See: http://www.pnl.gov/news/release.asp?id=204
Mileage from megawatts: Study finds enough electric capacity to "fill up" plug-in vehicles across much of the nation
RICHLAND, Wash. If all the cars and light trucks in the nation switched from oil to electrons, idle capacity in the existing electric power system could generate most of the electricity consumed by plug-in hybrid electric vehicles. A new study for the Department of Energy finds that "off-peak" electricity production and transmission capacity could fuel 84 percent of the country's 220 million vehicles if they were plug-in hybrid electrics.
Researchers at DOE's Pacific Northwest National Laboratory also evaluated the impact of plug-in hybrid electric vehicles, or PHEVs, on foreign oil imports, the environment, electric utilities and the consumer. . . .

