>I think it can be greener in several ways. First it allows you to move the energy generation to less dense areas where pollution is not as much of a problem (away from high density metro areas and traffic area's). Second it allows you to generate more efficiently (I assure you a couple of large plants maintained by professionals is cleaner than millions of small powerplants ignored by their owners.) Third it lets you be interchangable on your fuel. If you have solar or wind, use that but you can still use the current crop of oil/gas base fuels also and change when appropriate without requiring millions of people to convert.

Additionally, we'd need to compare the energy efficiency of an electric engine versus that of an ICE. The latter, AFAIK, doesn't go much over 20% at best, except in (surprise?) hybrid engines, where it's run at its peak efficiency of up to 37% - see http://en.wikipedia.org/wiki/Internal_combustion#Engine_Efficiency for source. OTOH, http://en.wikipedia.org/wiki/Electric_motor says "Brushless motors are typically 85-90% efficient, whereas DC motors with brushgear are typically 75-80% efficient".

IOW, the same amount of mineral oils yields about 3 times more energy if used to generate electricty to run an electrical motors than when used to run an internal combustion engine in a car. Note that ICE actually performs worse when cold, when it's not well tuned, when it runs too slow or too fast - which is your typical drive out, stop at the light, start, stop, start commute.