Unless have a fusion reactor, hydrogen is not an energy source. It takes energy to break a hydrogen atom from a water molecule - not coincidentally the same amount of energy that is released when it is burned. The energy has to come from somewhere else.

This invention, if it works, is basically a better battery. Hydrogen is attractive for this purpose because it burns clean but it’s a pain to store and transport. It would be great to solve those problems. It’s not free energy though.