Methodologies for Assessing the Needed Flexibility

S. Ruggeri, S. Cianotti, C.Y. Evrenosoglu, I.M. Gianinoni, A. Meletiou, M. Troncia

Summary:

This paper presents a structured review of methodologies for assessing the flexibility needs of modern power systems, with a focus on both transmission and distribution levels. Flexibility is analyzed as a system-wide requirement to accommodate the variability and uncertainty introduced by renewable generation, and as a resource-side or grid-side capability enabled by controllable assets. The study introduces conceptual definitions and categories of flexibility, including needed, potential, and feasible flexibility, and explores diverse modeling paradigms ranging from heuristic rules to optimization, data-driven, and physics-based approaches. The paper also discusses recent regulatory frameworks such as the European Flexibility Needs Assessment (FNA) and identifies key criteria for evaluating flexibility requirements across spatial and temporal dimensions. Finally, the report offers a synthesis of emerging practices and highlights the operational, economic, and policy implications of flexibility deployment, supporting informed decision-making in energy system planning and management.

Spanish layman's summary:

El informe revisa metodologías para evaluar necesidades de flexibilidad en transporte y distribución: enfoques basados en reglas, optimización, datos y métodos probabilísticos, junto con regulación y casos de proyectos europeos.

English layman's summary:

The report reviews methodologies for assessing flexibility needs at transmission and distribution levels, covering rule-based, optimisation, data-driven and probabilistic approaches, regulatory developments and European project case studies.

Keywords: Flexibility needs assessment, power system flexibility, DSO, TSO, local flexibility markets, grid planning, optimisation, probabilistic methods, distributed energy resources

IIT Project: BeFlexible (BeFlexible)

Funding entity: Comisión Europea. Horizon Europe

Publication date: 14-Sep-2026