Neil,
Even accounting for the inputs of refining and distribution, I arrived at 16KWh = 1gal in terms of CO2. Coal is dirty stuff, as you're breaking only C-C bonds and forming only CO2. HC's are better because you're breaking mostly C-H bonds, and your primary waste product (dihydrogen monoxide) is a very short lived GHG.
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Originally Posted by NeilBlanchard
And 300Wh/mile is a fairly inefficient EV -- 150 to 200Wh/mile (or even lower) is possible. And even our low efficiency generation plants are much more efficient than are ICE's. So, with oil the carbon footprint is very complex and things add up quickly. With electricity, even right now, there is much lower carbon used per BTU than for gasoline -- and it is possible to generate electricity from renewable energy sources, so it can be virtually carbon free.
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22mpg is an extremely inefficient gas-burning vehicle, yet that's what people buy. 300Wh/mi at the wall is more like 250Wh/mi at the battery, which is pretty ordinary. Give it a few months, and we'll see what the EPA says the Leaf and Volt can do with a KWh.
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So, shutting down refineries doesn't power the EV's for as many miles, but those miles are essentially "free" because that carbon is not used to refine the gasoline. If you replace the total miles with more electricity, then the total carbon is lower because of the higher efficiencies of generators and electric motors vs the ICE's you would be replacing. In other words, if you put the energy into electricity, you get more work and/or use less carbon than you do with petroleum.
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This is terribly incorrect. Total carbon is comparable because electricty is far more carbon-intense per MJ than gasoline. Unsurprising if you understand that on the other end of the power lines is a heat engine that, sadly, is probably about 35% efficient. We can do better.