In his blog, my friend Paul Scott has written a marvelous post on calculating the pollution caused by charging electric vehicles with energy from fossil-fuels. He makes several astute comments and suggestions regarding how the EPA should, in fact, make this determination fairly.
He asks such questions as:
How do you compute the amount of pollution generated from coal and natural gas? Do you take the national average for a kilowatt hour of energy? I’ve read it’s just over one pound of CO2 per kWh. Or do you allow for regional variation? California is among the best in terms of per capita efficiency and a low CO2 grid, and we’ll be the first state to mass adopt EVs. Oregon and Washington have an even cleaner grid and will match CA in per capita EV ownership. Seems only fair to allow for our cleaner grid in the calculations.
In my estimation, a far bigger factor here is that the vast majority of the energy used to charge EVs comes off-peak, where it would largely be wasted (dumped back to ground) anyway. Therefore, even EVs powered by the dirtiest of coal-fired power plants represent very little additional pollution. We could put an estimated 90 million EV on the road this afternoon without the need for a single additional power plant — coal, nuclear, or whatever. Thus this issue, I believe, is largely moot.
But don’t expect the EPA to grasp this point too quickly. These are the same people who are still trying to determine the MPG ratings for a plug-hybrid like the Chevy Volt. Apparently, the fact that this is number that has no possible definition (it could be 50, 500, 5,000 or 50,000 depending on how the car is driven) does not deter them from spending many man-years studying and debating the issue. It makes just as much sense to argue about the number of angels that can dance on the head of a pin.
In any case, I applaud Paul for his incisive and fair-minded article, and I encourage readers to check it out here.