In 2021, the Grohnde nuclear power plant in Lower Saxony on the Weser River was shut down. Now, immediately next to it, the Emmerthal energy cluster is growing with three very large battery storage systems, ground-mounted photovoltaic systems, and a new substation for several 380-kilovolt high-voltage lines.
Personally, for long term storage, I’m more a fan of simple solutions because they scale better, such as using the excess electricity to pump water up a hill, then using generators in the winter to convert it back to electricity (pumped storage).
Unfortunately, the potential for pumped hydro storage is very small in Germany :/
Not sure if that’s a problem though, the German power grid is connected to many European countries including France, Switzerland and Austria.