[credit_guy]

The scalable part is going to be difficult though.

This is not all that different from the production of hydrogen. Hydrogen is most economically produced from natural gas nowadays. You can produce it from water, with (just like here) an almost 100% current-to-hydrogen efficiency. But it's still twice as expensive, if not more.

[Superfluidity]

Electrolysis of water is 70–80% efficient (a 20–30% conversion loss) while steam reforming of natural gas has a thermal efficiency between 70 and 85%. https://en.m.wikipedia.org/wiki/Hydrogen_production#:~:text=....

[ororroro]

Current/Faraday efficiency is an entirely different thing. 100% current efficiency means you won't get a buildup of side products or erosion of your electrodes due to stray electrons. In isolation it is not a measure of power efficiency.