Two million solar power storage units on the grid

06.05.2025

Source: E & M powernews

The German Solar Industry Association (BSW) reports the two millionth solar energy storage system in Germany. It calls for more speed in improving the legal framework.

According to the German Solar Industry Association (BSW), the two millionth solar power storage system was recently put into operation in Germany. This means that the storage capacity of all stationary batteries has exceeded 20 million kWh for the first time. This capacity is sufficient to cover the average daily electricity demand of two to four million two-person households - depending on the degree of electrification.

Around 600,000 new solar batteries were installed in 2024. According to BSW estimates, over 1.7 million kWh of storage capacity was added in the first quarter of 2025 alone. This corresponds to an increase of around 16 percent compared to the same period last year. The association published the figures in the run-up to The smarter E Europe energy trade fair, which is expecting more than 110,000 trade visitors in Munich from May 7 to 9.

Home storage as standard

According to BSW-Solar, home storage systems are now standard for new solar installations on single-family homes. However, the demand for large-scale storage systems in the megawatt output range is also growing. These systems are increasingly being used alongside wind and solar parks and help to buffer weather-related feed-in fluctuations. In addition to the time-shifted use of solar and wind power, they can reduce grid bottlenecks and thus reduce the need for grid expansion - provided they are intelligently controlled.

BSW Managing Director Carsten Körnig emphasizes the importance of electricity storage systems for security of supply: "Battery storage systems are already making an important contribution to stabilizing the electricity system." However, in order to further accelerate the ramp-up, a comprehensive removal of regulatory hurdles is necessary.

Specific BSW demands

Above all, Körnig is calling for battery storage systems to be quickly granted privileges under building law and for clear economic incentives. He believes that the current legal framework is no longer up to date. The specific functions of battery storage systems are hardly taken into account in current energy law, in the connection conditions of grid operators and in the regulation of the Federal Network Agency.

According to the association, the governing parties CDU/CSU and SPD have also recognized the importance of electricity storage systems. Although flexible market access for storage systems was agreed in the "Electricity Peak Act" passed together with the Greens at the beginning of 2025, its concrete implementation is still pending. The BSW is therefore pushing for this law to be applied in the near future.

The association is also calling for the simplification and reduction of connection conditions, grid fees and connection costs in order to enable the expansion of storage technologies in a way that benefits the grid and system.
According to Fraunhofer calculations on transformation scenarios in the study "Paths to a climate-neutral energy system", the capacity of battery storage systems, including mobile batteries, would have to increase to 100 to 150 million kWh by 2030.

Home storage systems are already economical

There are now solar power storage systems that yield more than they cost. The Baden-Württemberg Solar Cluster points this out. The rule of thumb: if a solar power storage system costs less than 600 to 650 euros/kWh storage capacity, it can be economical. There are already products on the market that cost less than this amount. Experts advise that the guarantee should be 15 years.

As they increase the profit of the photovoltaic system, batteries will be an integral part of a solar system in the future, explained Andreas Schlumberger from Solar Cluster. "If you also use a dynamic electricity tariff, the financial surplus can even increase," he explained. Rooftop PV systems generate climate-neutral solar power and have long been financially worthwhile. At 10 to 13 cents/kWh, electricity from a new rooftop solar system costs only around a third of the price of electricity from the socket.

So if you use your own solar power, you save double-digit cents per kilowatt hour. Battery storage systems help to increase self-consumption. This is particularly interesting as the other source of income, the feed-in tariff, is only just under 8 cents/kWh for new systems and usually does not cover costs.

Author: Susanne Harmsen