For a minute there I thought you were going to cite Chariot of the Gods? by Erich von Daniken as your unimpeachable source.
No, I actually read it in a magazine some time back. Late 80's early nineties I think (does not imply that was or was not when it was built, just an article on the endeavor). It was supposedly tested at some university and discovered, or measured, the electrical properties generated.
The quote provided was what I could find that came close to what I'd read. IIRC