The Prius Gen 3 had an option for a 'solar roof', but it's pretty much just a gimmick. The whole roof is 40W. All the panels do is power a fan to bring exterior

The Prius Gen 3 had an option for a 'solar roof', but it's pretty much just a gimmick. The whole roof is 40W. All the panels do is power a fan to bring exterior air into the cabin, to keep it cooler during hot weather.