gee, such hostility ... obviously i meant electrolysis ...
https://www.energy.gov/eere/fuelcells/hydrogen-production-electrolysis
https://www.google.com/search?q=water+electricity+hydrogen+oxygen
Sorry, I was grouchy. I had been arguing facts vs feelings in another forum and my fuse was short. I am sure you meant electrolysis and not the hair removal kind. ;-)
Actually the article addressed O2 production. They claim 5% of the hydrogen produced would be enough to power all O2 production required so it would just be the capital outlay for the O2 plant. I looked at cost and O2 plants don’t look particularly capital intensive. I think the bigger cost would be compressing and storing the hydrogen hence my suggestion for producing electricity from it very close to where it would be produced. IMHO it would only make sense in tar sands and tapped out fields because oil and natural gas are king and queen of easily transportable BTU’s with coal being prince.