The battery storage market is currently experiencing dynamic development, with a lot of projects being planned, built or expanded. The idea behind publishing these figures is to increase transparency and enable a better understanding of developments with regard to battery storage. These figures for the first time include data on connection applications at the distribution system operator level, for which no detailed information had previously been available. These new analyses give a full overview of the current situation regarding planned battery storage projects in Germany. The information is based on figures from the latest monitoring survey and, due to system constraints, is only available for 2024. Information on developments in 2025 will be published in due course.

Current situation regarding battery storage connection applications and approvals

According to the figures reported by the network operators in the monitoring survey, a total of 9,710 connection applications for battery storage facilities at or above medium-voltage level were made in 2024. This figure does not include domestic battery storage facilities. The facilities for which applications were made have a combined planned capacity of around 400 gigawatts (GW) and a storage capacity of around 661 gigawatt hours (GWh).

In 2024, an additional 4,200 or so applications were being assessed for battery storage facilities with a total planned capacity of around 274 GW and a storage capacity of around 326 GWh. Both the number of applications being assessed and the number of applications that have already been approved include applications made before 2024 and should therefore be looked at separately.
Good to know: The 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 on the tap. The storage capacity in gigawatt hours tells you how much energy a facility can store overall – like the size of a water tank. The larger the capacity, the faster a facility can supply electricity, while the larger the storage capacity, the longer the facility can supply electricity.

It must 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; this means it is likely that a large proportion of applications will not actually result in a project being implemented.

Whether or not a battery storage facility can be connected to a network depends on various factors, including the technical connection requirements, the available network capacity and the outcome of the network compatibility assessment by the network operator responsible. As the approval of an application also constitutes an offer to conclude a connection agreement, the number of approved applications gives a better picture of how likely it is that projects will be implemented. Nevertheless, an approval does not necessarily mean implementation, as connection approvals are only binding for the network operators. In 2024 around 3,800 applications were approved. The facilities for which connection was approved have a combined capacity of around 25 GW and a storage capacity of around 46 GWh.

The following charts show a breakdown of the applications and approvals between transmission and distribution system operators:

By comparison: According to the core energy market data register, 921 operational battery storage facilities are currently connected at or above medium-voltage level. These facilities have a net rated capacity of around 2.3 GW and a storage capacity of around 3.2 GWh. If just all the projects for which connection was approved in 2024 were implemented, there would be an increase several times over compared with the current situation.

Practical classification of battery storage capacity

Let’s have a look at a couple of examples to see what these figures actually mean.
The average German household has a continuous load of about 0.4 kW (≈ 3,500 kWh/8,760 h). The battery storage facilities for which connection has already been approved have a total capacity of 46 GWh; this means they could meet the demand for electricity in the whole of Munich – around 750,000 households – for about six days (750,000 × 0.4 kW = 300 MW → 46 GWh/0.3 GW ≈ 153 h ≈ 6.4 days).

Battery storage during solar peaks

We can see just how much storage facilities can help the situation in the electricity system on days when there is an unusually high level of generation from renewables. The highest level of solar generation in Germany in 2024 was recorded between 1pm and 2pm on 29 July – around 47 GWh of electricity.

Between 10am and 5pm the amount of electricity produced from all sources in Germany was more than the country’s grid load (the total amount of electricity consumed). The share of total generation from solar photovoltaics (PV) during this time was particularly high: on average solar generation covered around 69% of Germany’s grid load.
 

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During those hours, the demand for electricity in the country was smaller than the amount of electricity being produced. The result: wholesale prices for electricity dropped considerably – and were negative in five out of those seven hours. This meant some electricity producers had to pay in order to be able to market their electricity. This is because of the interplay between supply and demand on the electricity exchange: if too much electricity is generated and not enough is used, prices will fall – sometimes to below zero, which will then boost demand and bring generation and consumption back into balance.

If we look at the battery storage facilities that have already been approved for connection, with their total capacity of around 46 GWh, we get an idea of the potential of battery storage. If all those storage facilities had been operational and integrated into the electricity grid, they could have stored about 76% of the electricity produced that was surplus to Germany’s demand on that day. If we have a look at just the hours when prices were negative (between 11am and 4pm), the facilities could have stored as much as around 86% of the surplus electricity.

The wholesale price for electricity between 1pm and 2pm was negative €2 per megawatt hour (MWh). A simplified model calculation with strong assumptions shows that if the battery storage facilities had stored energy when prices were negative, just one fifth of their storage capacity – about 5 GW – would have been enough to push the prices up to about €75/MWh in that hour.

Battery storage during dunkelflaute periods

We can also get an idea of the potential of battery storage when the situation is the complete opposite – on days with a low level of generation from renewables and a large increase in prices.

The highest day-ahead price for electricity in 2024 was recorded on 12 December. Between 3pm and 7pm – the hours in the afternoon and evening when consumption is typically high – the level of generation from renewables was particularly low. As a result, electricity prices rose significantly to above €600/MWh. Between 6pm and 7pm they even reached €936 /MWh.
 

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The total difference between the amounts of electricity generated and consumed in Germany during that period was 57.7 GWh, which had to be covered with imports. If the battery storage facilities that have been approved for connection had been full at that time and had supplied electricity, their storage capacity of 46 GWh could have covered around 80% of that difference between generation and consumption.

An analysis of the aggregated bids on EPEX Spot shows that an additional flexibility of just a few gigawatts in the hour when electricity cost €936/MWh would have been enough to bring down the price considerably – by several hundred euros per megawatt hour. If a fifth of the battery storage facilities approved for connection, with a combined capacity of 5 GW, supplied electricity when prices are €100/MWh or more, the price in that hour – given the same conditions such as an unchanged demand curve, a lack of responses in the market and no cross-border effects from market coupling – would have fallen to about €160/MWh.

Impact on electricity prices and the overall system

If the storage facilities that the network operators have already approved for connection were actually operational in the grid, the number and length of phases with negative electricity prices could be cut significantly. This is because battery storage facilities respond to price signals: they store electricity when prices are low (when generation is high and consumption is low) and supply electricity when prices rise again.

This arbitrage trading pushes up demand when generation is high – in particular from renewables such as solar PV. The amounts of energy that are stored increase the load on the networks but counteract surplus generation from renewables and the need to curtail renewable generation due to a lack of demand. Storage facilities stabilise prices by making the difference between generation and consumption smaller.

Later on in the day, when renewables produce less electricity, storage facilities can feed back the energy they have stored into the grid. They can therefore make an important contribution, especially during dunkelflaute periods when low levels of electricity generation from wind and solar coincide: when storage facilities feed electricity back into the grid when prices are high, they are providing an extra supply of electricity, which dampens extreme price peaks and stabilises supply. In this way, battery storage facilities contribute to both security of supply and price stability, while supporting the efficient integration of solar and wind power into the energy system.