> So the MPG rating is based on the power plant emissions per mile's worth of energy consumed by the vehicle and comparing that with gasoline emissions? This s

> So the MPG rating is based on the power plant emissions per mile's worth of energy consumed by the vehicle and comparing that with gasoline emissions? This sentence appears to be very, very confused. It's not based on emissions at all. It's not energy per mile. And it's not MPG, but MPGe. "MPGe" is "Miles Per Gasoline Equivalent", and is not MPG. This is an odd historical measure of engine efficiency which stems from early attempts to shoehorn natural gas vehicles into CAFE standards. For purposes here, I believe what the EPA did is take the energy contained in one gallon of gasoline (33.7 kW-hr) and computed how many miles an electric vehicle would go when consuming that amount of energy put into its battery. It's useful for comparing electric vehicles to electric vehicles, but not useful for comparing across different kinds of propulsion. What you probably want is Miles per Dollar. This would have to be computed both for your gas car and your electric car, and has to be computed based on the cost of gasoline in your area, the efficiency of your two cars, and the cost of night electricity (most utilities have night-consumption plans for electric vehicles). But my understanding is: at present most people see their electric vehicles costing about 1/3 per mile of a gas vehicle. That doesn't take into consideration the generally lower costs of maintenance as well (gas engines are complex).