I've got a problem. I tried to see what would happen when putting a fuel cell and electrolysis in a circle. I end up with infinite energy, so I must be doing something wrong. Electrolysis 4 H2O -> 4 H+ + 4 OH- 4 H+ + 4 e- -> 4 H -> 2 H2 || The H2 is lead to the fuel cell anode 4 OH- -> O2 + 2 H2O + 4 e- || The O2 is lead to the fuel cell cathode, the electrons continue down the circuit to the fuel cell cathode The electrons complete the circuit Fuel Cell 2 H2 -> 4 H+ + 4 e- || The electrons are lead to the external circuit - electrolysis 4 H+ + 4 e- + O2 -> 2 H2O + heat || The circle is complete, the water can be lead to be electrolysed again Now that all works out, you have an infinite circle with no particular use. Or do you? Where the protons, electrons and oxygen reunite into water, heat is produced. Thus you have infinite heat. Not possible, I'd think. What am I missing?