenergy.Itisassumedthatonlystrongoceancurrents,tidesandwavescanbeused;thesalinitydifferenceintheareawithheavyrainfallisused,andtheutilizationofthetemperaturedifferenceislimitedbytheCarnotefficiencyoftheheatengine.Therefore,itisestimatedthatthetechnicallyallowableutilizationofpoweris6.4billionkilowatts,ofwhichthesalinityenergyis3billionkilowatts,thetemperaturedifferenceenergyis2billionkilowatts,thewaveenergyis1billionkilowatts,theoceancurrentenergyis300millionkilowatts,andthetidalenergyis100millionkilowatts(estimatedfigures).
Theintensityofoceanenergyislowerthanconventionalenergy.Theseawatertemperaturedifferenceissmall,andthelargetemperaturedifferencebetweentheseasurfaceandthe500-1000metersdeepwaterisonlyabout20℃;thetidalandwavewaterleveldifferenceissmall,thelargetidalrangeisonly7-10meters,andthelargewaveheightisonly3meters;tidalcurrents,oceancurrentsThespeedissmall,andthelargerflowrateisonly4to7knots.Evenso,amongrenewableenergysources,oceanenergystillhasaconsiderableenergyflowdensity.Takingwaveenergyasanexample,theaveragewavepowerpermeterofcoastlineintherichestseaareais50kilowatts,generally5to6kilowatts;thelatterisequivalenttothesolarfluxdensityof1kilowatt/m2).Anotherexampleistidalcurrentenergy.TheZhoushanIslandstidalcurrentwithamaximumvelocityof3m/shasanaveragetidalpowerof4.5kW/m2inatidalcycle.Asanaturalenergysource,oceanenergyisconstantlychanging.However,theoceanisahugeenergystoragereservoir,whichstoressolarenergyandderivedwindenergyintheformofheatandmechanicalenergyinthesea,whichisnotaseasytoloseasitisonlandandintheair.Theseatemperaturedifference,salinitydifferenceandoceancurrentarerelativelystable,24hoursadaywithoutinterruption,smallfluctuationsbetweendayandnight,andonlyslightlyseasonalchanges.Tidesandcurrentsmakeconstantperiodicchanges,whichcanaccuratelypredictspringtides,smalltides,hightides,lowtides,tidelevels,tidespeeds,anddirections.Oceanwavesarethemostunstableintheocean,withseasonalityandperiodicity,andadjacentcyclesarealsochanging.However,oceanwavesarethesumofwindwavesandswells,andswellsoriginatefromwindenergyinthevastoceanforalongtime.Theyarenotaseasytoriseandstopasthelocalsunandwindandareaffectedbylocalweather.
Theutilizationofoceanenergyisstillveryexpensive.TaketheLancetidalpowerstationinFranceasanexample.ItsunitkilowattinstalledcapacityisUS$1,500(pricein1980),whichishigherthanconventionalthermalpowerstations.However,incoastalareas(includingislands)whereenergyisseverelylacking,itisstilladvisabletouseoceanenergyasasupplementaryenergysource.
mycountry'scurrentsituation
Ingeneral,mycountry'soceanenergyresourcesareveryrich,andtheamountofdevelopmentandutilizationcanreach1billionkW.Amongthem,thetotalinstalledcapacityoftidalenergyresourcesonthecoastofmycountryis2179kW;thetheoreticalaveragepowerofwaveenergyis12.85millionkW;thetheoreticalaveragepowerof130tidalchannelsis13.94millionkW;thetotalamountofthermalenergyresourcesavailablefordevelopmentinoffshoreandadjacentseaareasTheinstalledcapacityisabout1.747billionto21.865billionkW;thetheoreticalpowerofcoastalsaltenergyresourcesisabout114millionkW;offshorewindenergyresourcesreach750millionkW.
Developmentprocess
mycountry’soceanenergydevelopmenthasahistoryofnearly40years.Sofar,8tidalpowerstationshavebeenbuilt.Sincethe1980s,Zhejiang,Fujianandotherplaceshavebeenaffectedbyseverallargeandmedium-sizedtidalpowerplants.Forthepowerstation,alargenumberofpreliminarypreparationshavebeencarriedout,suchasinspection,survey,planneddesign,andfeasibilitystudy.Inshort,mycountry'soceanpowergenerationtechnologyhasagoodfoundationandrichexperience,andthesmall-scaletidalpowergenerationtechnologyisbasicallymature,andithasthetechnicalconditionsforthedevelopmentofmedium-sizedtidalpowerstations.However,theoverallscaleandunitcapacityoftheexistingtidalpowerstationsarestillsmall,andthecostperkilowattishigherthanthatofconventionalhydropowerstations.Theconstructionofhydraulicstructuresisstillrelativelybackward,andthehydro-turbinegeneratorsetshavenotyetbeenfinalizedandstandardized.Theseareallproblemsinthedevelopmentoftidalenergyinourcountry.Thekeyproblemisthatthetechnicalproblemsofthehydro-generatorunitsofthemedium-sizedtidalpowerstationhavenotbeencompletelysolved,andthecostofthepowerstationneedstobereducedurgently.
