[ephbit]

> ... excess renewable energy could simply be stored for later use, ie in chemical batteries or as hydrogen.

"Simply" implies "in an economically viable fashion" here. Which means that someone has to be willing to pay for (A) building these batteries or electrolyzers and (B) operating them.

Building such systems to an industrially relevant scale hasn't really happened yet. Because it hasn't been economically viable.

Just now they're building a 30 MW electrolyzer near Leuna and it'll be the largest in Europe. Compare that to a regular powerplant which has 1 GW and you'll get an idea that large scale hydrogen synthesis isn't all that near.

Either (A) governments subsidize such systems to a great degree or (B) electricity has to be dirt cheap for a decent fraction of the year (say 50 % or 4400 hours), because if you want to run an electrolyzer, ideally you want to run it 24/7, not every second day at noon because there's cheap PV electricity.

I think (A) is more likely to happen within the next decade than (B), but even when we eventually have these electrolyzers, Bitcoin mining might still be more lucrative.