Common tendering secondary control reserve

Since 1st December 2007, the German transmission system operators (TSOs) cover their need for secondary control reserve via a common tendering procedure in accordance with the requirements stipulated in the Energy Industry Act (abbreviated as "EnWG" in German) of 7th July 2005 and the associated Electricity Network Access Ordinance ("StromNZV").

With the introduction of the common tendering of secondary control reserve, the Reserve Connecting TSO assumes a primary role. The Reserve Connecting TSO is that German TSO, in the control area of which the technical units to be marketed by the supplier, are connected to the grid and to the control system (independently of the voltage level).

The Reserve Connecting TSO conducts the prequalification procedure of technical units (generation facilities and controllable consumer loads) which are connected to the grid in its control area, regardless of the voltage level. In addition, it is the sole contractual partner of the bidder. The technical units are used for provision of SCR in the control circuit of the load-frequency controller at the Reserve Connecting TSO. If a bidder markets technical units in several control areas, a framework agreement with all the relevant Reserve Connecting TSOs has to be concluded.

After a successful prequalification, the framework agreement with the Reserve Connecting TSO is concluded, as far as the prequalified minute reserve is equal to the minimum lot size. The FNA fixed the minimum lot size at 5 MW. By way of derogation, a lot size of 1 MW, 2 MW, 3 MW or 4 MW is admissible, provided that a BSP of SCR submits only one offer per product time slice of the positive or negative SCR in the respective control area. The framework agreement is a prerequisite for the participation in the common tendering of secondary control reserve.

Because of the grid control cooperation in Germany, a supplier automatically takes part in the entire German secondary control reserve market.

The common internet platform regelleistung.net is used for the processing of the tender. Via this internet platform, the publication of tenders, the completion of tender submissions and the BSP information on acceptance of offers and/or refusals are announced.

With the publication of each new tender, the TSOs announce the total requirement as well as the needs of all four German control areas as required by Section 6 (2) of the Electricity Network Access Ordinance (StromNZV).

The tender and assignment for SCR is given for each calendar day. For this purpose, a tendering calendar is available for download on the Internet platform.

Other key issues are regulated by the FNA's decisions BK6-15-158 and BK6-18-019.

For the lodging of tenders and collection of the results (including the assignment of successful offers to the different TSOs) all BSPs have an individually secured BSP's domain at their disposal.

The tendered quantity, the anonymised offer list and the activated secondary control reserve are published in the freely accessible area of this internet platform in accordance with the decision by the FNA mentioned earlier.

SCR Cooperation with Austria - aFRR ATDE

The German and Austrian transmission system operators (TSOs) are already part of the International Grid Control Cooperation(IGCC). In this co-operation, the Counter activiation of secondary control power (SCR, aFRR) is avoided by implementing an imbalance netting in both countries.

As a next step, the German and Austrian TSOs have now deepened their cooperation by optimizing SCR activation on the basis of a common merit list and based on a TSO TSO model since July 2016. Provided there are no operational network restrictions at the common border this lowers the costs of activation.

Since the beginning of 2019, a joint procurement of SRL is carried out. All offers from Austria and Germany are brought together and awarded jointly. Country-specific core shares and the available crossborder capacities are taken into account. The amount of available cross-zonal capacities (CZC) will be determined in a weekly cost-benefit analysis and reserved accordingly. The details of the call for tenders can be found in the EBGL application document and the details of the cost benefit analysis can be found here.