That's the best that PEM electrolysis can do. Solid oxide cells have been >93% efficient for over a decade now, and some research cells are 99% efficient. If yo

That's the best that PEM electrolysis can do. Solid oxide cells have been >93% efficient for over a decade now, and some research cells are 99% efficient. If you are willing to supply heat to run in endothermic mode, they are >100% efficient on an electricity basis (meaning they take less than 39kwh of electricity to make a kg of hydrogen, with the rest made up via heat). I personally have made hydrogen with SOECs for $2.72/kg using industrial rates for electricity. After a 60% efficient conversion back to electricity, that comes out to $0.116/kWh, which is better than the residential rates for nearly any state.