CNMC Rules Against Retroactive Application of New Dynamic Stability Criteria in Grid Access Denial for Almoguera Hybrid Solar-Storage Project
DecisionCNMC's Sala de Supervisión Regulatoria resolved access conflict CFT/DE/120/26 in favor of LIBIENERGY ENERGÍAS, S.L., annulling REE's 1 April 2026 denial of a grid access/connection permit update for hybridizing the 'Almoguera 1' photovoltaic plant with a 43.8 MW BESS at the José Cabrera 220 kV node. CNMC determined that LIBIENERGY's request (filed 29 January 2026, completed 12 February 2026) predated the 20 February 2026 publication of the first demand capacity map, and therefore must be evaluated under the pre-Especificaciones de Detalle technical criteria per the transitional provision (disposición transitoria segunda) of Circular 1/2024, not the new 'dynamic zonal behaviour' criterion that REE applied retroactively.
The ruling establishes a binding precedent on the temporal scope of new grid-access capacity methodologies in Spain, clarifying that TSOs cannot apply newly effective technical criteria (such as dynamic stability/zonal behaviour thresholds) to requests admitted before the formal trigger date for those criteria (publication of the first capacity map). This directly affects how storage hybridization and other demand-side connection requests are evaluated during methodology transitions, with implications for investment certainty in battery storage and renewable hybridization projects navigating evolving grid-access rules.
This is a methodology-transition dispute rather than a market-design proposal, but it has real market-design consequences: it narrows TSO discretion to invoke newer, more restrictive capacity criteria against requests filed under a prior regime, reinforcing the primacy of transitional provisions in Spanish grid-access regulation (RD 1183/2020, Circular 1/2024, Especificaciones de Detalle). For storage and hybrid project developers, the decision reduces regulatory risk from 'criteria creep' during capacity-map rollouts, and signals that CNMC will scrutinize TSO denials for compliance with motivation requirements under Article 33 Ley 24/2013. It also foreshadows further contention once the dynamic criteria (Annex 1 §4.3) become generally applicable following the October 2026 capacity maps, which may generate similar conflicts for requests filed after that effective date.
Ley 24/2013 del Sector Eléctrico (Art. 33); Ley 3/2013 de creación de la CNMC (Art. 12.1.b, 14, 21.2.b); RD 657/2013 Estatuto Orgánico CNMC; RD 1183/2020 de acceso y conexión (Art. 9, 20 quater); Circular 1/2024 CNMC (Art. 8, disposición transitoria segunda); Especificaciones de Detalle para capacidad de acceso de demanda (Resolución CNMC 1 diciembre 2025, Resuelve Octavo); Ley 39/2015 LPAC (Arts. 21.4, 73.1, 82)
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