The coal and nuclear phase outs across Europe will lead to a need for new flexible capacity. That should at least partly be covered by battery peakers.
In France and Germany, nuclear reactors are configured and permitted to run in load following mode. It's harder on the valves and similar equipment, but it can and is done. [1]
> unless the renewables become incredibly overprovisioned.
Which is the likely outcome, as solar and wind are still declining in cost and in some places the cost is as low as 2 cents/kwh. The generation will be cheap (what's the old saying? "too cheap to meter"?), and it'll be the storage that'll cost a bit more.
[1] https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-lo...