Energy storage
Battery storage
Storage energy capacity
The total stock and monthly additions of battery storage systems in Germany are shown below. The data is based on the Market Master Data Register (MaStR) of the Federal Network Agency. The preparation and categorization into home, commercial and large-scale storage systems largely follows the methodology of the Battery Charts of RWTH Aachen University. Home storage systems are currently mainly used to optimize the self-consumption of PV systems (prosumers), but not for arbitrage in the electricity market. The same is likely to apply to larger industrial storage systems. A significant proportion of large-scale storage systems are likely to be active primarily in the balancing power market. Home storage capacity has recently grown strongly in parallel with the strong growth in rooftop photovoltaics (see Deep dive photovoltaics). The flattening of the expansion at the current margin is due to incomplete data and is likely to change as a result of subsequent reports.
Storage power
Due to the typical dimensioning of the batteries, the picture for the cumulative battery power rating is very similar to that for energy capacity.
Pumped hydro storage plants
Storage energy capacity
Pumped hydro storage plants have been in use for decades and are still the most relevant large-scale electricity storage systems in Germany. However, their capacity has stagnated in recent years, while battery storage has recently grown strongly (see above). The last major addition in Germany was the Goldisthal pumped hydro storage plant in 2004. The pumped storage facilities installed in Germany mostly have artificial upper reservoirs without a natural inflow. The figure also shows pumped storage power plants in Austria and Luxembourg, which are directly connected to the German transmission grid and are therefore also included in the Federal Network Agency's Market Master Data Register (MaStR), which forms the data basis for the figures shown here. The total installed energy storage capacity of pumped storage in Germany is currently a good 35 GWh, plus 19 GWh in Austria and Luxembourg, making a total of 54 GWh.
Storage power
The installed power rating of pumped hydro storage plants has developed similarly to their storage capacity. The plants installed in Germany have a total capacity of just over 6 GW, plus almost 4 GW abroad, i.e. a total of almost 10 GW.