California became the first state in the nation to require homes built in 2020 and later be solar-powered, following a vote by the Building Standards Commission. The unanimous action finalizes a previous vote by the Energy Commission and fulfills a decade-old goal.

Source: California officially becomes first state to require solar panels on new homes – Los Angeles Times

When France did this they gave you a choice between PV or a green roof. It seems to me that in urban areas, the effects of the green roof — cleaning the air, moderating temperature, absorbing rain/reducing runoff, providing an amenity for people and habitat for birds — may outweigh the relatively small amount of power produced by rooftop PV. Then put utility-scale solar in the desert.