Yesterday General Motors rolled out a bombshell: Their new 2011 Chevrolet Volt will get 230 mpg. The details were sketchy though. (Read: “2011 Chevrolet Volt: Fuel economy results may vary.”) The figure was according to the EPA’s new… uh… almost done… er “draft” testing methodology that they aren’t prepared to comment on.
Let’s cut through the hype and break this down:
The “230 mpg” marketing suggests that the Chevrolet Volt will somehow have equivalent energy costs to a conventional, gasoline-fueled car rated at 230 mpg. The official GM press release quickly points out the low operating costs and quotes the national average electricity rate of $0.11/kWh. Further down it points out that $2.75 worth of electricity will get you 100 miles of driving. All the figures were based on city driving.
Here comes the grain(s) of salt:
1. Let me repeat: $2.75 for 100 miles. Well, $2.75 isn’t far off from what a gallon of gas costs these days. So 100 miles for what it costs for a gallon of gas? It would seem that something like “100 mpg gas equivalent” (at least in terms of cost to the consumer) might be more meaningful. While it may not make as many headlines, it would still be a rating to be proud of.
2. While $0.11 per kWh is the national average, areas such as California, Connecticut, Massachusetts, New Jersey, and New York pay far more for electricity—notably states with major metropolitan areas well-suited to electrified motoring. Here at the Consumer Reports Auto Test Center in Connecticut we pay over $0.20 per kWh. At that rate, 100 miles would cost you about $5. In terms of fuel costs per mile, a Toyota Prius isn’t far off that figure in our testing. With moderate hypermiling, it is definitely possible.
3. While we are all ingrained with the fact that highway cruising is more fuel-efficient than city driving, the opposite is true for electrics. All the announced figures are for city driving. Driving the Volt at highway speeds is likely to use energy at a far quicker rate, and in turn activate the on-board gas engine acting as a generator.
4. Keep in mind that the Volt is designed to only go about 40 miles before relying on its auxiliary gasoline engine for charging the battery. Perhaps those 100 miles occur over three days? Or, the test allows for recharging—which seems disingenuous. The number suggests that in one trip, a driver can achieve the advertised number. Alas, that does not appear to be the case.
In the end, 230 mpg might be the exaggeration of the “century.” If you are a cyclist like I am, you may have heard about doing a “century,” riding 100 miles. But imagine that after you rode that distance, you found out that some agency has devised a way to calculate your ride as 230 miles based on the ratio of your front sprocket to wheel diameter, wind resistance, and the solar load on your front forks. Would you tell everyone that you rode 100 miles? Or would you say that you rode 230 miles based on a “draft” measurement that you can’t really talk about?
Turns out, we’re not the only one raising an eyebrow at this claimed figure. In a Tweet yesterday, Nissan claims 367 mpg for the electric Leaf based on the Department of Energy formula, also noting that its green machine will be priced significantly less than the expected Volt sticker. (Learn more about the Nissan Leaf electric car and see my colleague Jon Linkov discuss the Volt on the Today Show.)
The Chevrolet Volt has impressive technology, and GM deserves all the credit they get for bringing it to market. However, misleading announcements like this aren’t helping anyone and they create risks when real-world tests are eventually performed. What if the Volt doesn’t live up to the hype? Truly, we hope it does, but the numbers don’t add up. Ultimately, despite GM’s effort to regain their image as a technology leader, it may be practical sedans like the upcoming Chevrolet Cruze that matter more to GM’s bottom line.
See our earlier report: 2011 Chevrolet Volt: Fuel economy estimated at 230 mpg city and our Chevrolet Volt preview for more information.