According to Section 13 (1) EnWG, the German transmission system operators with control area responsibility (TSOs) must ensure the safety and reliability of the electricity supply system in their control areas and are authorized to conclude contracts with providers of disconnectable loads for this purpose in accordance with Section 13 (6) EnWG.
The use of disconnectable loads serves to directly stabilize the system frequency and is activated in the event of an underfrequency of 49.7 Hz. The use of disconnectable loads as a substitute for automatically or manually activated control energy, as well as within the scope of redispatch, is not intended.
The activation of the disconnectable loads can be either automatic by a frequency relay or manual by a decision of the transmission system operator. In the case of automatic activation, power shall be provided within one second of activation. Manual activation shall be by an electronic polling signal or by telephone request. Automatic underfrequency disconnection is carried out as a supplementary measure to the European frequency targets with control reserve deployment and upstream of underfrequency-dependent load shedding (UFLA) as part of the ten-stage plan in accordance with the system protection plan.
The bid compensation in the invitation to tender (award price) is based exclusively on a performance price. Thus, the bid price includes the compensation for the provision and the work performed. Prequalification as a provider of disconnectable loads is required to participate in the tender.