The unexpected power outage that halted the Iberian peninsula at the end of April was caused by an overload of electricity that triggered a chain reaction of disconnections within the power grid, according to an expert report commissioned by the Spanish government. The Spanish environment minister, Sara Aagesen, ruled out a cyber-attack as the cause of the 28 April outage, attributing it instead to a “multifactorial” system failure resulting from the grid’s inability to manage voltage levels. She explained that the Spanish national grid operator, Red Eléctrica, lacked sufficient thermal power stations to control the surge, and that certain power-generating companies had failed to absorb voltage fluctuations as they were supposed to.
The blackout led to widespread disruptions in Spain and Portugal, including the loss of trains, metros, traffic lights, ATMs, phone connections, and internet access. The power failure prompted the government to commission the expert report. Aagesen stated that the outage was the result of “surging tensions” and a chain reaction of control disconnections which caused further power losses. Investigations focused on an incident at 12:33 PM on April 28, when 60% of the energy being used suddenly went offline for five seconds.
The minister highlighted that there had been signs of “voltage instability” in the days leading up to the outage and oscillations in the system between noon and 12:30 PM on the day it occurred. She explained that the failure progressed in three phases: power losses, and then a peninsular collapse. The report’s key recommendations include strengthening supervision and ensuring Spain’s ability to withstand future voltage fluctuations. Aagesen defended the government’s commitment to renewable energy, denying any link between the energy transition and the blackout, which some had suggested as a cause.
She and Prime Minister Pedro Sánchez have repeatedly dismissed any accusation that the blackout was linked to the phasing out of nuclear energy in favor of renewables. Aagesen stated that Spain’s energy mix on the day of the outage was identical to past scenarios where the system had worked without incident, indicating that blaming renewables for the failure was not appropriate. Both Aagesen and Sánchez denied claims that the failure was due to a government experiment in renewable energy production.
The publication of the report coincides with ongoing political challenges facing Spain’s Prime Minister, Pedro Sánchez, who is grappling with corruption allegations within his own party. Despite pressures for a snap election, Sánchez has rejected the idea, emphasizing his commitment to fighting corruption and the continuity of his government’s projects for the country. He contrasts his approach to dealing with corruption with that of the conservative People’s party, which he succeeded after it was engulfed in a significant graft scandal.
Source: https://www.theguardian.com/world/2025/jun/17/expert-report-rules-out-cyber-attack-for-spain-and-portugal-april-blackout
