As long as input energy required doesn’t scale in a 1:1 relationship to the output, shouldn’t matter what that input is - I think.
Discussion
Yep, have to “maintain the gain” otherwise it’s all futile. Lots of obstacles ahead to overcome. Biggest ones are how do they sustain the energy long enough to get or harness that excess energy and remove it from the system so it can actually be used? And the cost to run it all ultimately has to be priced competitively in order to make it a viable competitor to other energy sources.