The final report of the Expert Panel on the 28 April 2025 blackout in continental Spain and Portugal identifies its causes and outlines recommendations to strengthen the resilience of Europe’s interconnected electricity system. It was prepared by a 49-member Panel including representatives from Transmission System Operators (TSOs), Regional Coordination Centres (RCCs), ACER and National Regulatory Authorities (NRAs), and was chaired by experts from two unaffected TSOs.  

The investigation concludes that the blackout resulted from a combination of many interacting factors, including oscillations, gaps in voltage and reactive power control, differences in voltage regulation practices, rapid output reductions and generator disconnections in Spain, and uneven stabilisation capabilities. These factors led to fast voltage increases and cascading generation disconnections, resulting in the blackout in continental Spain and Portugal.  

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 strengthened operational practices, improved monitoring of system behaviour and closer coordination and data exchange among power system actors. The findings of the investigation also underscore the need for regulatory frameworks to adapt in order to support the evolving nature of the power system.  

The 28 April 2025 blackout was a first of its kind event, and the recommendations aim to strengthen system resilience with solutions that are already technologically deployable. This blackout highlights how developments at the local level can have system-wide implications and underlines the importance of maintaining strong links between local and European system behaviour and coordination, while ensuring that market mechanisms, regulatory frameworks and energy policies remain aligned with the physical limits of the system. 

Read the full report here.