Because it goes dark every night.

Because solar farms are disastrous to the environment as they sterilize the ecosystem in their shade.

Because Thorium is neither rare nor cumbersome.

Thorium isn't rare. You probably have enough in your lawn to supply your lifetime energy needs. Also, it's a waste product of rare earths mining, and there's a United States stockpile of 3.2 million kg of thorium nitrate that nobody knows what to do with.