tdgeek:
Is H inefficient? Doesnt seem so at https://futureofworking.com/10-advantages-and-disadvantages-of-hydrogen-fuel-cells/
The simple chemistry of electrolysing water into hydrogen is wasteful, H2O into H2 and O, H2 ( which you use) had 4 electrons, O( which is lost as 02) has 8 electrons, you are keeping the smallest part of the reaction....