NEMO Committee publishes Version 1.4 of the SDAC Fallback Manual, updating decoupling and fallback procedures

The NEMO Committee released an updated Version 1.4 of the Single Day-Ahead Coupling (SDAC) Fallback Manual on 30 September 2026, described as containing 'highlighted changes versus previous version'. The manual sets out the operational timeline for normal SDAC days, delay situations without decoupling, and detailed procedures for Partial Decoupling (due to cross-zonal capacity issues, during the coupling process, or known in advance) and Full Decoupling, together with the associated market messages (SDAC_ExC/UMM series), fallback allocation mechanisms per interconnector, and regional annexes for Core, IBWT, Nordic-Baltic, Poland, RO-BG and South-Western Europe.

The Fallback Manual is the operational rulebook that determines how price formation and cross-zonal capacity allocation continue when the SDAC day-ahead coupling algorithm or NEMO/TSO processes fail, partially or fully. Any update to decoupling deadlines, fallback allocation logic (Shadow Auctions vs Intraday vs 'back to owner') or regional annex procedures directly affects market continuity, price formation integrity and cross-border capacity usage for all SDAC bidding zones on delay/decoupling days.

This is a NEMO Committee operational document rather than a regulatory consultation or legislative proposal, so it sits at the IMPLEMENTATION stage of the market-design lifecycle: it codifies already-operative fallback procedures (with detailed, minute-level timelines such as the 10:30 known-in-advance deadline, 11:30 CZC-related partial decoupling deadline, 13:00 partial decoupling deadline, and 14:20 full decoupling deadline) rather than proposing new rules for consultation. The significance for market design lies in the granularity of the fallback allocation matrix per interconnector (Shadow Auctions via JAO, Intraday market, 'back to owner', or regional coupling continuation for Nordic-Baltic and Iberia), which effectively defines de facto cross-zonal capacity allocation rules in stress scenarios. Because the source text flags 'highlighted changes versus previous version' without specifying which particular timelines, thresholds or allocation rules were altered relative to Version 1.3, the precise scope of the design change cannot be confirmed from this source alone and should be treated as an implementation-detail update to an existing framework rather than a structural redesign.

CACM Regulation (Capacity Allocation and Congestion Management) - referenced as governing capacity provision deadlines; SDAC operational procedures as established under NEMO Committee/ENTSO-E governance

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Primary sources