Con­fir­ma­tion of electricity grid re­serve capacity re­quire­ments

Year of issue 2024
Date of issue 2024.04.30

The Bundesnetzagentur has today confirmed the grid reserve capacity requirements for winter 2024/2025 and winter 2026/2027.

"Stable network operations next winter are guaranteed. The grid reserve capacity required is smaller because some network expansion projects have been completed. This reduces the need for redispatching measures, which is what the grid reserve is kept for," said Klaus Müller, President of the Bundesnetzagentur. "Old coal-fired power plants are no longer needed for the supply of electricity on the market. They are only used for a few hours in exceptional situations when necessary to stabilise network operations."

Grid reserve capacity for 2024/2025

The Bundesnetzagentur has confirmed a total required grid reserve capacity of 6,947 megawatts (MW) for winter 2024/2025.

Last winter a number of power plants in the grid reserve operated in the market on the basis of the Maintenance of Substitute Power Stations Act (EKBG). The aim was to cut down on the amount of gas used to produce electricity. The temporary return to the market by these power plants from the grid reserve meant that the amount of grid reserve capacity required last winter was mathematically smaller. The power plants have now left the market and returned to the grid reserve, which nominally increases the amount of grid reserve capacity required.

This year's required grid reserve capacity is therefore closely comparable to that for winter 2022/2023, which was 8,264 MW. The decrease in the amount of capacity required for winter 2024/2025 is due to the completion of some network expansion projects and a consistent increase in the degree of usage of existing power lines since 1 January 2023. This reduces the need for redispatching measures, which is what the grid reserve is contracted for.

As well as the requirements for the forthcoming winter, the requirements for a winter further ahead are routinely identified. For winter 2026/2027, the required grid reserve capacity has been put at 9,202 MW.

The increase in capacity is due to the anticipated increase again in electricity consumption and the required expansion of cross-border trading capacity under European regulations. Together with the progress made in the expansion of wind capacity in the north of Germany and the construction of large-scale ground-mounted solar photovoltaic systems relatively far away from demand centres, this means that it is not possible to transport all the electricity needed to regions with high consumption because of delays in network expansion.

Provision of grid reserve capacity

A total of 5,580 MW of the grid reserve capacity needed for winter 2024/2025 will be provided by German power plants. As in previous years, power plants in other countries will provide the remaining capacity of 1,367 MW (2022: 1,424 MW; 2023: 1,334 MW). The transmission system operators will ask foreign power plant operators to register their interest in providing grid reserve capacity by mid-May. The transmission system operators will then open contract negotiations in coordination with the Bundesnetzagentur.

Reserves for network stability

Grid reserve capacity is contracted to prevent overloading in the transmission system that occurs because of still insufficient progress in grid expansion. This is done by reducing generation in front of an impending congestion and at the same time increasing generation behind the congestion.

This mechanism, known as redispatching, is carried out in the first place using power plants that are active in the market. In certain situations, however, the active plant capacity is not sufficient to relieve the congestion. In such cases, additional grid reserve power plants need to be activated. The German grid reserve power plants are power plants that have been marked for closure but may not be shut down because they have been categorised as important for the system. These power plants may only be used when instructed by the transmission system operators and may not be operated in the market. The grid reserve power plants in other countries are contracted especially for this purpose. The costs for contracting and using the power plants are part of the overall redispatching costs and are refinanced through the network tariffs.

The transmission system operators presented their system analysis and the resulting grid reserve capacity requirements to the Bundesnetzagentur for evaluation on 11 March 2024. The determination of the grid reserve capacity is the final step in the Bundesnetzagentur's evaluation process.

The report (in German) has been published at www.bundesnetzagentur.de/netzreserve.