ENTSO-E Blames Voltage Cascades for Massive Iberian Blackout
ENTSO-E has published a report on the widespread power outage that struck Spain and Portugal on April 28, 2025, affecting around 60 million people. The blackout, which started at 12:33 PM and lasted for several hours, resulted in at least seven deaths, including three from carbon monoxide poisoning due to backup generators. A detailed investigation, involving over 75 experts and analyzing more than 300 gigabytes of data, has identified voltage cascades as a central factor in the collapse of the entire system.
The Iberian power grid's structural peculiarities influenced the likelihood and resolution of the problem. Initial findings showed that three consecutive power outages in substations triggered the blackout within 20 seconds. Despite the high share of renewable energies in Spain, they did not contribute to the outage. The restoration process took several hours, with some isolated networks not reconnected until the next morning. Experts now consider batteries crucial for future network stability. In response, ENTSO-E is expected to publish specific recommendations in the first quarter of 2026 to improve European grid stability and learn from this incident. These may include enhancing transmission capacities, increasing redispatch capabilities, supporting renewable energies, strengthening risk management, fostering cooperation, bolstering cybersecurity, and promoting resilience and flexibility.
The Iberian blackout of 2025 has highlighted the need for improved network management and cooperation across Europe. ENTSO-E's upcoming recommendations aim to enhance grid stability, resilience, and flexibility, ensuring that lessons learned from regional events like this are applied across the continent.
