parinoid

Proton exchange fuel cells come darn close though. But yes, the law of phyics are upheld here (specifically the laws of thermodynamics) the energy required to seperate the atoms is always the same, however the energy lost due to resistance is what is changed by the electrolyte. The reverse reaction releases ALL of the energy use to split the water apart regardless of form. This is true for all reactions. In short what UC said (plus mentioning the ultimate laws of thermodynamics!)