The Chevy Volt, General Motors says, should earn an EPA rating of 230 mpg.  The Nissan Leaf will beat that, its builders say, with a 367 mpg rating.

The EPA isn’t so sure.

USA Today reports, “The concept of judging fuel efficiency on electric cars by the ‘miles per gallon’ they consume is dying a slow death. The EPA and other government agencies are working on a formula that will accurately tell people how fuel efficient electric vehicles are — but since those cars don’t use gas, miles per gallon doesn’t make any sense.”

GM and Nissan based their claims, the New York Times explains, “on a draft Environmental Protection Agency standard for plug-in hybrids and battery cars. But the agency says that work isn’t complete, and it is searching for meaningful ways to present the information to car buyers on the window sticker.”  The agency may never use the standard GM and Nissan used to back up their claims.

But developing a new standard is a controversial process. The Times reports, “Automakers and environmentalists interviewed have their own take on what an ideal E.V. window sticker would look like.” More