There's occasionally overproduction of renewables, which is normally just curtailed (discarded) because it exceeds grid demand.
The H2 for medium-term tank storage idea is not bad .. except for the very high capital cost of electrolysis. Without some means of making H2 that doesn't involve tying up a chunk of platinum as a capital asset this is a non starter economically.
Batteries are as yet inappropriate for long duration swings over weeks or months that cycle only a few times a year.
Better to compare it to thermal storage, PHES, simply curtailing it or even virtual storage via hydro or w2e (or hydrogen generation with no step where it is converted back to electricity or motion). All of which are more sensible than hydrogen for personal transport.
Why is that better than putting it back into the grid and/or putting it into a battery?