> grid... grid-scale power storage... stability of the grid ... grid-following inverter ... grid stabilized by ...

The problem isnt solar, or wind, or storage ... the problem is the grid. Were running on a system that was never designed to do what were asking of it, and yes its going to be a number of problems to solve. All of those are jobs, economic action and improvements to reliability and quality across the board.

> I don't think they're controllable enough to be mechanically synced to the grid frequency.

Google, there are a number of ways this gets addressed.

> There has been some work on grid-forming inverters

Yes, we know how, and the race to build them is on... this isnt a hard problem it's just a problem.

> grid-scale power storage (has never been done so ?

Already deployed in a few places with battery systems (hati, Australia both have them. Possibly Hawaii too). We're doing quite a bit of this. Again a quick google will give you a sea of sources.