Ford Motor Co. partners with Southern California Edison to test a fleet of plug-in hybrid-electric vehicles, The Associated Press reports.

The utility, which provides service to some 13 million people in 11 Southern California counties outside Los Angeles, will receive one Ford PHEV by the end of this year and up to 20 by 2009.

The program will be used to test the vehicles’ durability, range and impact on the power grid, says Susan Cischke, Ford senior vice president-sustainability, environment and safety engineering.

The utility also will place cars with consumers and collect data for Ford, Cischke says.

Like traditional hybrids, such as the Ford Escape Hybrid and Toyota Prius, PHEVs utilize both gasoline and electric engines for propulsion.

However, PHEVs can be plugged in to a standard household wall outlet, greatly increasing their range in electric-only mode.

Ford has not announced when it would offer a production PHEV for sale to consumers.