mycountry'swavepowertechnologyresearchbeganinthe1970s,andhasbeendevelopingrapidlysincethe1980s.Microtidalpowergenerationdevicesfornavigationlightshavebecomecommercialized.Hundredsofthemhavebeenproducedincoastalwaters.Andpopularizeandapplyonlargelightboats.Theback-benttubebuoypowergenerationdevicedevelopedincooperationwithJapanhasbeenexportedtoforeigncountries,andthetechnologyisattheinternationalleadinglevel.Theshore-sidefixedwavepowerstationdevelopedonDawanshanIslandinthePearlRiverEstuary,thefirstdevicewithaninstalledcapacityof3kW,wassuccessfullytestedforpowergenerationin1990.The"EighthFive-YearPlan"scientificandtechnologicalresearchprojecthasashorewavepowerteststationwithatotalinstalledcapacityof20kWandan8kWpendulumwavepowerteststation,bothofwhichhavebeensuccessfullyconstructed.Inshort,althoughmycountry'swavepowergenerationstartedlate,ithasdevelopedrapidly.Microwavepowertechnologyhasmatured,andsmallshorewavepowertechnologyhasenteredtheworld'sadvancedranks.However,thescaleofwaveenergydevelopmentinmycountryismuchsmallerthanthatofNorwayandtheUnitedKingdom,andsmallwavepowergenerationisstillfarfrompractical.
Theresearchontidalcurrentpowergenerationbeganinthemid-1970sinternationally.TheUnitedStates,Japan,andtheUnitedKingdomaremainlyengagedintidalcurrentpowergenerationtestresearch.Sofar,thereisnoreportontheactualpowergenerationdevice.Theresearchontidalcurrentpowergenerationinmycountrybeganinthelate1970s,andtheprincipletestof8kWtidalcurrentgeneratingunitswasfirstcarriedoutintheZhoushanwaters.Inthe1980s,thevertical-shaftself-adjustingbladeturbinetidalcurrentpowergenerationdevicehasbeentestedandresearched,andthisprincipleisbeingusedfortheresearchof70kWtidalcurrenttestpowerstation.ThesiteofthestationintheZhoushanwatershasbeenselected.mycountryhasbeguntoresearchandbuildphysicalpowerstations,anditisinaleadingpositionintheworld,buttherearestillaseriesoftechnicalproblemstobesolved.
Comparedwithotherenergysources,tidalcurrentenergyhasthefollowingadvantages:strongregularityandpredictability;highpowerdensity,stableenergy,easytomanagethegenerationanddistributionofthepowergrid,anditisakindofExcellentrenewableenergy;theuseoftidalenergyisusuallyopenandwillnothaveabigimpactonthemarineenvironment.
Inthepast20years,drivenbythefossilfuelenergycrisisandthepressureofenvironmentalchanges,theoceanenergybusiness,oneofthemainrenewableenergysources,hasmadegreatprogress.Withthesupportofrelevanthigh-techsupport,Oceanenergyapplicationtechnologyisbecomingmoreandmoremature,showingabrightprospectformankindtomakefulluseofoceanenergyinthenextcentury.mycountryhasamainlandcoastlineofmorethan18,000kilometers,morethan6,960largeandsmallislands,atotalareaof6,700squarekilometers,morethan430inhabitedislands,andatotalpopulationofmorethan4.5million.Coastsandislandsarenotonlythebasesforexport-orientedeconomy,butalsotheoutpostsformarinetransportationandmarinedevelopment,andtheyplayanimportantroleinconsolidatingnationaldefenseandsafeguardingtherightsandinterestsofthemotherland.Sincethereformandopeningup,withthedevelopmentofthecoastaleconomy,thedevelopmentofislandsisimminent,andtheshortageofenergyhasseverelyrestrictedtheeconomicdevelopmentandtheimprovementofpeople'slivingstandards.ForeignbusinessmenandoverseasChinesearereluctanttoinvestduetothelackofenergyintheislands;thetroopsstationedontheislandshavedifficultyinusingelectricity,whichisnotconducivetotheconstructionofnationaldefense;especiallytheislandsfarawayfromthemainlandsuchasXishaandNansharelyonthemainlandforenergysupply.hard.Inordertoensurethesustainedandrapiddevelopmentofthecoastalandislandeconomiesandthecontinuousimprovementofpeople'slivingstandards,itisurgenttofindawaytosolvetheshortageofenergysupply.
