manual Frequency Restoration Reserve

Activation of manual Frequency Restoration Reserve

mFRR calls are processed by the system operated by the TSOs called MOLS (Merit Order List Server). The MOLS provides both the connection to the providers and to the European MARI platform for international mFRR exchange. More information about the MARI platform can be found under the section European Cooperation.

Connection to MOLS

The communication between MOLS and the provider is usually automated. Therefore, the provider needs a local tool for activation. The TSOs provide the MeRLin [YW(EB1] [ME2] provider client free of charge for this purpose. Alternatively, it is also possible to connect an in-house development via the provider interface.

The figure below shows the communication interfaces between MOLS and the providers. Data exchanges that are not directly relevant for activation are shown in gray. Communication to MARI is also shown in gray. If the platform is not available, mFRR calls are handled locally. Confirmation files (ACK) are not included in the figure to improve clarity.

The MOLS receives both master data and the allocation result from the internet platform www.regelleistung.net. Similarly, all mFRR providers directly receive the information from this platform about whether offers were awarded or rejected.

On the call day itself, the MOLS exchanges various files with the provider's call system, such as communication tests to verify communication between MOLS and the provider, activation and deactivation messages, as well as their confirmations.

The MOLS, along with all other connected foreign TSOs, sends all demands and bids to MARI. These are then optimized by MARI. Subsequently, MARI transmits the capacities to be activated to the MOLS.

 At the end of the day, the MOLS sends trading confirmations to the providers' call systems to exchange the latest status of activations and available capacity with the mFRR provider for consolidation. 

Call of capacity 

The call of mFRR is generally carried out in ascending order of work prices (merit order) for positive activation direction, and in descending order for negative activation direction. In case of same price, the decision is made randomly. It is not permissible to curtail an offer designated as indivisible during call-off. By connecting to MARI, the order is extended to foreign bids.

There is a distinction between Scheduled Activation (SA) and Direct Activation (DA). An SA refers to a specific quarter-hour (MTU0). This type of activation is preferred by the German TSOs. A DA, on the other hand, allows for mFRR to be activated at any given time. The activation period ends with the end of the next quarter-hour (MTU1). The figures below illustrate the differences and the temporal sequences.

In the case of a call, the providers receive an activation message no later than 7.5 minutes before the start of the activation period. The full activation time is 12.5 minutes after the activation time, including the preparation phase and ramp period.

The delivery should be as linear as possible. A ten-minute activation and a ten-minute deactivation period are provided. 50% of the requested balancing capacity must be delivered at the beginning of the activation period. The full called power must be reached no later than 5 minutes after the start of the activation period and must be maintained until at least 5 minutes before the end of the activation period. At the end of the activation period, at least 50% of the called power must still be delivered.

The offered balancing capacity must be provided effectively within the transmission gird area of the connecting TSO.