The real causes of the massive blackout in Spain on April 28, 2025

On 28 April 2025, Spain, together with Portugal and parts of France and Andorra, suffered a massive blackout that paralyzed much of the critical infrastructure, from public transport to telecommunications services. This event, one of the most significant in recent European history, left millions of people without electricity, affecting the operation of airports, meters, hospitals and communication systems. Although the authorities have ruled out a cyber attack as the main cause, the investigations point to a combination of technical and environmental factors. This article analyses the real causes of the blackout, based on information from reliable sources, and explores the implications of this electrical collapse.

Causes of the blackout

The blackout of April 28, 2025 was a complex event, a result of multiple factors that converged to destabilize the electrical network of the Iberian peninsula. The main causes identified are as follows:

1. European electricity network failure: According to the Portuguese operator Nacionais Energy Networks (REN), the blackout was caused by a problem in the Spanish electricity network, which caused an automatic disconnection of the Iberian network of the European electricity network at 12: 38. This ruling is attributed to a «induced atmospheric vibration» in the high voltage lines (400 kV) in Spain, possibly caused by extreme weather conditions, such as sudden temperature fluctuations and high humidity. These conditions generated instability in the transmission lines, which triggered a cascade collapse.
2. Overdependence on renewable sources: Some sources suggest that the Spanish electricity network, which is largely dependent on renewable sources such as wind and solar, faced difficulties in maintaining stability during peak demand. The reduced participation of thermal and nuclear power plants at the time of the blackout may have limited the system's ability to respond to unforeseen fluctuations. This generated speculation about mismanagement by the Red Eléctrica operator, although it has not been officially confirmed.
3. Disconnection of the European network: The French TEN operator reported that the Iberian network was disconnected from the European continental network, resulting in a loss of approximately 15 gigawatts of power in Spain in a matter of seconds, equivalent to more than half of the country's electricity demand at that time. This disconnection may have been an automatic measure to protect the European network, but it exacerbated the crisis on the Iberian peninsula.
4. Adverse climatic conditions: Preliminary reports by Portuguese media and electric operators point to a «rare atmospheric phenomenon» as a trigger. The extreme temperature fluctuations in Spain, combined with high humidity, may have caused vibrations in the high voltage lines, a phenomenon known as «galopeo» of cables, which destabilized the network. Although the exact magnitude of this phenomenon has not been confirmed, electric operators consider it a probable cause.
5. Lack of coordination and maintenance: Some critical analyses, such as those shared on platforms such as X, suggest that the blackout could have been avoided with better electrical network management. The «black boxes» The Spanish electricity system indicated that the problem began to be managed since 10 a.m., but no preventive measures were taken in time. The lack of adequate maintenance on high-voltage lines and insufficient coordination between European operators could also have contributed to the collapse.

Impact of the blackout

The April 28 blackout had devastating consequences in Spain and Portugal:

• Transport: In Madrid, the metro and the nearby trains were paralyzed, leaving thousands of passengers stranded. Airports, such as Barajas, suspended operations, and high-speed trains stopped their service throughout the country.
• Communications: The interruption of electricity affected mobile and Internet networks, leaving millions without access to communication services. This made it difficult to coordinate emergencies and generated chaos in cities.
• Trade and health sector: The shops, forced to accept only cash, and the hospitals, which were dependent on support generators, faced great difficulties. In Madrid, the La Paz hospital reported operational problems due to a lack of energy.
• Daily life: The traffic lights ceased to function, causing massive jams in cities such as Madrid and Barcelona. Citizens faced interruptions in basic services, from ATMs to electronic payment systems.

The blackout also affected high-profile events, such as the Madrid Tennis Open, where spectators had to leave the facilities in the dark.

Response and recovery measures

The authorities and electrical operators reacted quickly to mitigate the impact:

• Supply restoration: Red Eléctrica, the Spanish operator, activated emergency protocols and managed to restore supply by 99% by the morning of April 29, starting with hospitals, airports and other critical infrastructure. The collaboration with France and Morocco made it possible to stabilize the network in the northern and southern regions of Spain.
• Ongoing research: The Spanish Government, led by Pedro Sánchez, established a crisis committee to investigate the causes of the blackout. Sánchez ruled out speculation about cyber attacks and asked to avoid disinformation, although no definitive explanation has been provided.
• International support: The President of the European Commission, Ursula von der Leyen, coordinated efforts with the Spanish and Portuguese authorities to monitor the situation. Ukraine offered to share its experience in managing energy crises, resulting from Russian attacks on its infrastructure.
• Long-term measures:: Electric operators are assessing infrastructure modernization to prevent future collapse, including greater resilience to extreme weather conditions and better integration of renewable sources.

Critics and disputes

The blackout generated criticism of the Spanish Government and Red Eléctrica for the lack of transparency and preparation. Some X users accused President Sánchez of knowing the vulnerabilities of the system from hours before the collapse, without taking preventive measures. Others noted an alleged mismanagement of the transition to renewable energy, arguing that the low participation of thermal and nuclear power plants weakened the stability of the network. However, these claims have not been corroborated by official sources and should be treated with caution.

In addition, the declaration of emergency in regions such as Madrid, Andalusia, Extremadura and Murcia reflected the gravity of the event, but also generated criticism for the slow initial response.

Conclusion

The massive blackout of 28 April 2025 in Spain exposed the vulnerabilities of the European electricity infrastructure, particularly on the Iberian peninsula. Although the exact causes are still under investigation, the evidence points to a combination of a rare atmospheric phenomenon, fluctuations in the electricity network and a possible lack of coordination in system management. This event highlights the need to modernize infrastructure, improve resilience to extreme weather conditions and ensure a balanced energy transition. As the world is increasingly dependent on interconnected systems, events like this serve as a reminder of the importance of international preparedness and cooperation to face energy crises.

Sources

• BBC News
• Policy
• Forbes Ukraine
• CNN Portugal
• El Pais
• Sky News
• Public
• X post from @ PabloFuente