How about hanging solar panel vertically on tall buildings covering every floor except the first few to prevent vandalism

As the earth moves the sun would only hit one side and lose efficiency but right now it's "free space" not being used otherwise

They even make flexible solar panels now that can bend and move with the wind and don't need a stiff frame, slightly less efficient but volume makes up for that

Clean them the same way automated window washers work on skyscrapers

Shame they never came up with the solar paint solution, yet