Program draws on $705 million set aside in an economic stimulus package earlier this year but leaves many financing details up to the next government.
In a survey of customer satisfaction, American-made brands pull even for the first time in a decade. GM's Cadillac ties for first place.
Detroit has not said whether it will boost auto production now that Congress has allotted $2 billion more to the program.
The Energy Department made the announcement Tuesday, just as Nissan said it will start selling an all-electric car in the US next year.
The Monitor's language columnist looks at the quintessential quindecennial and other celebrations.
At least nine major car companies promise plug-in vehicles by 2013.
EarthTalk: Many of them now offer hybrid models – for a price.