To make my calculation clear: 21 * 10^9 dollars / 1 * 10^9 W = 21 $/W Those are just watts at peak power, which are probably roughly 10x average power produce

To make my calculation clear: 21 * 10^9 dollars / 1 * 10^9 W = 21 $/W Those are just watts at peak power, which are probably roughly 10x average power produced by panels, at least on the earth. But perhaps I was too hasty in that the major hit against solar panel production is the earth obscuring the sun at night. On the other hand, I would expect cells in space to heat up substantially, given that they have no air to conduct away the heat. If I could, I'd edit my comment to clarify that my comparison was not fair-- I was comparing two systems with different capacity factors as if they were the same.