Is it an excellent large-scale stationary energy store though?

I mean, it seems like it should be but

* Hydrogen really likes to leak.

* Hydrogen breaks down the container holding it over time.

* Hydrogen is very low density. This means you need either a very large container or very high pressure. Combined with 1 and 2 this is going to be expensive.

I'm really asking the question. I would love to know the full cost difference with current tech vs other options.

> * Hydrogen really likes to leak.

Yes, but the rate of leakage is tiny enough that for any reasonable sized tank it's going to be years till it's all leaked away.

The real risk is the leakage causing explosions if you ever put a tank in a confined space.

It leaks a lot faster if it corrodes a hole in the container. Hydrogen is fairly reactive.

That's probably only the 'primary' real risk, there are some number of secondary real risks of hydrogen being a very reactive chemical. Not in the flammable boom boom, but the interacting with stuff it shouldn't and causing degradation and corrosion.