I think Steven is right. This is a long way out. It must take hundreds of thousands of space launches to move this huge amount of material into the proper orbits? Have they computed the energy and greenhouse gas cost to do that? Perhaps some basic research on mono-layer thin solar films is in order.

I am convinced that we could do a much better job of making public transportation really work. Dedicating certain streets for buses only, and making sure they always get green lights would help. Also, in cities anyway, they should be free. Most city buses are already heavily subsidized, so why not go all the way. Then the buses would be fast and convenient, so most people would end up using them so we wouldn't resent our tax dollars being spent on something we don't use.