Iberian blackout on 28 April 2025 – Publication of the ENTSO-E investigation report

24 March 2026

On Monday, 28 April 2025, a significant incident occurred on the Iberian Peninsula, leading to a total blackout in Spain and Portugal and short duration disturbances in a small area of Southwest France. According to the Incident Classification Scale (ICS) Methodology, the incident is classified as a scale 3 blackout.

In line with the ICS Methodology (developed in accordance with Regulation (EU) 2019/943), the scale 3 classification meets the RCC investigation threshold. Consequently, an RCC investigation subgroup was established under the Regional Coordination Centre Post Operation and Post Disturbances Analysis and Reporting (RIAR) Methodology, in accordance with Article 37(1)(i) of Regulation (EU) 2019/943.

The conclusions of this RCC investigation are incorporated into the Final Report that has now been published. This report describes the sequence of events and identifies the technical drivers behind the blackout, including voltage and reactive power control challenges, oscillations, and cascading generator disconnections. The report also provides recommendations to strengthen operational practices and cross border coordination to prevent similar incidents.

The final report can be found here: 28 April 2025 Blackout – ENTSO-E dedicated page.