Today, the Expert Panel set up by ENTSO-E to investigate the grid incident of 4 July 2025 in the Czech Republic has published its comprehensive factual report.

On 4 July 2025, shortly before 12:00 CEST, an incident occurred in the Czech power system which led to significant outages, affecting grid elements and power units, in the eastern and northern part of the Czech Republic including the Prague area. Part of the transmission network went into island operation, disconnecting from the larger national system, and almost immediately collapsed.

The Czech transmission system operator (ČEPS) immediately activated its system restoration plan. By 14:09 CEST, all the affected transmission system substations were put back into operation. By 17:35 CEST, the supply of all the load lost in the incident was also restored.

The factual report, now available on the ENTSO-E website, presents a detailed account of the system conditions on 4 July leading up to the loss of the islanded area, the sequence of events, and the restoration process. ENTSO-E established an Expert Panel to investigate the incident, in accordance with 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 line with the legal requirements, the Expert Panel consists of representatives from transmission system operators (TSOs), the Agency for the Cooperation of Energy Regulators (ACER), National Regulatory Authorities (NRAs), and Regional Coordination Centres (RCCs).

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 Q2 2026, which will include a detailed root cause analysis of the incident and recommendations to help prevent similar events in the future.

• Read the report