[stephengillie]

Yeah, we've got to expect the 2nd Law of Thermodynamics to come in and ruin the party.

You could power the electrolysis from solar, but then you've got transmission loss on the wires. You're right the gases are too lightweight to push more than the lightest fan turbine.

Even having the gases get separated, turn a turbine while floating up, get recombined into water, then be pulled down past another turbine by gravity, we might not get the full 1.5v back.