Complicated but certainly a profitable set up.
Using the sun to mine Bitcoin is quite a great idea. It should work in the long run as the electricity is FREE. It takes a lot of skills to do that. I wonder how much you'd spend for such set up.
No, it's not free. Do the math and you'll see that the price of kW⋅h in such farm will be higher than in a country where electricity is the most expensive.