Ancillary Services

Network Reserve

The purpose of the network reserve is to maintain generating capacities to guarantee the safety and reliability of the electricity supply system.


According to the German regulation on reserve power plants ("Netzreserveverordnung"), German transmission system operators jointly proceed an annual system analysis that includes a consideration of the guaranteed generating capacities available for demand-relevant periods within the following years. 

The system analysis indicates the total reserve demand for a safe and reliable operation of the electricity supply system. 

The comparison of the entire reserve demand with the reserve capacities that are already available results in an additional demand for network reserves for the respective time period in question.

Call for expressions of interest 

In accordance with the provisions of the German regulation on network reserve of power plants (Netzreserveverordnung) as last amended on 13th May 2019, the German national regulatory authority (Bundesnetzagentur, NRA) has examined the requirement for additional reserve power for the network reserve as determined by the German transmission system operators for the winter period 2022/2023, and has published the associated report in accordance with § 3 para 1 NetzResV.

In the report of the German NRA dated 29th April 2022, an additional demand for generation capacity for the network reserve in the total amount of 1424 MW is determined for the winter term 2022/2023, for the coverage of which an expression of interest pursuant to §4 NetzResV is initially launched. The total amount of network reserve capacity to be acquired may change depending on the sensitivity to network congestions and has to been evaluated in the context of possible alternatives within the congestion management as well as the current political situation.

The German transmission system operators hereby invite interested power plant operators to submit expressions of interest in accordance with § 4 (2) NetzResV for the participation of their power plants in the network reserve in the period from 2nd May 2022 to 15th May 2022. To submit an expression of interest, interested operators are required to complete the documents (DE & EN) supplied for this purpose and return send them to the responsible transmission system operator, both electronically and in printed form.

  • for Germany: the relevant connecting transmission system operator
  • for Italy and Switzerland: TransnetBW GmbH
  • for France and Luxemburg: Amprion GmbH

Details of the specific prerequisites and requirements for the plants and/or plant operators, including the geographical network region in question and the technical parameters involved, are included in the documents provided.

The deadline for submitting expressions of interest for participation in the network reserve is 15th May 2022. The electronic submission of the signed documents is relevant for the on-time submission.

Possible resulting contracts will depend on approval by the German NRA, especially regarding the selection of plant operators to be contracted and resulting financial obligations upon the responsible transmission system operator. There is no legal entitlement to conclude a contract.

TransnetBW reserves the right to change the published information without further announcements.

Please send your expressions of interest to be submitted to TransnetBW to

Concluded calls for expressions of interest 

Start-up tests of reserve power plants

To ensure operational readiness for necessary system security measures at any time, start-up tests of reserve power plants in Germany have to be carried out on a regular basis due to technical reasons. If possible, these tests will be integrated in necessary system security measures. Otherwise, the related energy will be brought to the intraday market. The following table provides further information on scheduled start-up tests.

In case a start-up test is cancelled, power and energy is set to zero.

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Activation of reserve power outside of Germany

To ensure security of the electricity system TransnetBW GmbH will activate network reserve power from abroad during the following time periods in coordination with the other German Transmission System Operators.

This may lead to restrictions regarding the allocation of cross-border transmission capacity at the border Germany- Switzerland.

Note to table: If an upcoming activation of reserve power from outside of Germany has already been published, but has not been used (cancellation), the end date is set equal to the start time.

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