Technologystatus
Accordingtodata,sincethe1980s,mycountryhassuccessivelybuiltabatchofsmallandmediumtidalpowerstationsinvariouscoastalareasandputthemintooperationforpowergeneration.ThelargesttidalpowerstationistheJiangxiaTidalTestPowerStationinWenlingCity,ZhejiangProvince,whichwasbuiltinMay1980.Itisalsooneofthelargertwo-waytidalpowerstationsbuiltintheworld.Thetotalstoragecapacityis4.9millioncubicmeters,andtheeffectivestoragecapacityforpowergenerationis2.7millioncubicmeters.Themaximumtidalrangehereis8.39metersandtheaveragetidalrangeis5.08meters;thepowerofthepowerstationis3,200kilowatts.ItisunderstoodthattheJiangxiaPowerStationcangenerateelectricityfor14-15hoursadayandnight,whichis30%-40%morethantheunidirectionaltidalpowerstation.TheJiangxiaPowerStationcanprovide10billionwatts/hourofelectricityfortheWenlingandHuangyanpowergridseveryyear.
Inadditiontotidalenergy,thefocusisonthedevelopmentofwaveenergyandseawaterthermalenergy.Statisticsshowthatoceanwavesgenerate200,000kilowattsofenergyonthesurfaceof1squarekilometerpersecond.Theavailablewavesintheworld’soceansareabout2.7to3billionkilowatts,whilethereservesofwavesinmycountry’scoastalwatersareabout150million.Kilowatts,whichcanbeexploitedandutilizedisabout30-35millionkilowatts.Somedevelopedcountrieshavebeguntobuildsmallwavepowerstations.
Thethermalenergyofseawateristhattheseawaterontheseasurfaceisheatedbythesun,anditisdecompressedinavacuumpumptoturntheseawaterintosteam,whichthendrivesasteamturbinetogenerateelectricity.Atthesametime,thesteamisbroughtinagainandrecoveredasfreshwateraftercooling.Thesetwotechnologiesareunderresearchanddevelopmentinmycountry.
Existingpowerstation
OnMay4,1980,thefirstunitoftheJiangxiaTidalPowerStationinWenling,ZhejiangProvince,wasconnectedtothegridforpowergeneration,unveilingthelarge-scaleconstructionoftidalpowerstationsinChina.Theprologue.Thepowerstationisequippedwith6500-kilowatthydroelectricgeneratingunitswithatotalinstalledcapacityof3,000kilowatts.Thetidalbarrageis670meterslongandtheeffectivereservoircapacityis2.7millioncubicmeters.Itisamoderntidalpowerstationofalargescale.ItnotonlymakesduecontributionstosolvingtheenergyshortageinZhejiang,butalsohastheabilitytocompeteeconomically.TheunitcostoftheJiangxiatidalpowerstationis2500yuanperkilowatt,whichisequivalenttothecostofasmallhydropowerstation.Thesmall40-kilowatttidalpowerstationinShashan,Zhejiang,hasbeeningoodconditionsinceitscompletionin1959,withaninvestmentof40,000yuanandanincomeofmorethan350,000yuan.TheHaishanTidalPowerStationhasaninstalledcapacityof150kilowatts,anannualpowergenerationof290,000kilowatt-hours,andanincomeof20,000yuan.Italsobreedscockles,fishandshrimpandmakesbrickswithanannualincomeof200,000yuan.
Therearethreeformsoftidalpowergeneration:oneissingle-storageunidirectionalpowergeneration.Itistobuilddams,powerhousesandsluicesinthebay(orestuary)toseparatethebay(orestuary)fromtheopensea.Thesluiceisopenedathightide,andthetidefillsthereservoir.Atlowtide,thedifferencebetweenthewaterlevelinsideandoutsidethereservoirisusedtoformastrongThepowerfulfaucetimpactsthehydro-generatorunittogenerateelectricity.Thismethodcanonlygenerateelectricityatlowtide,soitiscalledsingle-storageone-waypowergeneration.Thesecondtypeissingle-storagetwo-waypowergeneration,whichalsoonlybuildsareservoir,adoptscleverhydraulicdesignoradoptstwo-wayhydroelectricgeneratorsets,sothatthepowerstationcangenerateelectricitywhenthetiderisesandfalls.However,neitherofthesetwopowergenerationmethodscangeneratepowerwhenthetideislow.Thethirdtypeisdual-storagetwo-waypowergeneration.Itistobuildtworeservoirsinthebaywithfavorableconditions.Duringthehightideandlowtide,thewaterlevelofthetworeservoirsalwaysmaintainsacertaindrop.Thewaterturbinegeneratorisinstalledbetweenthetworeservoirstocontinuouslygenerateelectricity.
Tidalpowergenerationhasmanyadvantages.Forexample,thetidescomeandgoregularlyandarenotaffectedbyfloodsorlowwaters;takingestuariesorbaysasnaturalreservoirswillnotfloodalotofland;theydonotpollutetheenvironment;theydonotconsumefuel,etc.However,tidalpowerstationsalsohavedisadvantagessuchasarduousengineering,highcost,andthecorrosiveeffectofseawateronunderwaterequipment.However,thecomprehensiveeconomiccomparisonshowsthatthecostoftidalpowergenerationislowerthanthatofthermalpower.