Solar car

A solar car is an electric vehicle powered by solar energy obtained from solar panels on the surface of the car. Photovoltaic (PV) cells convert the sun's energy directly into electrical energy. Solar cars are not practical day-to-day transportation devices at present, but are primarily demonstration vehicles and engineering exercises. Solar cars compete in races (often called rayces) such as the World Solar Challenge and the American Solar Challenge. These events are often sponsored by government agencies, such as the United States Department of Energy, who are keen to promote the development of alternative energy technology (such as solar cells). Such challenges are often entered by universities to develop their students' engineering and technological skills, but many professional teams have entered competitions as well, including teams from GM and Ford.

Practical applications
Solar cars achieve their performance by extreme lightness of weight, and very efficient aerodynamics that force compromises that would not be acceptable in a day-to-day transportation device. Any vehicle built for passenger comfort and meeting contemporary safety standards would be much less aerodynamic and much heavier, thus requiring much more power to achieve highway speeds. Therefore, with current and foreseeable technologies it is unlikely a pure solar car will become commercially available. However, solar cars are essentially electric cars with an inbuilt recharging capability, so some of the engineering knowledge and technology developed in competition solar cars may help the development of battery electric vehicles and even hybrid vehicles. The Venturi AstroLab in 2006 was hailed as the world's first commercial electro-solar hybrid car due to be released in January 2008.
The question arises as to whether, if battery electric vehicles become popular, it will be worthwhile fitting them with solar cells to extend their range and allowing recharge while parked anywhere in the sun. However, with present and near-term engineering considerations, it seems that the best place for solar cells will generally be on the roofs of buildings, where they are always exposed to the sky and weight is largely irrelevant, rather than on vehicle roofs.
One practical application for solar powered vehicles is possibly golf buggies, some of which are used relatively little but spend most of their time parked in the sun.

Alternative Energy

From wikipedia