Originally Posted by David Bierbaum

The problem with electric cars is that electricity isn't a fuel; it's a storage medium. This means your car is fueled by whatever fuels your power grid, which is most likely coal, natural gas, nuclear, or hydroelectric power (in order of "green-ness," from low to high).

Of course, even bicycling fuel (food) isn't particularly green, with all the petrochemical costs involved in farming, processing, and transporting all this stuff... And the human body is not nearly as efficient at converting fuel to work as our modern mechanical contrivances. If we are ever phased out of production by our robot overlords, it will doubtless be a far greener planet!