> because while those big generators can't move fast, demand can move fast! Which is a difficult problem to manage in baseload grids.
Don't forget rotational inertia. This gives the system a high-frequency response mode: it can resist sudden demand changes through stored kinetic energy, effectively acting as a low-pass filter with a fast dominant pole.
As you get a smaller share of generation with rotational inertia, you need a lot more buffering on short to medium timescales.
And, of course, it doesn't help for longer timescales that in many places renewable production slopes off in the late afternoon right when demand slopes upwards for cooling.
