@Phil to your solar idea, i think most time you would "only" get 90% of your max solar watt/panel. And if it drops because of the short? cloud it always fall down, and miner stops hard. Doesn't cool down, could be much cycles/day. Isn't it there where you are, you could get the same rate for solar, as from the grid?  Even if only in short times of clouding, you could get lets say 30-60% power from solar, and the rest from grid. And after sun is down, stop mining. Or is it to much expensiver if grid is avaible? How long miners need for startup?