Sun is not free. Sun requires land. If (and I don't think we're there yet) you can get to where the sun gathered by PV can be used to grow more plants than dire

Sun is not free. Sun requires land. If (and I don't think we're there yet) you can get to where the sun gathered by PV can be used to grow more plants than direct sunlight, and you're in a space constrained place like Japan, it starts to make sense. I mean, you can stack farms vertically if artificial light is economical. You can't stack sun-lit farms vertically.