In particular, the optimum solution for a steady supply of renewable power for Germany (from https://model.energy) for their current average grid power demand would involve about 0.1% of this as hydrogen storage.
And that's just salt caverns. Hydrogen can also be stored in aquifers and spent oil fields.
So why is Germany building NEW pipelines from Russia to import their natural gas? It sounds like there's no point in investing in natural gas when you could spend those same billions just building hydrogen storage. What are they missing?
The cost of CO2 is not yet high enough to make the CO2-free alternative less expensive. This is the same reason Germany's coal use didn't start rapidly declining until recently, when the European CO2 market was tweaked to raise the price of CO2 credits. It's not because the CO2-free alternatives aren't possible.
(It's also possible they're adding pipelines for security reasons, to avoid cutoff by intermediaries. I don't know if that's actually the case though.)
And that's just salt caverns. Hydrogen can also be stored in aquifers and spent oil fields.