Neither General Motors nor the EPA are making declarative statements about how, exactly, the 2011 Chevy Volt will achieve it’s much-touted 230 mpg rating that was announced today. GM’s most clear statement (available in full after the break) says that some consumers “may be able to be in pure electric mode on a daily basis without having to use any gas” and that “key to high-mileage performance is for a Volt driver to plug into the electric grid at least once each day.” Without access to the actual method that the EPA is tentatively going to apply to plug-in vehicles (we have requests for clarification out to the EPA), all that GM’s Dave Darovitz would tell us is that the number is “based on city cycles and we’re not really talking in detail yet.” Instead, the press release says that:
Under the new methodology being developed, EPA weights plug-in electric vehicles as traveling more city miles than highway miles on only electricity. The EPA methodology uses kilowatt hours per 100 miles traveled to define the electrical efficiency of plug-ins. Applying EPA’s methodology, GM expects the Volt to consume as little as 25 kilowatt hours per 100 miles in city driving. At the U.S. average cost of electricity (approximately 11 cents per kWh), a typical Volt driver would pay about $2.75 for electricity to travel 100 miles, or less than 3 cents per mile.
Frank Weber, vehicle chief engineer for the Volt, told AutoblogGreen that the EPA’s method takes into account the two extremes: People who plug in every chance they get and therefore barely ever need gasoline and people who never plug in (if you’re buying a Volt and never plug it in, we’d like to offer you a bridge or two. Call us). By figuring out what the average driver will do with the Volt, the EPA has declared that 230 mpg is reasonable. Weber said, “The number is in the ballpark, it is not unrealistic. The moment you are driving shorter trips, or you go on longer trips and look at your average fuel economy, this number is achievable.”
Keep in mind, the 230 mpg number is only valid for the Volt’s city cycle. On the highway, the number will be closer to 100 mpg. Still impressive to look at, and the first car to get triple digits from the EPA. As you can read in this detailed PDF from NREL, there is much more to think about in calculating the fuel economy of PHEVs than simply how far it can go on a single charge and then what its “regular” mpg rating is. At least, there’s more to it if you’re the EPA.
[Source: GM, NREL, Consumer Reports]