asynchronous parent
Way, way too much is the answer. That amount of storage alone has got to kill his electricity bill.
he said solar, which is pretty nice if (1) he is generating excess solar in the day (2) he cannot sell it back to the grid (3) it's not cost effective to store in batteries for night use (4) there's nothing else to spend the energy on.
otherwise, i can imagine it'll still be cheaper to not run things than to run things. but it's a hobby, people spend energy and resources on more frivolous things, and those frivolous things make us human.