Solar panels are starting to show up on a few new cars such as the upcoming version of the Prius, but until now there have been no options for upgrading existing cars. Now a company called Sunrise Solar plans to offer a line of drop in replacement sunroof panels, as an easy way to add solar power to any car with a sunroof. While such a small area can't generate a lot of power, it would be enough to keep a charge on the car's battery, or to run a fan that draws cooler air through the car when parked on a hot day. This would make the car less stifling when you first get in, reducing the need to blast the fuel economy sapping air conditioning.
So far, Sunrise Solar's website has only sketchy information with nothing about prices or availability.