Unbreakable laws of physics? (regarding power generation)

It is logically impossible to prove the Law of Conservation of Energy. All you can do is keep trying to disprove it. Calling it a "law" is unfortunate as the simple-minded get very attached to that concept. The human race has been doing "proper science" for about 200 years. In that time, an enormous number of theories and laws have been created and discarded. Newton's Law of Gravitational Attraction was demonstrated to be a special case when Einstein came along. There's no guarantee that the so-called Law of Conservation of Energy is any different.

Loopholes have already been found. Conventional wisdom has it that, for example, the energy released from combining hydogen with oxygen cannot be greater than the energy required for the electrolysis of water. There are, however, people who claim that by finding the resonant frequency of the water molecule, electrolysis can be instigated at much lower energy levels by applying AC at that frequency. Anyone who has seen the famous footage of the Tacoma bridge disaster will have some intuitive understanding of how powerful resonance phenomena can be. Why should it be impossible to apply this principle to electrolysis?

A rather good documentary was shown by Channel 4 in the UK a few years back, and it's available on Google Video - search on "It Runs on Water". Interestingly, one of the inventors profiled has since died, allegedly through poisoning. Many of the people involved in free energy projects seem to meet unlikely and untimely ends.