NEXT L.A.: A look at issues, people and ideas helping to shape the emerging metropolis. : Tapping the Solar Source

Straight from the sun, the latest breakthrough in clean fuels involves a solar-powered Ford Ranger pickup truck.

The only exhaust emitted is water vapor.

A joint project of Xerox Corp. and Clean Air Now, an environmental group, the experimental technology to be unveiled today in Los Angeles makes hydrogen fuel from sunlight concentrated in photovoltaic cells.

Stored in high-pressure containers at a Xerox plant in El Segundo, the solar hydrogen will fuel a fleet of pickup trucks with internal combustion engines that have been modified to run on the gas.

The trucks, some of which will be operated by the city of West Hollywood, are expected to be able to travel 60 to 120 miles before refueling, said Paul Staples of Clean Air Now.

Solar hydrogen technology is still in a comparatively early stage of research and development, experts say, but they don’t rule out the possibility that it could one day replace electric power as the cleanest and most efficient approach to zero-emission vehicles.