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Energy Systems and Technologies for the Coming Century ...

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In addition energy consumption E <strong>and</strong> service dem<strong>and</strong> S (vehicle km driven) areanalyzed by means of econometric approaches.To analyze <strong>the</strong> impact of fuel intensity <strong>and</strong> prices on energy consumption, we start with asimple estimation of total energy consumption. We apply <strong>the</strong> conventional approachwhere energy consumption depends on price <strong>and</strong> income assuming symmetric priceelasticities:ln Et= C +α ln Pt+ β lnYt- model 1 (2)ln Et= C + α ln P + β lnY+ γ ln FI - model 2 (3)ttwhere:C…………InterceptEt……….. <strong>Energy</strong> dem<strong>and</strong> in year tPt…..……. Real energy price (calculated by means of weighted fuel prices)Yt…………Real private final consumption expenditures as a proxy <strong>for</strong> incomeAdditionally to estimating energy consumption we conduct an econometric estimate ofservice S (vkm driven).The level of service dem<strong>and</strong> S 1 of e.g. a household with respect to km driven depends onavailable income Y <strong>and</strong> <strong>the</strong> price of energy service Ps:S =f ( P , Y)SWe estimate <strong>the</strong> impacts on vkm driven by using a cointegration approach:(4)ln S lntt= C +α ln PS+ β Yt- model 3 (5)where:C…………InterceptSt……….. .Dem<strong>and</strong> <strong>for</strong> service, vehicle km driven in year t in a countryPSt………. Weighted average price of service vkm driven (calculated by means ofweighted fuel prices)Yt…………Real private final consumption expendituresεt …………Residual (error term)The most interesting numbers of this analysis are <strong>the</strong> service price elasticities because<strong>the</strong>y contain in<strong>for</strong>mation <strong>for</strong> both - price <strong>and</strong> efficiency impact.The results of cointegration are shown in Tables 1A <strong>and</strong> 1B.1 It is important to note, that "energy service“ <strong>for</strong> cars is not just distance driven. Ra<strong>the</strong>r it is kg-kmdefine or even kW-km, <strong>and</strong> efficiency is energy use/kg-km or energy use/kW-km. By <strong>the</strong>semeasures, efficiency increased enormously fed mostly by increasing weight <strong>and</strong> power <strong>and</strong> notsimply by reducing fuel consumption. Thus, a large part of <strong>the</strong> increase in energy efficiency is nottranslated into a decrease of FI.Risø International <strong>Energy</strong> Conference 2011 Proceedings Page 314

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