Spanish government reports on cause of Iberian blackout

• 2 days ago (2025-06-20)
• David Flin

Distribution 140 Europe 1123

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The Spanish Government has issued a report on its findings into the cause of the blackout that affected Spain and Portugal on 28 April 2025. The report states that the primary cause of the blackout was the failure of Spanish grid operator REE to calculate an adequate energy mix and maintain voltage levels.

The report also identifies the failure of old power plants to maintain appropriate voltage control on the day of the blackout.

Sara Aagesen, Spain’s Energy Minister, said: “The system did not have sufficient voltage control capabilities, either because they were not sufficiently programmed, or because those that were programmed did not adequately provide what was required by the standard, or a combination of both. REE told us that they made they made their calculations and estimated that switching on more thermal plants was not necessary at this time. They only set it for the early hours of the day, not the central hours.”

Aelec , Spain’s utilities lobby, representing suppliers such as Iberdrola and Endesa , agreed with the findings that highlighted voltage control deficiencies. Aelec said: “Despite having sufficient resources to guarantee voltage control, REE opted to manage voltage with limited synchronous capacity and an unbalanced geographical distribution, which left the system in a vulnerable situation.”

REE has not responded to requests for comment regarding the findings.