Home Europe Granada Substation Fault Identified As Cause Of Spain-Portugal Blackout

Granada Substation Fault Identified As Cause Of Spain-Portugal Blackout

Several investigations are looking into the power outage, but it is the first time Spanish authorities have pointed to a specific origin.
People walk along a shopping street without electric lighting as police cars patrol to prevent theft and looting in the stores during a power outage which hit large parts of Spain, in Ronda, Spain, April 28, 2025. REUTERS/Jon Nazca/File Photo

A sudden power loss at a Granada substation, followed by rapid failures in Badajoz and Seville, caused a massive blackout across Spain and Portugal on April 28, Spain’s energy minister said on Wednesday.

Energy Minister Sara Aagesen told lawmakers that the three initial incidents, whose cause has yet to be determined, led to a generation loss of 2.2 gigawatts of electricity, which triggered a series of grid disconnections.

Several investigations are looking into the power outage, but it is the first time Spanish authorities have pointed to a specific origin. Establishing the cause of the outage will take time, and there will likely be no simple answers to what appears to be a complex issue, Aagesen said.

“We are analysing millions of pieces of data. We also continue to make progress in identifying where these generation losses occurred, and we already know that they started in Granada, Badajoz and Seville,” Aagesen said.

She said the government’s investigation is also looking at reports by operators of volatility in the days before the blackout and is examining excessive voltage as one possible cause for the loss of generation.

Investigators, Aagesen said, had ruled out any cyberattack on grid operator REE, an imbalance in supply and demand or insufficient grid capacity.

She also denied suggestions by some opposition lawmakers that the government had received and ignored warnings from experts that a major blackout could occur, adding that it would be premature to attribute responsibilities until it’s known what happened that day.

“There was no alert, no warning,” she said.


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Spain’s use of renewable energy as an increasing part of its electricity generation has come under scrutiny since the blackout, as has its plan to phase out nuclear energy by 2035.

‘Grid Inertia’

Critics have said that one possible contributor to the outage may have been a lack of so-called “grid inertia” because of the relatively small share of nuclear and fossil fuel generation in Spain’s power mix.

Aagesen defended the government’s energy policy, saying that renewables have lowered bills for households and businesses and will allow Spain to attract more investment while providing more energy autonomy at a time of geopolitical instability.

Spain’s electricity system continues to use the same level of renewables as it did before and during the outage, she said.

“A mix with more renewables reduces external risks. It enables us to anticipate, adapt to, and respond quickly to any eventuality.”

Aagesen signalled openness to extending the life of nuclear plants, but only if operators could guarantee their security and acceptable prices for consumers, and if this could be shown to contribute to the security of supply.

(With inputs from Reuters)