On June 25, with the delivery day on June 26, local technical difficulties on the side of EPEX SPOT led to the partial decoupling of the Single Day-Ahead Market Coupling (‘SDAC’). Despite these technical difficulties, the day-ahead electricity market in the Czech Republic, organized by OTE, remained coupled with other markets in the Core and EU regions, except for Denmark, Estonia, Finland, Latvia, Lithuania, Norway, and Sweden. As a result, the order books (‘OBKs’) of EPEX SPOT (for the CORE, Nordic, and Baltic regions) and EMCO – Nordpool (for the Nordic and Baltic regions only) were not included in the SDAC coupling process.

The incident was caused by technical difficulties on the side of EPEX SPOT, which prevented the submission of the order book by EPEX SPOT before the deadline set in the binding procedure, resulting in the partial decoupling of the single day-ahead market coupling. This partial decoupling was declared in accordance with the relevant operational procedures at 13:05 CEST. In the CORE region, cross-border capacities were successfully allocated fully in accordance with the regional procedure, without any limitations within the implicit trading among the remaining nominated electricity market operators. Therefore, it was not necessary to activate backup mechanisms for so-called “shadow” auctions in the CORE region.

The Nordic and Baltic capacity calculation regions were decoupled in accordance with regional backup procedures, which prioritized market coupling within the respective regions over the single market coupling. Despite these challenging events, the SDAC coupling process was completed at 14:09 with the publication of the results in the coupled markets, including the Czech market.

On the following day, June 26, with the delivery day on June 27, the single day-ahead market was run successfully in fully coupled mode with the involvement of all bidding zones and order books.

On the same day, June 25, 2024, earlier in the day, the same technical issue on the side of EPEX SPOT also led to the cancellation of the 3rd Intraday Auction (‘IDA3’) at 10:00 CEST for the delivery day on June 25 and subsequently to the organization of the first Intraday Auction for the delivery day on June 26 (‘IDA1’ at 15:00 CEST) without the Nordic and Baltic capacity calculation regions and without the EPEX SPOT order book. Based on the information regarding the resolution of the technical issue by EPEX SPOT, the second Intraday Auction for the delivery day on June 26 (‘IDA2’ at 22:00 CEST) was successfully performed in fully coupled mode.

The Market Coupling Steering Committee (‘MCSC’) initiated a detailed investigation, with conclusions expected to be published within a month in the final incident report. However, it can already be emphasized that the central systems and the common algorithm were fully operational throughout the incident, and the cause was local issues of one of the nominated electricity market operators within the coupled single day-ahead and intraday electricity market.

Further details on these incidents are provided in the official report of the MCSC, available here.