- After a sudden blackout affected millions, Spain and Portugal restored power to 99% of the region.
- Experts suspect renewable generation imbalances but ruled out cyberattacks, human error, or weather.
- Analysts urge stronger EU grid connections, storage, and stabilising systems to support renewables.
Spain and Portugal restored power to 99 per cent of the Iberian Peninsula after a major blackout on Monday, April 28. The outage left millions without electricity, and officials continue investigating the cause.
Spain’s grid operator, Red Eléctrica, linked the incident to two sudden “generation disconnections.” The company suspects fluctuations in renewable energy are a possible trigger. It ruled out cyberattacks, human error, or extreme weather.
Experts say these rare blackouts are part of the grid’s built-in protection system. When power supply and demand drift apart, the grid disconnects sections to prevent damage.
“This blackout happened in just five seconds,” said Álvaro de la Puente Gil, an electrical engineering professor at the University of León. “More than half of Spain’s generation capacity dropped, and the system shut down to protect itself.”
Grid operators constantly monitor frequency, voltage, and load to maintain balance. When significant imbalances occur, automatic safety systems cut off network parts. In severe cases, the entire grid can go offline.
Spain’s grid includes strong internal connections but suffers from weak links to Europe. “Our high-voltage mesh works well,” said Miguel de Simón Martín, another professor from the University of León. “But we lack strong interconnections with France and other countries.”
Spain only connects 3 per cent of its electricity capacity to the European grid, far below the EU’s 15 per cent target for 2030. This limited link reduces Spain’s ability to import or export power during emergencies.
Spain’s push for renewables may have added stress to the system. At the end of 2024, renewables comprised 66% of installed capacity and delivered nearly 59% of the country’s electricity. Wind, solar, and hydro served as the primary sources.
Unlike thermal or hydroelectric plants, wind and solar systems don’t use large spinning turbines. These turbines provide mechanical inertia, which helps the grid resist sudden shifts in energy flow. Solar and wind systems rely on electronic inverters, which don’t offer this buffer.
“Synchronous generators act like shock absorbers,” De Simón Martín explained. “Without them, the grid reacts more sharply to disruptions.”
He warned that Spain’s grid has become more vulnerable due to its weak interconnections and high share of inverter-based renewables.
Experts recommend several measures to prevent another failure. They urge operators to limit solar generation during low demand and prioritise power sources that supply inertia. They also call for more energy storage systems and grid stabilisers.
“We need stronger connections with France,” said De la Puente Gil. “We must invest in flexibility and storage to support renewable growth.”
Spanish Prime Minister Pedro Sánchez addressed the outage in a press briefing on Tuesday, April 29. He denied that renewable energy or poor interconnection caused the blackout but said officials would not rule out any possibility.
The Spanish government and European Commission launched formal investigations. Experts stress that Spain must act quickly to improve grid resilience and secure its energy future.