EV Window Stickers Still Aren’t Helpful and It Doesn’t Really Matter

By · March 06, 2018


What does 119 MPGe really mean? Will you really save $4,000 in fuel costs? The Chevy Bolt’s window sticker is not helpful.

It’s been about eight years since the U.S. Environmental Protection Agency redesigned vehicle window stickers to help consumers understand the efficiency of plug-in electric vehicles. At that time, we discussed the potential confusion over dumbing down window stickers with fuel-economy terms that don’t carry over to EVs.

Nearly 800,000 plug-in sales later, not much has changed. This week, Sebastian Blanco—formerly the editor of Autoblog Green and now a contributor to Automotive News—revisits the subject, comes to a similar conclusion.

At the center of the confusion is the term MPGe (or miles per gallon equivalent). In 2010, Mike Duoba, chief engineer at Argonne’s Advanced Powertrain Research Facility, told us, “Trying to boil the information down to one number is only going to mislead people. There’s no magical way to turn electricity into gasoline.”

The Automotive News story echoes the sentiment in 2018. “While in principle MPGe is a good way of conveying relative efficiency, I'm not sure that it’s actually meaningful to consumers, nor is energy efficiency in general for plug-in vehicles," said Sam Abuelsamid, senior analyst at Navigant Research, to the trade publication. He believes that buyers of pure EVs are mostly interested in total range on a single charge—and for plug-in hybrids the key is gasoline efficiency after the charge is depleted. (We would add that the number of miles that a plug-in hybrid can travel purely on electricity is a vital number.)

We're Stuck But That's Okay

Blanco reports that, despite rumblings, there is little to no momentum for changing the stickers. The process that led to the current sticker took two years to complete—with focus groups, panels, and surveys. “We do not have plans to initiate a rule-making that would change or update the label,” an E.P.A. spokesperson told Blanco.

So, it looks as if we’re stuck with MPGe for an indefinite period. That metric converts how many kilowatt-hours it takes to go 100 miles compared to 33.7 kWh, which is the amount of energy in a gallon of gasoline. An EV that uses 25 kWh to go 100 miles would get 134.8 MPGe.

“Any time you go over 100 miles per gallon, depending on how you’re calculating things, you’re going to confuse people,” Duoba told PluginCars.com in 2010. “The difference between 200 miles per gallon and 300 miles per gallon can fit into a thimble. As the numbers get higher, the amount of fuel we’re talking about is tiny.”

The use of MPGe concedes that an EV is very efficient—and that’s about it. Here’s the silver lining: EV buyers are likely to be better informed about efficiency issues compared to the average car buyer. Electric-car shoppers can find use a wide range of online sources to determine the efficiency level of various cars on the market. And in the Internet age, very few of us rely on the window sticker to help us make an informed decision.

In our guide to buying a plug-in car, we offer this advice:

A few years ago, a window sticker with 100 m.p.g. or more was unimaginable. Now, the entire segment of plug-in cars is offering efficiency at or close to that level. Automakers frequently market their efficiency numbers, especially when they are higher than the competition. But truth be told, all electric cars have very similar levels of efficiency. Lighter EVs driven carefully will get about four miles per kilowatt-hour. Heavier EVs driven with gusto will get about three miles per kilowatt-hour. Most of us settle somewhere in between. At the end of the day, here’s all you need to know: All EVs are much more efficient than gas cars.

New to EVs? Start here

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