How well does it work covered with a foot of snow? In the dark? When its cloudy?
Probably not too well. I see this as a solution in areas south of the Mason-Dixon.
As for the dark and cloudy times, I don't see ever getting completely off of the grid with this technology. It won't soon replace coal, nukes, or gas fired plants completely. But it will certainly supplement them.
During the day when I'm not home, my house could be a net producer of energy on the grid, which I sell back to the power company via a two-way meter. At night I would be a net consumer on the grid. The power company would act as a battery from my point of view.