Cannot find a graph of battery capacity growth for Germany right away, but anecdotally (stories in the news and number of startups I‘m aware of), that market is super hot right now.
Edit: according to [1], numbers predict a coming tsunami of battery installations for Germany
Battery capacity in Germany is growing exponentially, but most batteries being installed right now are home systems that don't help much to stabilize the grid.
If consumers can get up-to-the-minute pricing, they can. It's not uncommon to charge at night and discharge during the day if you're on such a system and it saves you money.
Edit: according to [1], numbers predict a coming tsunami of battery installations for Germany
[1] https://www.pv-magazine.de/2025/01/13/uebertragungsnetzbetre...