Next-Gen Prius: What Will a Little Sunshine Get You?

Automaker Toyota will include solar panels on some of its new cars, according to reports in Japan's Nikkei newspaper. Toyota will add the energy-catching panels to the roof of its hybrid Prius as soon as Spring 2009.

The panels would reportedly be used to power the Prius' electronics -- specifically the air conditioning system, which would need two to five kilowatts of energy to run. Details are few, but Toyota plans to deliver a third-generation redesigned Prius next year.

The Prius is a gasoline/electric hybrid that captures the kinetic energy normally lost during braking, as well as using its gasoline engine, to charge its battery. The Prius then runs on electric power whenever it's most efficient to do so.

Avoiding the Pump

Automakers around the world are racing to produce vehicles that can beat rising gasoline costs. However, despite the promise of using electricity for vehicle drivetrains, solar panels are a long way from completely powering a car's engine. Even if a driver could avoid rain clouds and count on plenty of sunshine, the surface area of a typical car -- or Prius, for that matter -- isn't able to harness enough energy from the sun to propel the Prius.

"Car rooftop panels can provide only enough energy for vehicle cooling while parked, maybe a small contribution while driving," Felix Kramer, founder of CalCars, told TechNewsWorld. CalCars is a nonprofit organization that promotes plug-in hybrid electric vehicles (PHEVs).

"This story will get lots of attention and will give people the impression Toyota is doing something pioneering, unique and valuable. We wish Toyota would instead focus on rapid progression to PHEVs. By far the largest leap comes from adding a larger battery and grid-charging so the vehicle can have an energy source besides gasoline," Kramer explained. For the foreseeable future, he noted, solar cells belong on buildings, including garages, where they can be made larger. Also the auto-related issues of durability and aerodynamics are not a big challenge when solar panels are built into a standing structure.

Selling Fast

Worldwide, Toyota reports that it has sold well over a million Prius vehicles, and more than 591,000 have been sold in North America. The company estimates that Prius hybrids have contributed to a reduction in greenhouse gas emissions of approximately 4.5 million tons of CO2 compared to non-hybrid, gasoline-powered vehicles in the same class and of similar size and driving performance.

The 1.5 L 4-cylinder, four-door Prius Hybrid gets up to 48 miles per gallon, making it -- according to the United States Environmental Protection Agency (EPA) -- the most fuel-efficient car sold in the U.S.

Mazda briefly manufactured a sedan -- the Eunos 800 -- in the 1990s that sported a solar panel that was used to charge the battery and remove hot air from the interior during hot sunny days; however, the vehicles never really took off in sales .