That figure would be relevant if we got 60% of our electricity from petroleum. It might even be worth mentioning if we got 30% of our electricity from petroleum. You could even be excused for bringing it up if we got 10% of our electricity from petroleum.
However, it is absolutely irrelevant since we only get 1% of our electricity from petroleum.
I think I'll just trust KBB’s numbers instead.
12 kWH for 45 miles means 12,000 divided by 150 square-meter-hours. Divided by 45 and you get a little under 2 square meter hours per mile. (IOW 2 square meters of solar panels for one hour for each mile driven).
If you want to use the power grid mix instead then you must use retail prices because those represent the costs (my electric company and all their suppliers are non-profit). That means $1.68 for those 45 miles in my case in Virginia. With $3 gas that is 80 mpg equivalent (for the Volt).
In the 80 mpg equivalent I did not count taxes which are 36 cents including federal and Virginia taxes.