New EPA Numbers Promote Confusion About EV Efficiency
The U.S. Environmental Protection Agency released efficiency numbers for the Coda Sedan, assigning a rating of 73 MPGe. Okay, that's disappointing compared to the LEAF's 99 MPGe, the Ford Focus Electric's 105 MPGe and the Mitsubishi i at 112 MPGe. On the other hand, because the Coda has the biggest battery of the bunch, it beats all other EVs with an EPA "miles on a charge" rating of 88 miles.
These numbers seem designed to instill confusion.
In August 2010, before any of these ratings came out, I spoke with Mike Duoba, a research engineer at Argonne National Lab who serves as chair for the Society of Automotive Engineers' committees related to EV efficiency. He warned not to dumb down the numbers. Duoba said that MPGe (or miles per gallon equivalent) numbers would be too high to make any sense. “Any time you go over 100 miles per gallon, depending on how you’re calculating things, you’re going to really confuse people,” Duoba said. “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.” He was talking about GM's campaign at the time to promote a 230-mpg rating for the Chevy Volt, to which Nissan replied that the LEAF would get 367-mpg if measured in the same way.
While the numbers have come down to a more earthly reality, according to the EPA, the difference in real-world cost or driving experience between the electric equivalent of 75 miles per gallon of gasoline versus 100 or more remains difficult to grasp.
With EPA certification now complete, the Coda Sedan is ready to launch. Initially, Coda will only sell one version of its electric sedan priced at $37,250. Coda is planning to hand over keys to the first electric Sedans in the next week.
As an unknown brand with an unproven car with a dull design, Coda faces more than its share of challenges in the emerging electric car marketplace. Unfortunately, the low and confusing numbers from the EPA don't make life any easier for Coda, or for that matter, the entire growing field of EVs.
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