In theory, but not in practice, captive hydrogen can be made by exergy capture using thermochemical cycles. General Atomics in the US explored this in the 1960's and 1970's, and recently, if I recall correctly, the Chinese explored the SI cycle on their HTGC-10 reactor.
If however, someone makes hydrogen using electricity using the thermodynamically and economically unviable process of electrolysis, unless a grid is 100% nuclear, which no grids on this planet are, not even France, than one is simply playing a shell game, wasting electricity electrolysis of water while burning fossil fuels to make up the difference elsewhere.
I analyzed the details along these lines elsewhere:
A Giant Climate Lie: When they're selling hydrogen, what they're really selling is fossil fuels.
Electricity is thermodynamically degraded and making hydrogen from it degrades it even further. Even if the mythical "green hydrogen" existed on any scale - it doesn't - it would be a very, very, very, very, very poor choice for a consumer product. It has horrible physical properties, not the least of which are extremely low viscosity and incompatibility with many metals via the well known issue of hydrogen embrittlement.
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