Keeps your car cool in hot weather too.
When I lived in Glendale, California, they put parking structures with solar panels at the schools to generate electricity. And, the city of Glendale has its own steam power plant, so they are not paying a power company for electricity, anyway. It was one of the best-managed cities in the country, and is ranked 124th in the country in size. (I haven’t lived there since early 2015, so cannot testify to its current status, but suspect that is probably still true.)