With California laws mandating emission-free vehicles this decade, more solar-electric carmakers are silently taking off. Solectria, a year-old company in Waltham, Mass., has sold six of its $26,000, four-seat vehicles, mainly to utilities. Powered by electric and photovoltaic batteries, the car -- a rebuilt Chevrolet Geo called The Force -- can travel up to 80 miles a day and reach a top speed of 60 miles per hour, all for a dollar's worth of electricity. Until volume drives down price, founders James Worden and Anita Rajan are targeting environmental interest groups and corporate fleets.

-- Anne Murphy