hydrogen is terrible
https://forums.theregister.co.uk/forum/1/2018/02/21/contisol_solar_reactor/
Comment by Charlie Clark
Hydrogen is a terrible way to store energy anyway, despite initial high
hopes. It's super dangerous (I work in a lab that uses it), explodes in
any mixture with air, embrittles metals, is hard to store any quantity of
in a small space as would be needed for cars.. and when burned, say in an
IC engine, is no better than gasoline re thermodynamic efficiency. Fuel
cells need catalysts that are in far too short supply to make enough cars
to serve a single US state.
Truth hurts, but there it is. Batteries long ago became better than
hydrogen systems, and are a lot safer.
Nature's way of storing hydrogen is hydrocarbons. Works really well, we
use them because of that - too bad they also have carbon that's going to
burn too and make pollution...but nothing else works for storing energy
quite so well.
I'm a scientist and I eat my own dogfood, living off the grid since long
before it was cost effective (solar was $6 a watt when I started).
Hydrogen like my lab uses in fusion research, is pretty nasty stuff if
you get a leak, and it's about the second leakiest substance on earth
after helium. The tiniest leak in a hose gives you instant flame even in
a non sparking environment room. If you're lucky, it's right away, and
not an explosion after a little more leaks and mixes with air.