General Motors today said that the Chevrolet Volt (pictured) will get 230 miles per gallon in city driving. Expressed in electrical terms, that means an electrical efficiency of 25 kilowatt hours per 100 miles traveled, according to the company. The claim is based on a draft EPA fuel economy methodology for labeling plug-in electric vehicles. The Volt will be released in the 2011 model year, says the company in a release, and will go 40 miles on a single battery charge that will extend to more than 300 miles with its flex-fuel powered engine-generator. Eighty percent of commuters travel less than 40 miles per day, according to  federal transportation statistics. "From the data we've seen, many Chevy Volt drivers may be able to be in pure electric mode on a daily basis without having to use any gas," said GM CEO Fritz Henderson, who called the mileage figures for the Volt "a game changer."

When the battery reaches a minimum state of charge, the Volt automatically switches to Extended-Range mode. In this secondary mode of operation, an engine-generator produces electricity to power the vehicle. The energy stored in the battery supplements the engine-generator when additional power is needed during heavy accelerations or on steep inclines.

Photo © General Motors