One day after the all-electric Nissan LEAF received its 99-mpg (equivalent) rating from the EPA, General Motors announced the Chevy Volt will carry a rating of 93 mpg while running purely on electricity, and 37 mpg in so-called “charge-sustaining” mode.
While the EPA tries to pin 60 mpg as a single composite number for the Volt’s efficiency, the amount of energy consumed will greatly depend on how you drive, the distance of common commutes, and how often it’s charged. "If you try to boil it down to a single number, it gets quite difficult," said Tony DiSalle, Chevrolet product marketing director. To make matters more detailed and confusing, the EPA also said the Volt has a 35-mile range on electricity alone and a range of 379 miles with gasoline and electricity.
Maybe the only definitive conclusion that can be drawn from the Volt’s efficiency label is that we’ve entered into an exciting new era of automotive technology, in which it will be nearly impossible to establish a one-size-fits-all number for efficiency (or for green-ness, for that matter). Plug-in hybrids, such as the Chevy Volt, that run on both gasoline and grid-supplied electricity will be particularly difficult to pin down. The phrase “your mileage may vary” has reached a new level of meaning and importance.
The quest for useful efficiency metrics was not helped by G.M.’s earlier claims that, under the most favorable conditions, the Chevy Volt will get 230 mpg; that it’s all-electric range is 40 miles; and that it will earn as much as 50 mpg after the gas engine is brought into service.
The Chevy Volt goes on sale in a few weeks. When drivers begin to report their energy consumption (and G.M. tracks usage via its communications network), a composite or average number for the “real-world” will begin emerge. Given the passions of plug-in drivers and how much G.M. has riding on the success of the Volt, even those numbers are not likely to quiet the debate about the benefits of electric-drive technologies—but one other thing is clear: plug-in electric cars like the Chevy Volt and Nissan LEAF represent a major breakthrough in fuel efficiency.
Download a high-resolution image of the Chevy Volt label.