European report reveals causes of the largest blackout in 20 years in Spain and Portugal: failures in the grid, electrical systems, and renewables.

The European organization ENTSO-e, which groups the electricity network operators of the continent, published on Friday the final report on the blackout that affected Spain and Portugal on April 28, 2025, describing it as the most severe event in the European electrical system in over two decades. Far from a single cause, the investigation concludes that the incident was the result of a complex interaction of multiple factors, which led to voltage increases and a cascading disconnection that ended in a massive blackout. The report was prepared by a panel of 49 international experts, including representatives from electricity operators, regional coordination centers, and European regulatory bodies.

In its conclusions, it points to shared responsibilities among Red Eléctrica, major companies in the sector, renewable energies, and government regulators. Failures in system management One of the critical points identified was the management of the network by Red Eléctrica. According to the report, the use of manual controls on key components hindered an effective response to the speed of the event.

Additionally, the lack of real-time monitoring of reactive power, a key element for the stability of the electrical system, prevented anticipation of the collapse. The analysis also points to major electricity companies—such as Iberdrola, Endesa, and Naturgy—indicating that their conventional generators failed to adequately cover the demand for reactive power, providing less than necessary at the critical moment. In parallel, renewable energies played a significant role in exacerbating the event.

According to the report, many plants operated with a fixed power factor, failing to adapt to voltage variations, which hindered system stabilization. Moreover, several installations automatically disconnected before reaching critical limits, contributing to the domino effect that triggered the blackout. Responsibility of regulators The document also questions the Spanish regulatory framework.

In particular, it notes that the regulations allow for a wider voltage range than in other European countries, which reduces the safety margin before automatic disconnection mechanisms are activated. This condition, according to experts, would have created a conducive environment for the system collapse to occur. Following the analysis, the panel of experts provided a series of recommendations to prevent similar events.

Among them are: Improve real-time control of reactive power Establish stricter criteria and penalties for non-compliance Increase system recovery drills Strengthen communication and remote control systems Adapt regulation to the growing integration of renewable energies The report concludes that the European electrical system faces new challenges in the energy transition, and that it will be crucial to adjust both technical operation and regulation to avoid large-scale crises like the one that occurred in April 2025.