Edmund Storms wrote:
When these people claim to get 250 miles/gal using a modified Prius, what they really mean is that they get 45 miles/gal plus 205 extra miles because they charge the batteries from the electric grid. This is much different from claiming that the Prius can be made more efficient just by adding extra batteries.
It is far more efficient, because it takes much less fuel to generate electricity and charge electric car than to use the Prius onboard generator. In other words, central generating plants are much more fuel efficient than the Prius generator. (Modern ones are -- not the old ones.)
If your modified plug-in Prius is powered by a combination of the on-board ICE plus a gas-fired central generator, and the distance you commute is short, so that the onboard ICE is seldom needed, efficiency will be at least 50% higher. If you live in Seattle, Washington and your local electricity comes from hydroelectricity or wind, your fuel efficiency is effectively infinite.
Using this logic, a pure electric car would get an infinite number of miles/gal.
Yes, powered by wind, it would. To be precise, it would be powered by nuclear fusion in the Sun, which produces a very large number of miles per kg of hydrogen.
Consequently, the quoted miles/gal actually has no meaning.
I think this quoted ratio is quite meaningful. It indicates approximately how many million barrels of gasoline the US would save if everyone drove a plug-in hybrid automobile. Since the average car now gets 20 miles per gallon, this figure indicates that we would reduce consumption of petroleum (oil) by a factor of 10 or more, which is probably correct. Of course we would increase consumption of coal and uranium somewhat, to compensate, but the overall caloric value of the fuel consumed would also fall by a large factor, and the amount of CO2 and pollution generated would also decline dramatically.
- Jed
