能源需求说课讲解

能源需求第一页，共54页。第一节基本概念1、能源需求2、能源需求总量与能源需求结构(jiégòu)3、能源强度4、能源需求弹性第二页，共54页。一、能源需求能源需求是指在各种可能的价格下，消费者对能源资源(zīyuán)愿意并且能够购买的数量。能源需求是引致需求（deriveddemand），能源的价值是由其提供服务的能力决定。第三页，共54页。Inparticular,whencombinedwithenergy-usingcapital,energyfacilitatestheprovisionofgoodsandservicesinindustryandinthehousehold.Therefore,energyconsumptionattheindividual,householdand/orfirmlevelistheresultofasetofsimultaneousdecisionsinvolvingthequantityandtypeofcapitalequipmenttopurchase–wherecapitaltypeisdifferentiatedbytechnologicalcharacteristicssuchasefficiencyandtypeoffuelinput–andtherateofcapitalutilization.第四页，共54页。Today’smoderneconomythrivesontheconsumptionoffossilfuels.AccordingtotheUSEnergyInformationAdministration,globalprimaryenergydemandincreasedatanaverageannualrateof2.0percentfrom1980to2005,andthisdemandhasbeenmetprimarilybyfossilfuels.第五页，共54页。In2005,petroleumcomprised36.6percentoftotalenergyuse，followedbycoalat26.5percent,andnaturalgasat23.3percentDespitethisconjectureoffossilfuel’sdominance,thecompositionofenergydemandhasnotbeenconstantovertime,norwillitbeaswemoveforward.第六页，共54页。Today’stechnologiesandcapitalstocksaretunedtoconvertingfossilfuels,ratherthansomeotherenergysource,intosomeusefulenergyservice,butyesterday’stechnologyandverylikelytomorrow’stechnologieswillbedifferent.第七页，共54页。二、能源需求总量与能源需求结构(jiégòu)1、能源需求总量是指研究的一定范围内各种能源需求量之和，如一次能源需求量、化石(huàshí)能源需求量等。能源需求量通常是指一次能源需求量。2、Energybalancetables（能源平衡表）areusefuldatareportingtools.Theyallowtheresearchertotrackthetotalenergyrequiredtofacilitatefinalconsumptionbysectorandfueltype第八页，共54页。EnergybalancetablesareameansofaccountingfortheconversionofprimaryenergyforfinalconsumptionFigure1illustratesthegeneralflowofenergybalancetables第九页，共54页。第十页，共54页。一国的能源需求总量（Totalprimaryenergyrequirement，TPER）是由终端能源需求量（totalfinalconsumption，TFC）、能源加工转换损失量和损失量三部分构成。终端能源需求量，按照OECD和IEA的定义，是指终端用能设备入口(rùkǒu)得到的能源。第十一页，共54页。能源加工转换损失量。是指一定时期内全国投入加工转换的各种能源数量之和与产出各种能源产品之后的差额，是观察(guānchá)能源在加工转换过程中损失量变化的指标。能源损失量，是指一定时期内能源在输送、分配、储存过程中发生的损失和由客观原因总成的各种损失量。第十二页，共54页。因此终端能源需求量是指一次能源消费量减去能源加工、转换和储运这三个环节的损失和能源工业所用能源后的能耗量。其中，中间环节损失包括选煤和型煤加工损失、炼油损失、油气田损失、发电、电厂供热、炼焦、制气损失、输电损失、煤炭储运损失、油气运输损失。在中国能源平衡表统计(tǒngjì)中，只扣除选煤、炼焦、油田、炼油、输配电损失，未扣除发电损失和能源工业所用能源。因此计算出来的终端能源需求量远高于国际通行准则计算得出的数量。第十三页，共54页。TPERisgreaterthanTFCduetotheenergyexpendedintheconversion,transmissionanddistributionactivitiesthedifferencebetweenTPERandTFC,referredtoasconversionanddistributionlosses,canvaryacrosscountriesdependinguponanumberoffactors,suchaswhichfuelsareusedandhowefficienttheconversionprocessesare.第十四页，共54页。能源需求结构(jiégòu)：是指能源需求总量中各种能源品种所占的比例。（P15，世界主要国家能源消费结构(jiégòu)）一国的能源需求结构(jiégòu)主要受制于该国的能源资源禀赋和能源技术。第十五页，共54页。三、能源(néngyuán)强度能源强度又称单位产值能耗或能源密集度，是指一段时间内，某一经济行为体单位产值消耗的能源量，通常以吨（或公斤）油当量（煤当量）/美元（或其他货币单位）来表示。一个国家或地区的能源强度，通常以单位国内生产总值耗能量来表示。能源强度是反映经济对能源依赖(yīlài)程度的一个重要指标，越高，反映依赖(yīlài)程度越高。第十六页，共54页。能源强度反映经济行为主体利用能源效率(xiàolǜ)的情况，与能源强度近似的反映能源技术效率(xiàolǜ)的指标：加工转换效率(xiàolǜ)、储运效率(xiàolǜ)和终端利用效率(xiàolǜ)，这些指标是指在使用能源的活动中所得到的有效能与实际输入的能源量之比，一般用百分比表示。能源效率(xiàolǜ):能源开发、加工、转换、利用等各个过程的效率(xiàolǜ)。减少提供同等能源服务的能源投入。它更强调通过技术进步实现节能。能源强度的计算只需能源需求量和当年的GDP，数据比较容易获得，因而在实际中得到广泛的运用。第十七页，共54页。能源强度指标反映了由技术水平、发展(fāzhǎn)阶段、经济结构、能源需求结构等多方面因素形成的能源需求水平和经济产出的比例关系，而非单纯技术水平决定的能源利用效率。在运用该指标对不同国家能源效率进行比较时，要考虑到汇率因素的影响。第十八页，共54页。

