http://www.sfgate.com/cgi-bin/article.cgi?...MNGT7R3OH81.DTL

A study released Thursday by the Palo Alto-based Electric Power Research Institute and the Natural Resources Defense Council confirmed what advocates of plug-in vehicles had long suspected: Hybrid electric cars, if widely adopted in the United States, would yield huge reductions in greenhouse gases over today's fleet of gas-fueled cars and hybrid vehicles.

"The studies finally give an environmental stamp of approval" to plug-in vehicles, said Felix Kramer, founder of CalCars.org, which promotes electric hybrids. "Scientist have confirmed that unlike gasoline cars, plug-ins will get cleaner as they get older -- because our power grid is getting cleaner."

The study found that if 60 percent of Americans shifted to plug-in hybrids by 2050, it would lead to an increase in electricity usage of 7 to 8 percent -- a relatively small increase, indicating that hybrids would not necessarily require a surge of new power plant construction. Plug-in hybrids are charged mostly at night, when demand for electricity is low.

At the same time, the report estimates that electric hybrids would displace the need for 3 million to 4 million barrels of oil per day by 2050, more than twice what the United States imports each day from Saudi Arabia.