Is this a big deal? This report mentions electrolyzers hitting 80-95% efficiency back in 2004: https://www.nrel.gov/docs/fy04osti/36705.pdf
The big H2 inefficiencies are still the compression, transportation, and conversion back to electricity.
The big H2 inefficiencies are still the compression, transportation, and conversion back to electricity.
Something like direct butanol synthesis and fuel cells would be the ultimate I think, a liquid fuel that could be burned as jet fuel as well as in a fuel cell.
Edit: my time frame is off, I'm bad at estimating elapsed time in general. So we are probably a ways off from commercialization.