For electric cars, fathoming their EPA mileage ratings is like reading the liability form of an Eastern European game show—there are so many stipulations, caveats, and wanton asterisks that EV owners tend to shrug their shoulders and spout off a triple-digit estimate. How many miles per gallon does it get? “Enough,” they say, “and I never have to use any gas!”
Accurate? Probably not. But that’s just an indication of how many consumers are left in the dark when it comes to electric car ratings. After all, they all consume something—whether it’s a shot glass of gasoline or a socket of electricity.
Case in point: The new Ford Focus Electric plug-in, which as its name suggests is a fully electric car—no onboard gasoline generator to power the electric motor like the Chevy Volt, no internal combustion engine to occasionally nudge the car forward like the Toyota Prius. Ford claims that it is the most efficient five-passenger vehicle, even more thrifty than the media darling Nissan Leaf, which can carry five people as well as their chorus of roominess complaints. But how do you rate miles per gallon when not a single gallon is being used?
The Environmental Protection Agency, which determines MPG ratings, uses what’s called “MPGe,” or miles per gallon equivalent. On a fundamental level, it seeks to determine the energy consumption of a car based on how far it travels—no matter if that energy comes from a gasoline-hybrid or electric motor. The EPA rates 33.7 kilowatt hours of electricity to be equal to one gallon of gasoline, which makes the MPGe figure more equivalent to our common MPG ratings.
Electric cars are run through the same (some would say outdated) EPA mileage tests as our gasoline-powered brethren. As the charge in the batteries runs down, the MPGe figure becomes more relevant. In this example, the Chevrolet Volt’s batteries consume energy at a rate of 36 kilowatt-hours, every 100 miles. Just like how a gasoline-powered car consumes one gallon per 25 miles, which equates to 25 mpg, the equivalent for the Volt is 93 MPGe.
In that case, Ford’s electric Focus was tested by the EPA to return 110 MPGe, the highest rating among all electric cars that the EPA has tested so far, and miles ahead of any gasoline equivalent. Ford is unsurprisingly pretty pleased with itself—it will just have to figure out how to explain this to legions of potential consumers, without coming under a hailstorm of media scrutiny. It won’t be an easy task.