Maybe study thermodynamics instead. Free energy devices, perpetual motion, these concepts are physically impossible.

You know, it's kind of the job of those making the claim to attempt the prototype (and then to demonstrate, publicly, that it works).

It's not the skeptics' job to make the prototype. (And if they did, the true believers could just say "you didn't do it right".) The burden of proof is on you (and, even more, on the authors of the website, if there's any difference). Don't ask your critics to do your job.

In history of mankind no one has shown a working „free energy“ generator.

Id someone can do, jackpot richest man on earth, Nobel price and happy life.

Every single claim ever was a scam or failure.