TrendsinenergyintensityintheUS(1880–2005)

第十九页，共54页。第二十页，共54页。econometricanalysistoshowthattheenergyintensityofaneconomyresemblesaninvertedU-shapeacrossincreasinglevelsofpercapitaincome.Thisarisesfromstructuralandtechnologicalchange.Itisimportanttonoteherethatdecliningenergyintensitydoesnotimplythatenergydemanddeclines,onlythatenergydemandgrowsmoreslowlythanoutput.第二十一页，共54页。1、经济(jīngjì)结构对能源强度的影响Toillustratehowstructuralchangecanleadtochangesinenergyintensity,considerathree-sectoreconomy(denotedassectorsA,IandS).Totalenergyconsumptionisgivenasthesumofenergyuseacrossallsectors,第二十二页，共54页。TheenergyintensityineachsectoricanbegivenaswhereYiistheoutputofsectori.TotaloutputisgivenasTotalenergyintensitycanbewrittenas:(1)第二十三页，共54页。whereisthesectorishareoftotaloutput.Thus,totalenergyintensityisashareweightedsumofenergyintensityofeachsector.Also,bydefinitionAssumethattheenergyintensityofeachsectorcanbeorderedsuchthat:第二十四页，共54页。ItfollowsthatifsectorIgrowsfasterthansectorA,holdingtheoutputshareofsectorSconstant,energyintensitywillincrease.Toseethis,wecantakethederivativeofequation(1)withrespecttotheoutputshareofindustry:(2)第二十五页，共54页。Weknow(2)ispositivebecause:

Thus,theimpactonenergyintensityoftheaggregateshifttoindustryispositive.Wecanalsoshow,inasimilarmanner,thatgrowthinthelessenergy-intensivesectorsresultsindecliningenergyintensity.第二十六页，共54页。2、技术变化对能源(néngyuán)强度的影响Technologicalprogresseffectivelylowersthepeakenergyintensityofaneconomy.Thus,foragiveneconomy,thelaterintimeitdevelopstheloweritsenergyrequirementswillbe。Thisisbecausethediffusionofnewertechnologiesandtheeconomic/environmentallessonslearnedintheindustrializedworldcontributetoloweringthemaximumenergyintensityofdevelopingnations.第二十七页，共54页。Ingeneral,becauseenergyconsumptiondependsontheenergyefficiencyandutilizationrateofinstalledcapitalandthescaleoftheoperation,wecanwritethefollowingexpressionforenergyuse:（3）whereEdenotesenergyuse,udenotescapacityutilizationofcapital,denotestheenergyefficiencyofcapital,andKdenotesthecapitalstock第二十八页，共54页。Combiningequations(1)and(3)yieldsanexpressionthatcanbeusefulinunderstandingtheinfluenceoftechnology:（4）Fromequation(4)wecanseethatanincreaseinenergyefficiencyinanysectori,forinstancethroughtheadoptionofanewtechnology,willleadtoadeclineintheenergyintensityofsectori,andhenceoverallenergyintensity.第二十九页，共54页。

Thisisapparentbysimplydifferentiatingequation(4)withrespecttoenergyefficiencyinsectori:

