[MetroMPG]

Ah, now I see what you're getting at. You're opening that can of worms.

EPA doesn't use power plant or efficiency of transmission to determine MPG equivalent of electrics. It uses power usage from the wall (which factors in charger in/efficiency).

If we're going to force electrics to factor in power plant to wheels, then to be fair we must also change the way we measure fossil/liquid fueled vehicles, ie. factor in energy use in refining and/or transportation of the fuel to the pump.

I think it's best to stick with the way the EPA does it.