The New York Times is running an interesting article called “The High Cost of Cheap Gas and Vice Versa.” The author calculates the current average cost of driving at 15 cents a mile, up from 6.6 cents in 1998, and down from 20.1 cents in 1980 (in 2006 dollars). He also puts up a cost-per-mile calculator, in case your math skills have deteriorated since you last took the SAT.

My colleague JP Ross tells me that a Toyota Prius in electric-only mode uses .26 kWh to go a mile. If you are filling up with peak electricity rates, say 12 cents kWh, that’s 3 cents a mile. Many utilities have nighttime off-peak rates way lower — at 5 cents kWh, that’s around a penny a mile.

In places where the wind blows at night, you could be filling up as you sleep.

And if you have solar covering your parking garage, like the City of Tucson, you could be charging while you work.

You can tell the smart utilities — they are the ones putting their lobbying power behind plug-in hybrids. It just makes cents.