[robocat]

> Sweden’s SSAB, for example, is building an underground cavern, where it will store hydrogen it has created using off-peak North Sea offshore wind

I found the following information about the SSAB pilot cavern:

  The pilot plant has a size of 100 cubic meters. At a later stage, a full-scale hydrogen gas storage facility measuring 100,000 to 120,000 cubic meters may be required which is sufficient to supply a full-sized sponge iron factory for three to four days.

[0cf8612b2e1e]

The technical challenges must be greater than I imagined, because even for a pilot study, 100m3 seems very small.

[kolinko]

Anything about pressure, or total weight of hydrogen stored? Without those it’s unknown really how much energy or hydrogen they store.

[chii]

> to supply a full-sized sponge iron factory for three to four days

how long does it take to fill, because if it takes longer than 3-4 days to fill, then it's not a matter of storage capacity, but production capacity.

[TazeTSchnitzel]

I wonder how they prevent the gas in such a cavern from exploding?

[patall]

By not adding oxygen?! Hydrogen itself doesn't spontaneously explode.

[TazeTSchnitzel]

Sure, but if there's a leak you have a problem.

[patall]

Even then. Hydrogen quickly moves upwards. If it is a ground storage, any burning should happen above the storage and not enter it (at least in theory). And you can measure changes in pressure quite easily. I mean, it is not like hydrogen storage has not been done for more than 100 years.