I would love to see this stuff become mainstream. Whether or not you could "power a building" based on its windows alone, it would be wonderful if all you did was provide for some climate control (A/C in summer, Heat in the winter). A passively maintained environmental system would be very helpful, one of the reasons people first started living in caves was that the cave provided some moderation of temperature swings outside based on the thermal mass of the earth around it. Large scale sustainable group housing is something we need.