Major Spanish power grid blackout had multiple causes, minister says

The nationwide power grid blackout that hit Spain on 28 April had multiple causes, but inappropriate actions by grid operator Red Eléctrica and some power plants contributed to it. Energy Minister Sara Aagesen said this today while presenting the government’s analysis of the circumstances surrounding the blackout. According to her, the outage was triggered by overvoltage that the grid was unable to respond to. The ministry led by Aagesen will soon put forward measures to strengthen the Spanish grid’s ability to cope with similar voltage fluctuations.

"The blackout on 28 April had multiple causes," Aagesen said at a press conference.

According to her, the blackout was caused by overvoltage that triggered a chain reaction: power generation was disconnected, leading to further generation capacity being disconnected. "The system did not have sufficient capacity available to control voltage," the minister added. Before the complete grid failure, there was an unusual fluctuation "of a local nature", which, among other things, disrupted the grid’s connection and synchronisation with France and the rest of Europe. Aagesen again ruled out a cyberattack as the cause of the blackout.

The minister indicated at the press conference that grid operator Red Eléctrica bore some responsibility for the collapse, having received reports of grid instability from the morning of 28 April. The company had not scheduled sufficient balancing capacity, she said, even though it was its responsibility to do so. Aagesen also said that some power plants that were supposed to help the grid cope with the overvoltage failed to do so, despite being paid for the service. Some plants disconnected from the grid when they should not have, she said.

Aagesen’s ministry will prepare a series of measures to improve the situation in the near future. For example, the authorities will step up oversight to ensure that all parties with an influence on the power grid and distribution fulfil their obligations.

A nationwide power supply outage hit Spain shortly after noon on 28 April. Supplies were not restored across most of the country until late in the evening. The outage also affected neighbouring Portugal.