The Expert Panel established to investigate the blackout that occurred on 18 May 2025 in North Macedonia releases its final report. The report identifies the causes of the blackout and outlines recommendations to strengthen the resilience of Europe’s interconnected electricity system. It was prepared by an 18-member Panel including representatives from Transmission System Operators (TSOs), ACER and National Regulatory Authorities (NRAs). The Panel was chaired by an expert from 50Hertz, as an unaffected TSO.
The investigation concludes that the blackout resulted from operating the transmission system in North Macedonia above the defined voltage limits of 420 kV. This overvoltage situation led to the tripping of all 400/110 kV transformers, resulting in the 400 kV network being separated from the 110 kV network and causing the blackout in Northern Macedonia.
Based on these findings, the Expert Panel sets out recommendations addressing each of the factors identified in the report to help prevent similar events in the future. These include an action plan for the entire South-East Europe (SEE) region to mitigate high-voltage conditions, as well as a recommendation for stronger alignment among TSOs on operational voltage control measures, supported by RCCs and ENTSO-E.
This blackout highlights the importance of enhancing voltage control measures and cooperation among TSOs, DSOs, Significant Grid Users, and National Regulatory Authorities to improve system resilience across the SEE region.
Read the full report here.