Jonas Knudsen

So, I'm doing a project on fuel cells and therefore I am looking into Hydrogen production. Now the most promising one to me was Green Hydrogen. Or in other terms using renewable energy to drive electrolysis, creating Hydrogen and Oxygen. But where would we get the water, without destroying whatever climate we're taking it from? I can't imagine sucking thousands of liters of water from a lake or the ocean to be a good idea.

So I was looking into Hydrogen fuel cells, and it says that there is a loss of energy. But I don't see where the loss is unless thermal energy is expelled in the ionization of the Hydrogen.