Today's NyTimes piece on the estimated milage of the Chevy Volt has me thinking about emissions. Specifically, how much are we saving by moving from internal combustion to electric with centralized (generally, coal) energy production. Not finding a decent answer online, I decided on a back-of-the-envolope approach based on the bits I could find.
As it turns out, a typical coal fired electric plant producing 3.5 billion kilowatt hours (kWh) of energy does so at a cost of 7.4 billion pounds of carbon dioxide, resulting in an cost of 2.11 pounds of CO2 per 1 kWh of output.
The EPA favored measure of an all-electric car's performance is the total energy required to travel 100 miles. For the electric version of the Mini, this ends up being 33 kWh, resulting in a cost of 0.33 kWh per mile. Assuming that your house is fed by coal (which is true for about 43% of you), this gives about 0.70 pounds of CO2 per mile.
Because I'm on a Yaris kick, we'll use it as our point of comparison. The Yaris hits an (EPA rated) 29 MPG in the city. According to my favorite federal government, a gallon of gas yields about 20 pounds of carbon dioxide. That breaks to about 0.69 pounds of CO2 per mile.
Perhaps it's time to make an offering to the clean coal gods.