Quote:
Originally Posted by NeilBlanchard
Hi Matt,
I've been looking around that site, and it is a bit dense -- lots of info, but not very easy to find specific answers. Do you have a direct link to how much energy is embedded in gasoline?
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Neil,
This PDF seems to show that gasoline refining is 87.7% efficient and 4.3% of the energy used is purchased electricity.
http://www.transportation.anl.gov/mo...ries-03-08.pdf
So I'm not sure you can just say that 7.5 kWhr went into the gasoline that could have been used for charging an EV. I think you'd have to use the 4.3% that was purchased. If the balanced was burned fossil fuels, you'd still have to convert that to electricity, so apply a 1/3 multiplier to that (to convert it to electricity instead of burning for refining).
So, 100 - 87.7 = 12.3% used for refining.
12.3% X 4.3% = 0.529% was purchased electricity.
33.4 kWhr/gal X .529% = 176.7 Whr of purchased electricity "embedded" in each gallon.
100 - 4.3 = 95.7% of energy used for refining was from "petroleum" sources.
95.7% X 12.3% = 11.77% of the energy in each gallon was "embedded" burned fossil fuels.
33.4 kWhr/gal X 11.77% = 3.93 kWhr of "embedded" refining energy from fossil fuels. But we cannot use that as electricity without burning it in an engine, so divide by 3. (Even so, I'm not sure you could just burn it in an engine to make electricity without refining it first).
3.93/3 = 1.31 kWhr that we would have if we burned the fossil fuel to make electricity instead of refining the gasoline.
1,310 + 176.7 =
1,487 Whrs of electricity we could have had to charge the EV instead of it being used to make the gasoline, about 1/5th of Nissan's number.
OK, what's wrong with my math?
