On April 28 2025, a major power outage was recorded as a large-scale crisis that paralyzed daily life in Spain, Portugal and south-western France. In major cities such as Madrid, Barcelona and Lisbon, airports, train systems, traffic lights and even the internationally organized Madrid Open Tennis Tournament were affected. The disruption to millions of homes and businesses prompted governments and energy operators to organize emergency cabinet meetings to respond to the situation. Such incidents again highlight the structural weaknesses the European Union (EU) faces in energy security, grid integration and the renewable energy transition.
According to the statements made, the main cause of the outage was defined as ‘abnormal vibrations of atmospheric origin’ occurring in high voltage lines as a result of extreme temperature changes in the interior of Spain. This resulted in small parameter changes in the 400 kV transmission lines causing an imbalance in the system frequency, leading to a cascade of blackouts that can be characterized as ‘rolling blackouts of power plants’. As Georg Zachmann from Bruegel pointed out, when the frequency of the grid dropped below 50 Hz, automatic circuit breaking mechanisms were activated, triggering cascading blackouts in other countries in Europe.[1] Another explanation is a technical explanation that ‘the change in conductor parameters due to temperature change causes frequency imbalance in the system’.
Spain’s energy structure can be summarized as approximately 43% of the electricity consumed in the country is provided by renewable sources such as wind and solar, with nuclear energy contributing 20%.[2] However, due to the nature of renewable energy, fluctuations in production increase the need for new technological solutions in addition to classical methods in order to maintain the balance of the grid. Traditionally used gas turbines alone are no longer considered sufficient for uninterrupted renewable energy generation; therefore, investments in smart grids, energy storage systems and advanced power electronics solutions should be increased.
Although the EU has adopted policies to increase energy integration and solidarity through the 2009 Lisbon Treaty, this has become more evident in times of crisis in countries such as Spain and Portugal, where systems are relatively weakly connected to the main European network. In particular, such large-scale outages signal the need for a rethink on energy co-operation and grid resilience among Member States. As the EU aims to achieve its 2050 carbon neutrality target under the Green Deal, it must strengthen infrastructure investments and international interconnections to ensure system security and uninterrupted energy supply.
In particular, the emergency response processes of the blackout in Spain and Portugal have once again demonstrated the importance of the coordination of national governments in times of crisis. Spanish Prime Minister Pedro Sánchez, in a national address, called for caution in informing the public, stating that ‘authorities should not give room for speculation; citizens should receive information through official channels’.[3] Similarly, safety council meetings between authorities and the employment of emergency response teams are important steps to minimize the disaster.
In addition to domestic energy links, interconnectors increase international solidarity; assessments that links with France ‘slowed the chain spread of the problem and helped the system to recover’ point to the two-way effect of international systems.[4]
Nevertheless, it should be borne in mind that such international interconnections can also create risks, given that in the past, in the case of Italy in 2003, a hydroelectric line failure led to a 12-hour blackout, or in 2006, an overload in Germany spread to other European countries.[5]
The blackout had a profound impact not only at the technical and political levels, but also at the social level. In Madrid and Barcelona, disruptions in shopping centers, public transport networks and even the suspension of routine operations in hospitals significantly disrupted people’s daily lives. According to Reuters, images such as ‘the suspension of routine operations in hospitals and the emptying of supermarket shelves’ show the devastating effects of the blackout.[6]Moreover, the fact that banking systems are ‘functioning properly’ through back-up systems indicates that the financial infrastructure also needs assurance mechanisms that are activated in times of crisis.
On the Portuguese side, disruptions in water supply and panic purchases of emergency supplies emphasize the importance of issues that directly affect the living standards of the population.[7]
While the disabling of traffic lights and the disruption of metro and train services caused serious disruptions in urban transport, the efforts of local governments to take urgent measures played a decisive role in the process of re-commissioning the network.
In conclusion, this large-scale blackout in Spain, Portugal and south-western France has revealed significant shortcomings in the EU’s energy security strategy. Both the risks of the renewable energy transition and the vulnerabilities of cross-border grid integration suggest that the EU needs to undertake technological, political and infrastructural reforms to prevent similar crises in the future.
While realizing the environmental objectives of the Green Deal, the EU should also strengthen system security measures to guarantee uninterrupted energy supply. Increasing international cooperation, modernizing grid technologies, deploying new energy storage and balancing technologies are critical steps to prevent such large-scale crises. In this context, a more holistic approach to energy policy is essential for maintaining both economic and social stability.
[1] Jasper Jolly, “Spain and Portugal power outage: what caused it, and was there a cyber-attack?”, The Guardian, https://www.theguardian.com/business/2025/apr/28/spain-and-portugal-power-outage-cause-cyber-attack-electricity, (Date Accessed: 28.04.2025).
[2] Jack Burgess and Neha Gohil, “Spain declares state of emergency, as Portugal struggles with power cut transport chaos”, BBC, https://www.bbc.com/news/live/c9wpq8xrvd9t (Date Accessed: 28.04.2025)
[3] From the same source.
[4] “Huge power outage brings parts of Spain and Portugal to standstill”, Reuters, https://www.reuters.com/world/europe/large-parts-spain-portugal-hit-by-power-outage-2025-04-28/, (Date Accessed: 28.04.2025).
[5] Ibid.
[6] Ibid.
[7] Antoinette Radford, Rob Picheta and Elise Hammond, “Electricity supply slowly returning after massive Spain and Portugal power outage”, CNN World, https://edition.cnn.com/world/live-news/power-outages-blackout-spain-portugal-04-28-25/index.html, (Date Accessed: 28.04.2025).
