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Old 04-27-2009, 06:22 PM   #21 (permalink)
aerohead
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Quote:
Originally Posted by dcb View Post
Who in their right mind would evaluate the energy chain of an EV (or a biodiesel) using such a phrase?!? Try again.
I apologize,as I'm late to the party.I have some articles at home,from the 1990s,on EVs and alternate fuel vehicles and they were strong in emphasizing to the reader,the entire energy thermal efficiency pathway,from wellhead,mine,hydro dam,PV array,nuke,wind turbine,etc.,so we didn't lose sight of the entire energy balance.

At that date,they were talking about electric generation efficiencies of maybe 32% tops,then 7% loss in transmission lines to the household,the battery charger might have somewhere in the 85% efficiency.The battery might be around 80%,the propulsion motor might be 95%,but the controller would eat some of the battery power.

From the power station,to the drive wheel of the EV,the total thermal,or energy efficiency of the EV was less than stellar.

In 1988,the US EPA allowed car makers a CAFE rating of EVs,from200-400 mpg,for figuring fleet mpg on a sales-weighted basis.That doesn't mean they can do it.The GM Sunraycer was rated by Dr.Paul MacCready at 400-mpg as a gasoline car.We're talking curb weight under 400-pounds,maybe 4 square feet of frontal area,and Cd0.12.I agree with Ernie that we need to be firmly grounded in good science when we're throwing quanta around.

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