General Motors has unveiled a Silverado hybrid which has a rechargeable battery that has a 2.4-kilowatt AC power outlet. When the vehicle is parked, the battery can be plugged in a socket to recharge it.
Currently, many people are paying $2 a gallon for gas in the US. It is estimated that the Silverado needs 60 cents per kilowatt-hour. Most people pay 8.5 cents per kwh and less at night which would be the optimum time for a battery recharge.
The writers of the article say that this technology could help the US save 200 million barrels of foreign oil. But because electricity is needed to recharge batteries, 40 million tons of U.S. coal could be needed. Some environmentalists are wary. Source