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 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.

The 2021 Biennial Progress Report on Operational Probabilistic Coordinated Security Assessment and Risk Management (2021 Biennial PRA Report) provides a view on TSOs’ progress towards PRA, outlining the expected challenges and the next steps towards the probabilistic risk assessment methodology to be developed by 2027.

The PRA progress report is available here.