EPEX SPOT Exchange Council Calls for Practical Fallback Solutions for SDAC Decoupling and Highlights Core Region Timeframe Constraints

At its 16 September 2026 quarterly meeting, the EPEX SPOT Exchange Council discussed options to amend full decoupling fallback solutions for the Single Day-Ahead Coupling (SDAC), stressing that arrangements should be simple, predictable and proportionate. The Council flagged the comparatively tight Day-Ahead timeframe in the Core region (Central Western Europe) as a recurring concern versus longer timelines in other coupled regions, and called for robust, scalable pan-European Intraday trading infrastructure. EPEX SPOT also introduced the TBx (Top-Bottom) Index Suite for battery storage valuation, welcomed by Council members, and marked the 20th anniversary of Market Coupling in the EU.

SDAC fallback design directly affects how European Day-Ahead markets behave during decoupling incidents, influencing price formation, cross-border volume allocation and market transparency in exceptional circumstances. The Core region's tighter incident-resolution timeframe versus other coupled regions is a structural asymmetry that could increase decoupling risk. Infrastructure reliability concerns for Intraday trading and new storage valuation benchmarks (TBx) also signal evolving market design priorities as flexibility assets scale.

This is an early-stage institutional discussion at EPEX SPOT's official governance body (Exchange Council), occurring against the backdrop of parallel ACER-TSO-NEMO discussions on SDAC fallback arrangements. No concrete rule change or formal proposal has been adopted yet; the Council is signaling design principles (simplicity, proportionality, predictability) and identifying a structural problem (Core region's tight Day-Ahead timeframe) rather than finalizing solutions. This sits upstream of any CACM-driven regulatory process and should be tracked as it likely feeds into a future ACER/TSO/NEMO proposal on SDAC fallback methodology. The TBx Index Suite launch and Market Coupling anniversary are contextual/adjacent market design developments bundled into the same announcement but represent separate, already-implemented initiatives rather than open design questions.

EU CACM Regulation (Market Coupling and fallback procedures framework)

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