I think it certainly could be cheaper over the time scales relevant for Kardashev scale. But we have plenty of time to worry about that later. But we need to f

I think it certainly could be cheaper over the time scales relevant for Kardashev scale. But we have plenty of time to worry about that later. But we need to figure out how to survive the next couple of centuries before we start worrying about efficiencies that will matter in tens of thousands of years, and rooftop solar certainly helps in the immediate term.