How Spain’s Massive Blackout Led to an Investigation with Greek Expert Involvement

The large-scale blackout in Spain that occurred two weeks ago highlighted the importance of a resilient energy grid, especially in an era where electricity dependence is higher than ever. As it was one of the largest blackouts in Europe in decades, many noted differences compared to past outages. For example, older landline phones used to function during power cuts, but this is no longer as reliable due to reliance on fiber-optic networks. Consequently, there is an evident need to strengthen the grid as electrification accelerates across sectors like transportation and industry. Authorities are now tasked with answering questions about what caused the outage in Iberia. So far, we’ve only had the initial sequence of events published by Spain’s operator Red Electrica. Now, the European Network of Transmission System Operators for Electricity (ENTSO-E) has released a more detailed timeline offering a fuller picture. However, definitive answers may take months, according to market experts. Currently, ENTSO-E has launched its investigation, led by a team of specialists from various countries, including Greece. Specifically, Maria-Phaedra Katsiantoni is one of ten members of this team and belongs to the staff of the SEleNe CC coordination center established in Thessaloniki in 2020. This center involves operators from Greece, Bulgaria, and Italy—ADMIE, ESO, and Terna. It’s worth noting that SEleNe CC also participated in the investigation of the Balkan blackout in June 2024, affecting Albania, Bosnia-Herzegovina, Montenegro, and Croatia. According to ENTSO-E, half an hour before the blackout, two fluctuations in power and frequency were observed in the European electricity network between 12:03–12:07 and 12:19–12:21. Managers in Spain and France acted to stabilize the situation, and when the main incident occurred, all variables were stable in the system. Just before the blackout, Spain was exporting 1,000 MW to France, 2,000 MW to Portugal, and 800 MW to Morocco. During the blackout itself, starting at 12:32:57, a series of disconnections occurred in southern Spain over 20 seconds, leading to a loss of 2,200 MW. Frequency dropped and power surged in Spain and Portugal. Between 12:33:18 and 12:33:21, frequency continued to fall, reaching 48.0 Hz on the Iberian Peninsula, triggering automatic load-sharing defenses in Spain and Portugal. At 12:33:21, AC lines between France and Spain disconnected due to protective devices. By 12:33:24, the Iberian system collapsed entirely, halting HVDC line energy transfer between France and Spain. Post-blackout, managers collaborated to restore power through several key steps, including reactivating the 400 kV France-Spain line at 12:44, reconnecting Spain-Morocco links at 13:04, and fully restoring both Portuguese and Spanish transmission networks by early morning on April 29.