One time I was researching Prius battery replacement and I found some comment that regenerative braking was only the beginning, they needed solar panels, wind turbines, and some other bit of perpetual motion. As I recall, Toyota said "Solar panels are not cost-effective on a car."
"Shut up and take my money!"
"Toyota is pleased to announce rooftop solar panels!"
Someone told me that solar cars were as feasible as wind-powered ones, although didn't the A Team make one of those?
