The "super credits" for electric cars were one of the more discussed nuances of the revised CAFE standards proposed by the Obama Administration earlier this year. Under the new standards, automakers will be required to boost their blended mileage to 35.5 miles per gallon by 2016, a 40 percent increase. These cars are also supposed to only emit 155 grams of carbon dioxide per kilometer.

To encourage electric cars and plug-ins, the Environmental Protection Agency has been discussing counting each electric as more than one car. With such a regulation, automakers might make more of them if they find they are hitting a wall in mileage improvement with larger cars.

The EPA has been somewhat vague about the exact definition or standard of the super credit. Daniel Sperling, a professor of civil engineering and the founder of the Institute for Transportation Studies at UC Davis, though, said at the Almaden Institute being hosted by IBM this week that the agency is toying with the idea of counting an electric car as three cars and counting its emissions as zero.

If that comes to pass, it's a pretty good gimme. Electric cars may not emit fumes at the tailpipe, but the power plants that provide the electricity likely will. In some heavy coal states like Ohio or even the diesel-generator dependent Hawaii, electric cars may not provide much of a benefit when it comes to emissions reductions. (In most places, the emissions reductions will be substantial.)

On the other hand, electric cars will likely cost more for several years because of the state of the battery industry. Hybrids, despite their visibility, only account for around 3 percent of car sales in the U.S.

We haven't had a chance to call the EPA on the one-two-three idea, but Sperling hangs out quite a bit in Washington. We will let you know more as we go on.