When’s that going to happen? Right after the green hydrogen revolution?

Already happening, on a small (but industrial) scale. You can buy that stuff off the shelf, but it's still on the lower end of the sigmoid. Most new installations right now will be going to Canada and Namibia, we'll be buying massive amounts of ammonia from both.

Sorry, I didn’t think someone would deny the existance of dunkelflautes. It’s currently happening in Germany.

Yes and elsewhere in Europe the wind is blowing. Differences in solar yields are seasonal (that's what those three months storage are for, according to Fraunhofer's initial plans), but reversed on the other side of the globe, and Germany would be better situated to tank differences in local wind production all by itself if e.g. Bavaria didn't hinder wind projects in their state. The total energy the sun infuses into the earth does change a bit over time, but that's negligible. In principle pretty much zero storage is needed as long as there's good enough interconnectivity.

...meanwhile, we'll probably have the first commercial fusion plant in just about the mean construction time of a fission plant.