We don't really have similar parking lots here in Europe as opposed to America. But there's plenty of space on rooftops of all sorts of buildings. My municipality? built a solar park out in some space that was previously used for farming and is reaping benefits from it. But with just a bit more effort it could've been placed atop existing buildings there were a number of big buildings nearby even that could've supported it.

Everything that's built new should have rooftop solar incorporated in the design anyway imo. Our administrative building for the municipality is getting plastered with solar on top of getting a new insulating roof btw in the very near future. I think it might be happening atm.