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Phil,
There's room for debate on whether equivalent energy is a good basis for judging the merit of using electricity vs. burning gas.
There's less room for debate on what the energy equivalence conversion factor is, when the full life cycle of both energy sources are considered: around 13.4KWh/gal. From a CO2 perspective, it's 15.1 KWh/gal on US grid-average electricity.
According to Wikipedia, "The D.O.E. reports that the lumped average efficiency of electrical production and transmission in the United States, eelectricity, is 0.303 while the efficiency of refining and distributing petroleum, egasoline, is 0.830."
So remember to apply a 17% penalty to gasoline, based on the energy cost of refining and transporting it.
I've done a little math on the merit of grid-charging my 12V and traction batteries. Using US grid average power, electric comes out only slightly ahead, from a resource depletion or CO2 perspective.
But it's a complicated subject, and kilowatt-hours can not be made "equivalent" to a gallon of gas.
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