ENTSO-E has released the expert panel’s final report on the Iberian blackout incident on 28 April 2025. According to the report, the blackout resulted from a rapid, uncontrolled voltage surge and cascading disconnections of generation units, primarily in Spain.
The incident was triggered by a combination of oscillatory instability (0.63 Hz local and 0.2 Hz inter-area oscillations), inadequate voltage control, and insufficient reactive power management. The blackout cascaded within seconds, isolating the Iberian Peninsula from the Continental European grid. Restoration took 12–16 hours, but revealed gaps in real-time monitoring, cross-border coordination, and DSO-TSO communication.
ENTSO-E recommendations focus on:
- Strengthening automated voltage control and dynamic reactive power support.
- Enhancing oscillation damping (e.g., mandatory PSS, improved HVDC POD functionality).
- Aligning protection settings with system-wide voltage limits.
- Improving data sharing and operational planning between TSOs, DSOs, and generators.
This report was prepared by a panel of international members, including GO15 members RTE, Swissgrid and Terna.