Secondary control reserve
The secondary control reserve covers small system imbalances. Providers of secondary control reserve offer services automatically as requested. Secondary control reserve activates to decrease the use of primary control reserve.
Historical development of secondary control reserve
Since December 1, 2007, the German TSOs have been procuring their secondary control reserve demands via a joint tender on the internet platform regelleistung.net. This platform provides tenders, the submission of bids, and informs bidders of allocations and rejections.
On 18/10/2011, the market design that applied until then was revised for the first time and updated again on 13/06/2017. The new market design was introduced in two stages as of 12/07/2018 and 12/07/2019.
As of 02.11.2020 (delivery date 03.11.2020) the balancing energy market was introduced with separate procurement of balancing capacity at the balancing capacity market and balancing energy at the balancing energy market.
The introduction of the balancing energy market is the national basis for the European domestic market for control reserve and corresponds with the requirement in article 16 (5) EB-VO. At the end of the tendering of balancing capacity the BSPs have the possibility to adjust the accepted bids and/or can offer new bids.
The design of the balancing energy market is outlined in § 38 of the modalities for BSPs (MfRRA).
Overview of current business rules:
| Capacity market | Gate Opening: d-7, GCT: 9 o'clock, product length 4 hours |
| Energy Market | Gate Opening: d-1 (ca. 12 o'clock), GCT: t-25, product length 15 minutes |
| Core Share | Countries provide the core share and cross border capacities, no core share within Germany |
| Minimum offer capacity | 1 MW |
| Pooling | possible inside control area |
| Indivisible offer | indivisible offer not possible |
| Activation | Automatic activation through TSO |
| Activation Period | full activation within 5 minutes |
| Backup | backup possible |
Additional information
The prerequisite for participation in the joint tender is the conclusion of a framework agreement between the supplier and the connecting TSO following successful prequalification. The prequalified reserve must be at least 1MW.
The connection TSO is the TSO in whose control area the technical units to be marketed by the supplier are connected to the grid, irrespective of the voltage level. This TSO carries out the prequalification of technical units (e.g. generation units or controllable consumer loads) in its control area and is the contractual partner of the supplier whose technical units are located in the control area of the connecting TSO. If a supplier markets technical units in several control areas, a framework agreement must be concluded with the relevant connecting TSO in each case.
Each bidder has access to an individual secure bidder area on the Internet platform for the submission of bids and collection of results. The invitation to tender takes place every calendar day.
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 2020, 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.