These gigafactories are in a race and those who fail will quickly get replaced by another electrolyser technology, production method or whatever. The Chinese will then buy up the IP and perfect whatever works, and the cycle will continue.
I can guarantee: it will be like solar manufacturing in the past, with all it's pitfalls and market/policy based competition.
If you type in "AEM electrolysis" in the Norwegian funded (anti) hydrogen rag, 'Hydrogen Insight' you will see that governments are now starting massive investment in new electrolyser tech of their own.
The game is over for slow ramping or PGM-dependent electrolysis manufacturers.
Governments will eventually see past the entrenched fossil-sponsored hydrogen lobbying and start investing in this truly gamechanging industry as the EU H2 pipeline infrastructure builds out and secure markets for offtakers are established - all within the (legally binding) conversion of the entire EU gas network.
Scary for some, but this is going to happen.
I'm not sure how that got on - it was from 2021 - but something like that could be interesting. The stored product is aluminium metal and gets oxidised to hydrogen and aluminium hydroxide producing heat which can be used for heating and hydrogen that can be used in fuel cells or industrial processes.
- The process must take a liquid electrolyte with two electrodes in it and a current applied, and emit some substances (I'm going to say "products") at anode and cathode which can be stored
- The process must be reversible with reasonable efficiency
- The electrodes must have a reasonable capital cost (i.e. not platinum) and lifetime (problem for exotic materials)
- same for any required proton exchange membrane (these are expensive and have finite lifetime)
- The products must be storeable, that is shelf-stable in tanks. This also means they must be fluids at room temperature; processes which emit solids are used in battery cells instead
- The products must be capable of being handled with standard plumbing, nothing weirder than stainless steel and rubber seals (may be a problem for hydrogen)
- Gas products must not be toxic (this is a big objection to using ammonia)
- Liquid products must be within the range of normally handle-able toxic substances which can be dealt with by dilution (e.g. conc sodium hydroxide is used in households, but some substance which can poison an aquifer if it leaks would be unacceptable)
- products should not be too explosive (risk for hydrogen) or react too violently on contact with air or, ideally, water
That is, it should be possible to build a system of electrolysers and tanks which is not significantly more expensive than a brewery or petrol station and, crucially, doesn't require spending too much on safety or trained personnel or insurance, doesn't require exceptional planning permission, which can be run intermittently (i.e. cheap enough that amortized capital costs are less then operating income) to store and release electricity.
Design one of those and you could be a global hero.