[biaachmonkie]

Building roofs, parking lots, streets, rail tracks, etc.. are all spaces that could have a canopy installed overhead and solar panels providing power and shading. As solar panels continue to lower in cost the sides of buildings, fences, etc.. There are lots of opportunities to install solar panels in a crowded city.

[pzo]

maintaining such infrastructure would be really costly: installing extra canopy, cleaning, removing snow (not easily accessible), extra inverters. I think solar only make sense if it's installed as solar farm (easy to maintain by one company) or in residential houses (owner maintain) or commercial units (owner maintain it). Solar prices went down but cost of installation and maintaining not much - this is the reason why many people in my family didn't buy it since it's still big investment and maintenance burden currently not worth the effort unless you are building new house.