That is, indeed, the question. We'll just have to wait and see how well it scales. If it isn't sufficiently efficient, then it's a really cool parlor trick.

I was reading today about concentrated solar power generation. One of the things they do to maintain power generation at night is using molten salt! I'm wondering if they might be able to sort of "bank" part of the output of igniting salt water to put it back into the generation loop.