In Europe, power system operational security management has relied on the ‘N-1’ criterion as the principle governing contingency analysis. “N-1” contingency analysis means that the power system is always able to withstand an unexpected failure or outage of a system component while accommodating the new operational situation and without violating the existing security limits.

The Probabilistic Risk Assessment (PRA) is a complementary approach to the ‘N-1 criterion’ for contingency analysis. It allows TSOs to assess the probability, and subsequently the impact, of the failure of the power system, in establishing the operational security limits.

In accordance with article 44 of the Methodology for coordinating operational security analysis (CSAM), all TSOs shall jointly develop the PRA methodology.

In December 2021, ENTSO-E published the first Biennial Progress Report on Operational Probabilistic Coordinated Security Assessment and Risk Management (Biennial PRA Report).

This new report describes the accomplishments in this framework since 2022.

The 2023 Biennial PRA Report is available here.