Anyone worried about the price of buying a hybrid probably won't go for this option. According to the Nikkei business daily, Toyota may offer solar panels on the roof of the next generation Prius as an option on their high end model.
Personally, I can't see how that would be at all interesting or necessary, but I know there are those out there who would be excited about the prospect. Aside from the 'cool' factor, solar panels would help them differentiate themselves from the crowd of other Prius owners. Also, the more solar panels are used, the more likely the price will drop and the more effective they will become.
The solar panels, if they are really used, would be used to power the air conditioner.
Source: Toyota to add solar panels to Prius hybrid: Nikkei | Reuters
Toyota plans to use solar panels made by Kyocera Corp (6971.T: Quote, Profile, Research, Stock Buzz), the Nikkei said.