Toyota is planning to put solar panels on the new edition of its Prius hybrid car, according to the International Herald Tribune.

The manufacturer is refusing to comment but the informant said that the solar panels would be used to provide power for an air-conditioning system.

"It is more of a symbolic gesture," said the person, who asked not to be identified because he was not allowed to speak publicly. "It is very difficult to power much more than that with solar energy."

Kentaro Endo, a director at the Ministry of Economy, Trade and Industry in Japan who specialises in renewable energy, agreed that the application of solar energy is severely limited in vehicles.

"Even if you laid solar panels on the entire roof of a house, you only generate enough energy to run two hairdryers," he said.

"It is an interesting idea, but it would be very difficult to power a whole car, even with technological advances."