I tried a calculation for an electric car, and was going to adjust the wh/km consumption but was told: "Electric vehicles don't consume fuel." I wish that were true :)
I have a friend who works for the local power company. He told me that at off peak times, our power is almost entirely green. However, at peak times, they use dirty natural gas or coal peaker plants. Even though I don't have time-of-use metered power, I make sure to always charge in the middle of the night for this reason.