 In August 2009 , General Motors released its estimated city fuel economy rating for the Volt of 230 mpg @-@ US ( 1 @.@ 0 L / 100 km ; 280 mpg @-@ imp ) of gasoline plus 25 kWh / 100 mi ( 560 kJ / km ) of electricity using the EPA 's proposed method for evaluating plug @-@ in hybrids . The U.S. Environmental Protection Agency ( EPA ) issued a statement clarifying that the " EPA has not tested a Chevy Volt and therefore cannot confirm the fuel economy values claimed by GM . " In July 2010 , GM explained that their estimate was based on a formula that had not been officially approved and that they had been awaiting the EPA 's decision on how the equivalent fuel economy of plug @-@ in hybrids would be estimated . 
