Critical analysis of the new European framework for non-fossil flexibility and the questions left unanswered

P. Mastropietro, P. Rodilla, J.P. Chaves

iScience Vol. 29, nº. 11, pp. 117859

Summary:

The 2024 Electricity Market Design Reform introduced a new European framework for non-fossil flexibility. The first national flexibility needs assessments were published in July 2026, and indicative objectives and support schemes for non-fossil flexibility will soon be introduced. However, we argue that this new framework, which will influence the development of European power systems as they transition to low-carbon resources, is based on a flawed theoretical foundation and exhibits significant overlap with the European resource adequacy framework. No flexibility metric has been defined for the flexibility needs assessment. No flexibility standard/target has been calculated based on the economic equilibrium between the cost of additional flexibility and the cost of not relying on it. We identify three underlying metrics for flexibility needs, we present alternative approaches to define flexibility products and identify open questions that need to be addressed before the new flexibility framework moves to the implementation phase.

Spanish layman's summary:

El artículo ofrece una evaluación crítica del nuevo marco europeo sobre la flexibilidad no fósil. En él se identifican tres métricas para evaluar las necesidades de flexibilidad, se presentan enfoques alternativos para definir los productos de flexibilidad y se señalan cuestiones pendientes.

English layman's summary:

The article presents a critical assessment of the new European framework for non-fossil flexibility. It identifies three underlying metrics for flexibility needs, it presents alternative approaches to define flexibility products and identifies open questions.

Keywords: flexibility needs assessment; non-fossil flexibility; flexibility support schemes; resource adequacy; reliability standards; capacity mechanisms; RES integration; RES target; flexibility services

JCR-JIF Impact Factor and WoS quartile: 4,500 - Q1 (2025)

DOI reference: https://doi.org/10.1016/j.isci.2026.117859

Published on paper: November 2026.

Published on-line: October 2026.

Citation:
P. Mastropietro, P. Rodilla, J.P. Chaves, "Critical analysis of the new European framework for non-fossil flexibility and the questions left unanswered", iScience, Vol. 29, nº. 11, pp. 117859, November 2026. [Online: October 2026] doi: 10.1016/j.isci.2026.117859