The blackout that hit the Iberian Peninsula on 28 April 2025 was caused by excessive voltage in the transmission grid, which set off a chain reaction. A cyberattack has been ruled out as the cause. This information comes from an investigation report presented yesterday by Sara Aagesen, Spain’s Vice-President and Minister for Ecological Transition and Demographic Challenges.
The report states that the Spanish transmission system operator, Red Eléctrica, took several voltage-stabilising power plants offline the day before the blackout. Additionally, several control power plant operators did not respond appropriately to instructions from the grid operator to reduce voltage. Some even produced reactive power, exacerbating the problem.
Some power plant shutdowns occurred before the legally prescribed voltage limits were exceeded, while others occurred after these limits had been exceeded in an attempt to protect the plants. Once the chain reaction began, the electrical system’s usual protective measures were unable to stop or contain the process. Some of these measures, such as load shedding, actually contributed to the critical voltage increase.
The government has announced that it will adopt a package of measures to increase the robustness of the power grid at the next cabinet meeting.
»In summary, there was a lack of resources for voltage regulation. This was either because the resources were not planned adequately, were insufficient, or both. However, this was not due to a lack of resources in the country, as there were more than enough power plants to meet demand.«
© PHOTON
