In other cases, storage facilities optimise consumption or the feed-in of renewable energies and thus help to keep costs down on the consumer side and to improve the integration of renewable energy.

The most recent data collection shows that the market for commercial grid-scale battery storage from the medium-voltage level upwards
(not including domestic battery storage) is continuing to develop.

Current situation of battery storage connection applications and offers

The battery storage market is undergoing a period of dynamic development characterised by intensive planning, construction and expansion. For the second year running, the data from transmission and distribution system operators provided on the basis of the Bundesnetzagentur’s monitoring survey offers insights into battery storage connection applications. It is now possible, for the first time, to directly compare the data from that of the previous year, illustrating ongoing developments.

The data available has not so far distinguished between grid-connected and co-located storage facilities. The Bundesnetzagentur will make it possible to differentiate between the two types in future.

The direct comparison with the data from 2024 highlights the enormous growth in the number, volume and energy capacity of network connection requests for battery storage facilities. Project developers are increasingly securing potential locations.

• Network connection applications: a total of 18,158 requests, an increase of 194%, were received across the entire network in 2025. These applications covered a combined power capacity of about 573.5 gigawatts (GW), equivalent to growth of 43%, and energy capacity of around 1,583 gigawatt hours (GWh; +139%).
  
  It should be noted that some of the applications made are for the same projects. In many cases, project developers make several applications for connection at different potential locations to increase their chances of success. If more than one application is approved for a project, however, the project developer will usually only choose one location.
  
   
• Connection offers: network connection offers provide a more realistic picture of the actual implementation progress as they are binding offers to conclude a connection agreement. The total number of connection offers in the entire network, including those relating to applications from the previous year, was 1,937 in 2025 (up 55%).
  
   
• Power and energy capacity in network connection offers: the offers covered 54.2 GW of power capacity in the entire network (up 119%) and 142.4 GWh of energy capacity (up 207%).
  
  For comparison: there are currently 28 pumped storage power stations with an installed power of about 6.2 GW and an energy capacity of about 147 GWh in operation in Germany. If the batteries that have received offers were fully implemented and available on the market, the short-term flexible power capacity in the electricity system would multiply to 54.2 GW compared to the current pumped storage available. The additional energy capacity of 142.4 GWh would correspond to almost the existing German pumped storage capacity.

Good to know: the power capacity in gigawatts tells you how much electricity can flow into or out of a battery storage facility at any one time – a bit like how fast water can flow out of a tap, depending on how far you turn it on. The energy capacity in gigawatt hours tells you how much energy a facility can store overall – like the size of a water tank. The larger the power capacity, the faster a facility can supply electricity, while the larger the energy capacity, the longer the facility can supply electricity.

Status quo 2025: distribution system vs transmission system

The integration of battery storage is not divided equally between distribution system operators (DSOs) and transmission system operators (TSOs). While DSOs manage the majority of projects by number, TSOs have major individual projects at the extra-high voltage level. For the TSOs, the average power capacity of an approved network connection application for a battery storage facility is about 384 MW, whereas in the distribution systems it is about 14 MW (average energy capacity 841 MWh for TSOs and 44 MWh for DSOs).

This could be due to the fact that grid-connected (stand-alone) storage facilities tend to be connected to the transmission system while co-located storage facilities are, naturally, usually connected to the distribution system.

Distribution system

Most battery storage projects are requested at the regional level.

• Network connection applications in 2025: 17,775 applications with power capacity of about 406.8 GW and about 1,185.9 GWh of energy capacity.
• Connection offers for applications made in 2025: offers were made for 1,429 of these applications (16.8 GW/59.2 GWh), so the proportion of connection applications for which offers were made was about 8%.
• Total connection offers in 2025: the DSOs made a total of 1,866 offers in 2025, including those from older applications, with power capacity of 26.9 GW and energy capacity of about 82.7 GWh. The average storage capacity was thus around 44 MWh.

Transmission system

The following battery storage projects were requested and approved directly to the transmission system in 2025.

• Network connection applications in 2025: 383 applications with a planned power capacity of about 166.7 GW and an energy capacity of about 396.8 GWh.
• Connection offers for applications made in 2025: offers were made for 39 of these applications (17.2 GW/39.6 GWh), so the proportion of connection applications for which offers were made was about 10%.
• Total connection offers in 2025: the TSOs made a total of 71 offers in 2025, including those from older applications, with power capacity of approximately 27.3 GW and energy capacity of about 59.7 GWh. The average energy capacity of the applications was thus around 841 MWh.

Distribution of network connection applications and offers in 2025 (TSOs and DSOs)

The battery storage projects for which applications and offers were made in 2025 were divided between the German transmission and distribution systems as shown below. The following data refers only to applications newly received by the network operators in 2025. Applications and data from previous years are not included in this evaluation.

In the distribution systems in 2025, offers could be made for just 8% of the connection applications received, which only corresponds to about 4% of the power capacity applied for. In the transmission system, offers were made for about 10% of applications, which was also about 10% of power capacity applied for.

To compare: according to the core energy market data register, 1,292 operational battery storage facilities are currently connected at or above medium-voltage level. These facilities have a net power rating of around 3.6 GW and an energy capacity of around 6 GWh. If just all the projects applied for and for which offers were made in 2025 were implemented, there would be an increase several times over compared with the current situation.

Look ahead to 2026: dynamic developments to continue in the extra-high voltage network

A look at the TSO figures for 1 April 2026 shows that there is a sustained interest in grid-scale battery storage.

• New network connection applications (as at 1 April): 23 connection applications were received by the TSOs in the first months of this year, comprising a planned connection power capacity of about 6.0 GW and an energy capacity of about 16.4 GWh.
• Processing of connection applications from 2025 (as at1 April): another 10 offers had been made for applications submitted in 2025 by 1 April 2026. They had a combined power capacity of about 3.9 GW and energy capacity of about 9.3 GWh.
• Total connection offers in 2026 (as at 1 April): the TSOs have already made 64 offers in 2026, including those from older applications, with a total power capacity of approximately 24.7 GW and energy capacity of about 55.4 GWh.

That means that the TSOs have made connection offers in the first months of 2026 up to 1 April comprising nearly as much volume as in the whole of 2025.

Summary and energy industry context

The statistics show a functional division in the energy system. While the decentralised transformation is taking place across the country in the distribution system, a series of very large battery storage facilities is taking shape in the transmission system.
Batteries can help to balance the electricity market by, for example, flexibly offsetting the large amount of solar power produced on sunny days. When production exceeds demand, these storage facilities can smooth off the peaks as they respond to market signals and provide economic incentives for charging and discharging depending on the market situation at the time. This prevents strongly negative prices occurring or the network coming under strain in situations when there is far more electricity being produced than consumed. There were negative prices in 573 hours (6.5%) in 2025. The balancing effect of battery storage helps to make use of renewable electricity at all times and thus also contributes to reducing the burden on the renewables account in the federal budget.

Note: the 2024 figures have been updated and are thus not identical with those published in last year’s article.