Method for dimensioning of the demand for automatic and manuell frequency restoration reserve (aFRR and mFRR)

The demands of aFRR and mFRR are jointly dimensioned by all four German TSOs for the German grid area. A probability-based approach is used. Therefore the probability of imbalances is taken into account for the respective dimensioning period. The result corresponds to the dimensioning for the joint provision of aFRR and mFRR of the German Grid Control Cooperation.

Beginning with the 9th December 2019 (10th December 2019 delivery day) dimensioning is no longer performed quarterly for the following quarter but individually for each 4-h product. The historical system imbalances are the basis for the dimensioning. Power plant failures are subtracted out of this basis and taken into account via a failure probability of the power plant park. The basis is formed by the statistical failure probability of the individual power plant types. All power plants with a rated power of 100 MW or more are taken into account. In principle, the following input variables are taken into account to classify the input data:

  • time of the day
  • date
  • month
  • day of the week
  • day type (holidays, bridge days or days with special events)

A detailed description of the dimensioning method can be found in the expert report on the dynamic dimensioning method. This is published on The new method will lead to a dynamic demand fluctuating between sequential products and / or days. The TSO will introduce the new method stepwise to allow market participants sufficient time for adaption.

Determination of the required primary control reserve

The primary control reserve or frequency containment reserve (PCR/FCR) to be maintained under the German grid control cooperation is agreed annually between the transmission system operators (TSOs) of continental Europe. It is based on a total need of ±3000 MW PCR for the synchronous area, divided among the TSOs in proportion to the yearly feed-in and consumption.

Detailed information is available in Annex 1 of the Synchronous Area Framework Agreement for Regional Group Continental Europe. This is published on Entso-E Transparency Platform.

Overview of the historical reasons for changes in the required control reserve as of 2012