ENTSO-EToday, the Expert Panel set up by ENTSO-E to investigate the 18 May 2025 blackout in North Macedonia has published its comprehensive factual report.
On 18 May 2025, at 04:59 CEST, the power system of North Macedonia experienced a separation between the 400 kV and 110 kV transmission networks due to overvoltage. This event led to a full blackout in the 110 kV network, which resulted in the loss of approximately 79% of the total load in the country.
MEPSO, the Transmission System Operator (TSO) of North Macedonia, immediately initiated the system restoration process, which was completed at 07:47 CEST, less than 3 hours after the blackout.
On the same day, the Bulgarian control area entered an alert state for 8 hours due to high voltages in the western part of the system. The remainder of the Continental Europe (CE) power system did not experience any significant disturbance.
The factual reportpresents a detailed account of the system conditions on 18 May leading up to the blackout, the sequence of events, and the restoration process. ENTSO-E established an Expert Panel to perform an investigation of the event under Commission Regulation (EU) 2017/1485 of 2 August 2017 establishing a guideline on electricity transmission system operation (SO GL), and the Incident Classification Scale (ICS) Methodology. In alignment with the respective legal requirements, the Expert Panel consists of representatives from TSOs, the Agency for the Cooperation of Energy Regulators (ACER), National Regulatory Authorities (NRAs), and Regional Coordination Centres (RCCs). The investigation also relies upon extensive data collection from neighbouring transmission system operators.
The factual report serves as the first major report of the Expert Panel and has been prepared in line with the applicable regulations. The last step of the investigation will involve the final report, expected in Q1 2026, which will include a detailed root cause analysis and recommendations to help prevent similar incidents in the future.
Press contact
About ENTSO-E
ENTSO-E, the European Network of Transmission System Operators for Electricity, is the association for the cooperation of the European transmission system operators (TSOs).
The 40 member TSOs, representing 36 countries, are responsible for the secure and coordinated operation of Europe’s electricity system, the largest interconnected electrical grid in the world. In addition to its core, historical role in technical cooperation, ENTSO-E is also the common voice of TSOs.
Press contact: media@entsoe.eu