It's less about the difficulty of the process, more about efficiencies. I don't have time to find numbers, but I believe it's a pretty lossy process to split water, and then turn it back into electricity in a fuel cell type device.
There are also (probably) a lot of costs involved with trying to contain the hydrogen, and making and industrial sized fuel cells. Maybe quite a few unsolved problems as well e.g. do fuel cells eventually wear our like batteries?
Basically, we could do it, but the current techniques are possibly more expensive and too lossy compared to other options, like molten salt, pumped hydro etc.
> trivial to turn water into hydrogen via electrolysis
The platinum catalyst is expensive, and as others point out, you need special piping for hydrogen.
More promising is direct ammonia synthesis: https://www.chemistryworld.com/features/ammonia-synthesis-go...
Re:Hydrogen’s moment is here at last?
by abdupattoh on Sunday October 10, 2021 @02:16AM
(#28816207)
The Middle East / GCC oil countries are looking seriously into ammonia as energy transport to Europe for blue hydrogen. (produced from petrocarbons with sequestering.)
The biggest problem right now is the cost of the electrolysers (they need to be cheap to be driven with intermittently available renewable power), but their cost has been coming down and should continue to come down as production scales up, just as happened with wind turbines and PV.
Why not just store excess renewable electricity that way, local to wherever that power is being generated in underground pressure vessels or something, venting the oxygen produced to the atmosphere? Then when the wind isn't blowing, or sun isn't shining, burn the hydrogen to run something resembling a conventional natural gas generator... Don't bother transporting this stuff anywhere, produce it onsite, burn it onsite. Couldn't you also capture the exhaust of the hydrogen combustion to recharge the input electrolysis water?