It's still not earning you money to spend electricity because you still have to pay the transfer fee which is around 6 cents / kWh but it's pretty damn cheap nevertheless, mostly because of the excess in wind energy.
Last winter because of a mistake it dropped down to negative 50 cents / kWh for few hours, averaging negative 20 cents for the entire day. People were literally earning money by spending electricity. Some were running electric heaters outside in the middle of the winter.
Don't store it in diatomic form. Ammonia is the common alternative for hydrogen storage and transport, iirc
And even if round trip efficiency is poor, if renewables are in excess, it would be so much better to dump that energy into something that to have to curtail.
There's no shortage of solutions better than hydrogen for storing grid energy.
There were niches where hydrogen might have made sense 10 years ago. Other solutions have gotten better and better--not just lithium batteries, either--and it's gotten squeezed out. There's still a few where it might, like trucks and planes, but even those seem to getting overtaken by better tech elsewhere.
Any significant investment in hydrogen infrastructure is likely to be overtaken before it can see a return on investment.
I agree: transportation will probably favor hydrogen over batteries.
That being said, to pile on hydrogen, I'm not sure if I like the water demand part of it either. Coastal hydrogen production might make sense if sea water is the feedstock and corrosion/discharge can be released to the source in a manner that doesn't lead to biodiversity death.
Then again, fossil fuel and mineral based (thermal) energy sources like coal, nat gas, oil, and nuclear all require cold water for cooling purposes. If we transition those sources to hydrogen production (and maybe use in the case of 100% hydrogen fired CCGTs that GE, Siemens, andbMitsubishi are making), there might actually be increased water demand since you have hydrogen + cooling.
It'll have it's niche, that's for sure. But I wouldn't count it out.
And on the topic of better solutions, I'd love to see vertical underground pumped hydro storage pick up steam (buh dum tss). I don't see how underground pumped hydro isn't feasible since we already do geothermal in the same way.
There aren't many other options for long-term storage. Massive, cryogenic storage facilities could hold summer-produced hydrogen for winter generation, or allow grid-scale energy transport across the equator.