Determination of the demand for secondary control reserve and minute reserve
The secondary control reserve and minute reserve to be held in reserve is dimensioned jointly by all four German TSOs for the German grid area. A probability-based approach is used, which takes into account the probability of imbalances in the respective dimensioning period to be dimensioned. The result corresponds to the dimensioning for the German network control area (NRV).
As of 09.12.2019 (delivery date 10.12.19), dimensioning is no longer carried out quarterly for the respective following quarter, but individually for each 4-h product. The historical system imbalances form the basis. Power plant outages are deducted from this basis and taken into account via an outage probability of the power plant fleet. The basis is the statistical failure probability of the individual power plant types. All power plants with a capacity of 100 MW or more are taken into account. Basically, the following input variables are taken into account for the classification of the input data:
- time of the day
- day of the week
- day type (holidays, bridge days or days with special events)
Details on the dimensioning procedure can be found in the expert opinion on dynamic dimensioning. Dynamic sizing results in volatile demands between successive time slices or days. The TSOs have introduced the procedure gradually in order to give all market players sufficient time to adapt. The dimensioning procedure has been fully implemented since 03.10.2020 (provision day).