Spain successfully restores its total energy supply after a historic nationwide blackout

Spain has fully restored the electricity supply across the entire mainland territory following the largest blackout recorded in its history, an energy collapse that left millions without power on Monday, with effects lasting over 18 hours.

At 7:00 am this Tuesday, Red Eléctrica – the energy manager of Spain – confirmed that the peninsula's energy demand had recovered to 99.95%, and the Ministry for Ecological Transition certified that 100% of the substations in the national electricity system were already operational.

The crisis began at 12:33 PM on Monday with the sudden drop of 15 gigawatts of power – 60% of the national supply at that moment – in just five seconds, causing the cascade disconnection of the main generation sources and an almost complete loss of supply.

Although there was initial speculation about the possibility of a cyberattack, Red Eléctrica has dismissed that hypothesis and points to a combination of technical factors related to excessive dependence on solar energy as the cause of the collapse.

Excessive confidence in photovoltaics is at the center of the debate

According to the initial explanations provided by the company and energy sector experts, the blackout was the result of a severe voltage fluctuation that destabilized the system in a matter of seconds.

The cause, they assert, was the limited presence of technologies that provide "stability" to the electrical system—such as nuclear, hydroelectric, and combined-cycle plants—against an overload of solar generation.

On Monday, over 70% of the demand was being met by photovoltaic energy, a historically high proportion, but one that lacks the technical stability provided by conventional sources.

The failure is believed to have originated in the southwest region of the peninsula, possibly in the community of Extremadura, where there is a high concentration of solar plants.

In the words of the Director of Electric Network Operation Services, Eduardo Prieto, "two almost simultaneous events of generation loss" were identified, which caused fluctuations in the grid and triggered the total blackout.

Photovoltaics, which under normal conditions is considered a cornerstone of the energy transition, collapsed due to its inability to withstand tension during sudden fluctuations.

Pedro Sánchez orders a technical investigation and points to private responsibilities

In light of the extent of the blackout, President Pedro Sánchez announced the establishment of a technical investigation commission that will operate under the National Security Council and will be led by the Ministry for Ecological Transition, with the collaboration of the National Cybersecurity Institute (INCIBE).

An independent report has also been requested from the European coordination group for electricity of the European Commission.

Sánchez, who did not rule out any hypothesis regarding the cause of the event, emphasized that "responsibilities will be demanded from the private operators" involved, including Red Eléctrica, and urged caution before accepting the technical explanation provided by the company as definitive.

"We respect your preliminary conclusions, but the Government needs a comprehensive and verified view of the facts," he noted.

The president insisted that the event occurred in a context of operational normalcy and high energy availability, stating that "nothing indicated a crisis of this magnitude could occur."

Impact on services and progressive recovery

The blackout severely affected key sectors such as transportation, telecommunications, and industry.

More than 48,000 Renfe passengers (the main railway transport company in Spain) were unable to travel on Monday, although by Tuesday the company had already transported over 12,700 people and was offering refunds and ticket changes at no cost.

At the airports, operations were maintained at 93%, and only one long-haul flight (Barcelona–Philadelphia) was canceled.

Telecommunications operators also reported significant disruptions, and thousands of customers were without service well into the early morning hours.

The system needs a new balance

This blackout has rekindled the debate about the need for a balanced energy mix. Excessive reliance on intermittent renewable sources like solar, without adequate backing from firm generation or advanced storage systems, has left the country in a vulnerable position.

The sector warns that decisions such as the premature closure of nuclear plants and the limited use of combined cycles and reservoirs are leaving the system without buffers against extreme events.

"Red Eléctrica miscalculated the risks," sources from the energy sector reported, noting that the blackout could have lasted more than 24 hours if the transformers had been damaged.

The lesson, experts say, is that even a technologically advanced system like Spain's is not free from faults when the balance of energy sources is disrupted.

The full picture of what occurred on Monday has yet to be revealed, but the incident has already marked a turning point in the country's energy debate.

Frequently Asked Questions about the Massive Power Outage in Spain