Using Solar Roofs To Power Hybrids

http://www.treehugger.com/files/2007/05/solar_hybrid_ca.php#1

A company called Solar Electrical Vehicles is specializing in adding a convex solar roof to hybrid cars like the Toyota Prius, Highlander Hybrid and the Ford Escape Hybrid. The solar modules are rated at 200-300 Whr, and this power is utilized to charge a supplemental battery. With the solar roof, the Toyota Prius can operate up to 20 miles per day in electric mode thus improving fuel economy by up to 29%.