Even if you assume launch cost = zero its most expensive and less practical.

And the moon is even worse. Still you can assume launch cost = zero. But energy is one part, to actually reliably land on the moon with your whole infrastructure. Connecting all that infrastucture up with power and everything else.

Your basically doing a gigantic civil engineering project all with only roboitcs, while we can't even do a civil engineering project on earths with only robots.

And if your going moon, nuclear is clearly the better option then solar towers. And if you go nuclear anyway, just do it on earth.