Ask Joe Mechanic - Solar Powered Vehicles (Part 2)

It is also possible to use solar panels to extend the range of a hybrid or electric car, as incorporated in the Fisker Karma, available as an option on the Chevy Volt, on the hood and roof of "Destiny 2000" modifications of Pontiac Fieros, Italdesign Quaranta, Free Drive EV Solar Bug, and numerous other electric vehicles, both concept and production. In May 2007, a partnership of Canadian companies led by Hymotion added PV cells to a Toyota Prius to extend the range. SEV claims 20 miles per day from their combined 215W module mounted on the car roof and an additional 3kWh battery.

On 9 June 2008, the German and French Presidents announced a plan to offer a cedit of 6-8g/km of CO₂ emissions for cars fitted with technologies "not yet taken into consideration during the standard measuring cycle of the emissions of a car". This has given rise to speculation that photovoltaic panels might be widely adopted on autos in the near future.

It is also technically possible to use photovoltaic technology, (specifically thermophotovoltaic (TPV) technology) to provide motive power for a car. Fuel is used to heat an emitter. The infrared radiation generated is converted to electricity by a low band gap PV cell (e.g. GaSb). A prototype TPV hybrid car was even built. The "Viking 29" was the World’s first thermophotovoltaic (TPV) powered automobile, designed and built by the Vehicle Research Institute (VRI) at Western Washington University. Efficiency would need to be increased and cost decreased to make TPV competitive with fuel cells or internal combustion engines.

A Swiss project, called "Solartaxi,” has circumnavigated the world. This is the first time in history an electric vehicle (not self sufficient solar vehicle) has gone around the world, covering 50000 km in 18 months and crossing 40 countries. It is a road-worthy electric vehicle hauling a trailer with solar panels, carrying a 6 m² sized solar array. The Solartaxi has Zebra batteries, which permit a range of 400 km without recharging. The car can also run for 200 km without the trailer. Its maximum speed is 90 km/h. The car weighs 500 kg and the trailer weighs 200 kg. According to initiator and tour director Louis Palmer, the car in mass production could be produced for 16000 Euro. Solartaxi has toured the World from July 2007 till December 2008 to show that solutions to stop global warming are available and to encourage people in pursuing alternatives to fossil fuel. Palmer suggests the most economical location for solar panels for an electric car is on building rooftops though, likening it to putting money into a bank in one location and withdrawing it in another.

Solar Electrical Vehicles is adding convex solar cells to the roof of hybrid electric vehicles. An interesting variant of the electric vehicle is the triple hybrid vehicle—the PHEV that has solar panels as well to assist.  The 2010 Toyota Prius model has an option to mount solar panels on the roof. They power a ventilation system while parked to help provide cooling. There are many applications of photovoltaics in transport either for motive power or as auxiliary power units, particularly where fuel; maintenance, emissions or noise requirements preclude internal combustion engines or fuel cells. Due to the limited area available on each vehicle either speed or range or both are limited when used for motive power.

Some information obtained from Wikipedia.org.