Large Inverter Based Resources (IBR) such as huge solar parcs, grid-scale batteries or high-voltage direct-current (HVDC) lines can be programmed to behave like rotating generators, or even to smooth out smaller ripples. They also don't necessarily need a leading grid frequency but can be used to generate their own frequency normal to cold-start or resync a grid.
replyOnly "small stuff" IBRs need a leading frequency from the grid and disconnect outside their safety corridor because those usually aren't controllable from some central grid authority. Thus the stupid-but-safe behaviour mandated for them.
While this is plausible, this solution works in the world of simulations.
replyWe do not have a solid understanding of how inverter-based fast frequency response works with an existing grid that uses physics-based inertia.
What about large scale distributed containerised Iron Salt batteries?
replyI've seen some papers saying that they help stabilise grids.