Quote:
Originally Posted by NachtRitter
The WTW discussion is interesting, but does not / cannot address the question of mpg equivelance adequately. Once the gasoline is in my tank, the mpg value doesn't change as a result of the efficiency of the refinement process. But that is what mpg measures. Nor do the electrons in the battery cause the EV to go further if they were generated by wind versus by coal or gasoline. There is simply too much variance in the 'WTP' (well to pump, or 'well' to plug) to come up with a dependable number.
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I completely agree....
I think the complaint from the OP is rooted in that mpg is a poor metric for comparison. Potentially, but that all depends on the information one is trying to convey. MPG is understood by a VERY large group of non-experts - the most important group. If everyone could tell the difference between the Brayton and Rankine cycle, we probably would never be expressing units in MPG to begin with
Off topic, but there's been quite a few wild assumptions in this thread.... For one, the assumption of 100% coal power... I see the locations of many members, and they're not all in one place. As the grid is one large connected system, power generation efficiency should be the composite efficiency of all power sources weighted by dependence.
I live near a natural gas fired plant that allegedly uses an ultra critical turbine design - that sort of plant can get damn near 50% efficient with reheat phases and proper cooling towers (it has the stereotypical "nuclear" natural draft design - everyone thinks it's nuclear, it's not). For me to get that sort of well to wheel efficiency while someone else gets something different would be unfair
EIA - Electricity Data, Electric Power Capacity and Fuel Use, Electric Surveys and Analysis
Someone else can finish that analysis
I feel it would be interesting, but fruitless as it conveys an apparently mystic number understood only by experts.