I don't think cost per watt is that relevant. It's been the cheapest source of energy worldwide, at ~4 cents iirc, and falling. For several years now. The que

I don't think cost per watt is that relevant. It's been the cheapest source of energy worldwide, at ~4 cents iirc, and falling. For several years now. The question is no longer what to pick based on cost per watt: it's solar. Cost per Watt is relevant as a historical curve. Efficiency on the other hand provides an outlook. We can get 4x more efficient solar cells (theoretically). We are still getting manufacturing improvements and scaling effects. I would expect solar to break through the 1 cent per Watt barrier based on that.