IIRC it worked by using a big gyroscope to stay stationary while the earth rotated, causing 1 rotation every 24 hours. So not technically free energy, just taking it from the earth

I was quite worried that he'd gone off the deep end when he published that video

The way I understood his "free energy"-device back in the day, was supposedly trying to induce a current into a set of coils from the very tiny discrepancies between the earth's rotation and that of its magnetic field. How the gyroscope would play into it, is anybody's guess (alignment, I suppose?). Obviously, none of this would work, and I don't think he was in a particularly good place back then.

I saw an artwork like this before, maybe by Anish Kapur?