Essentially. It could be entirely generated from sources of energy which could not be utilized for any other purpose. There is a world of untapped energy that is only restricted by isolation. So you could entirely run bitcoin without increasing global energy output, if that makes sense. There would be no opportunity cost of lost power to current grids, as it is using power that cannot be used for any other purpose.

In other words, transporting energy is usually the limiting factor. That’s why you can’t just have all your solar panels in the desert, for instance. Moving power is too difficult. But with Bitcoin, you don’t need to move the power, just the product. So think of all the energy currently devoted to printing money, or running the computer systems that prop up the global financial market - if you transitioned to Bitcoin, in theory all of that power could be saved, as Bitcoin would be entirely using power that cannot otherwise be used.