Notably,theimpactofthetechnologicalchangewillhavethegreatestimpactifitoccursinthesectorwiththelargestshareoftotaloutput.Thishasimplicationsforthedesignofanypolicydirectedatloweringenergyintensitythroughraisingenergyefficiency.第三十页，共54页。3、能源(néngyuán)强度与能源(néngyuán)效率Considertwocountrieswiththesamelevelofpercapitaincome,countryAandcountryB,andassume(E/Y)A.(E/Y)B.SinceenergyintensityishigherincountryA,itisacommonmistaketoassumethatenergyefficiencyishigherincountryB.Whilethismayindeedbetrue,itdoesnotnecessarilyfollow.Inparticular,theeconomicstructureofcountriesAandBmaybeverydifferent.Forexample,countryAmayspecializeintheproductionofoilandgasresourcesorsomeindustrialcommoditysuchassteel.Theseactivitiesarebynatureveryenergyintensive.CountryB,bycontrast,mayspecializeinwineproductionorglobalfinancialservices,neitherofwhichisveryenergyintensivebycomparison.Ifthesetwocountriesengageintradewitheachother,itispossiblethatthelawofcomparativeadvantagehasyieldedthemostefficientallocationofresourcesacrossbothcountries.Eachnation,therefore,maybeemployingstate-of-the-arttechnologiesthatmaximizeenergyefficiency.But,energyintensitywillnotrevealthisstructuraldifference.第三十一页，共54页。Infact,ifcountryAbeganproducingthegoodsandservicescurrentlyproducedincountryB,andcountryBbeganproducingthegoodsandservicescurrentlyproducedincountryA,theendresultwouldlikelybelowereconomicefficiency,andperhapslowerenergyefficiency.Thus,itisimportanttoaccountforthestructuraldifferencesacrosscountrieswhencomparingenergyefficiencyattheaggregatelevel.第三十二页，共54页。四、能源需求弹性(tánxìng)Therearealargenumberofempiricalstudiesthathaveestimatedtheincomeelasticityandpriceelasticityofenergydemand.Thereisagreatdealofinterestintheseelasticitiesbecausetheyarevitalwhenforecastingenergydemand.第三十三页，共54页。1、能源需求收入(shōurù)弹性（incomeelasticityofenergydemand）Theincomeelasticityofenergydemandisdefinedasthepercentagechangeinenergydemandresultingfroma1percentchangeinincome,holdingallelseconstant:第三十四页，共54页。Agoodportionoftheempiricalliteraturehadlongreportedtheincomeelasticityofenergydemandtobeclosetoone.However,severalrecentpapershaveindicatedthatthismaybegreatlyoverstatedforindustrializedcountries。第三十五页，共54页。2、能源需求价格(jiàgé)弹性own-priceelasticityofenergydemandissimilarlydefined,beingthepercentagechangeinenergydemandgivena1percentchangeinthepriceofenergyholdingallelseconstant:Notethat‘own’priceisusedheretoindicatethat‘cross’-priceelasticitiesarealsooftenestimated.第三十六页，共54页。Theown-priceelasticityisoftenusedasanindicatoroftheimpactofvariouspoliciesaimedatconservation,suchasenergytaxesorsubsidies.Forexample,itispossibletoapproximatethereductionincarbonemissionsifanaccurateestimateofpriceelasticityisinhand–agiventaxwillinfluencesomereductioninenergydemand,which,inturn,willcauseemissionstodecline.Knowingthepriceelasticity,therefore,canallowforaneducated,objectiveassessmentofthesizeofthetaxtobeinstitutedforadesiredreductioninemissions.第三十七页，共54页。Ingeneral,incomeandpriceelasticitiesofenergydemandaretherulesofthumbthathelpdirectenergypolicy.Unfortunately,ascanbeseeninareviewoftheeconomicliteratureonthematter,thereisnoconsensusregardingtheappropriatevalueofincomeand/orpriceelasticity.第三十八页，共54页。3、弹性(tánxìng)的计算从弹性的定义来看，要计算弹性需要准确知道需求量随价格(jiàgé)或收入变化的具体数量关系，然而现实中，很难获得相关变量确切的数量关系，所以有关能源各类弹性的计算多数是通过建模方法近似获取。第三十九页，共54页。五、Units,ConversionFactorsandAggregationofEnergyFlowsvariousunitsofmeasurementareusedinenergycommodityaccountingForexample,coalispresentedinthousandtonnes(万吨),gasandelectricityinGWh（十亿瓦时，gigawatthour）,andsoon。第四十页，共54页。Theconversionfromoneunittoanotherisacommonfeaturewhileworkingwithenergydata.Therefore,itisimportanttohavesomefamiliaritywiththeconversionfactors.SomecommonlyusedfactorsforconversionofmassandvolumearepresentedinTable2.(seeIEA(2004)andIPCC(2006)formoredetailedconversiontables).第四十一页，共54页。Table2Someconversion

factors第四十二页，共54页。Naturalgasdataisgenerallyreportedusingboththemetricsystem（公制(gōngzhì)）andtheimperialsystem（英制）。Incommonindustryandbusinesstransactions,boththesystemsarewidelyusedandinsomecases,theunitsusedmaybenon-standardaswell.Table3indicatessomeconversionfactorsspecifictogas.第四十三页，共54页。Table3Someconversionfactorsfornaturalgas第四十四页，共54页。Similarly,heatingvaluesoffuelsvaryanditisimportanttohaveanunderstandingoftheheatcontentofdifferenttypesoffuels.Table4givessomerepresentativevaluesforcommonlyusedfossilfuels.第四十五页，共54页。Table4GrossCalorificvaluesofdifferentenergies第四十六页，共54页。Energyismeasuredonthebasisoftheheatwhichafuelcanmakeavailable.Measurementonthebasisoftotalenergyavailabilityiscal