Spain’s electrical grid experienced instability and supply cuts weeks before the historic blackout that plunged the Iberian Peninsula into darkness. Experts warn about the system’s fragility amid the energy transition.

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Spain Restores Power Supply After Major Blackout

As the Spanish government and judiciary investigate the causes of the massive blackout that paralyzed Spain and Portugal, new information emerges about anomalies in the electrical grid prior to the event. The historic outage on April 28 left millions without power and exposed the vulnerability of the energy infrastructure during the country’s transition to renewable sources.

Weeks before the blackout, Spain’s electrical grid was already showing signs of instability. On April 22, a voltage surge caused substation disconnections, stranding ten high-speed trains near Madrid and halting operations at Repsol’s Cartagena refinery. Antonio Turiel, a researcher at the Spanish National Research Council (CSIC), warned that the grid experienced significant instability in the days leading up to the collapse. However, neither Red Eléctrica Española (REE) nor the Ministry of Energy responded to requests for information, maintaining secrecy amid the crisis.

Energy Transition Under Pressure

The energy crisis occurs amid Spain’s accelerated transition to renewables. The country aims to phase out coal, gas, and nuclear plants, shifting toward solar and wind power. However, experts caution that the high penetration of renewables, without adequate storage and traditional generation backup, increases grid fragility when facing frequency and demand fluctuations. Automatic protection mechanisms designed to prevent equipment damage can disconnect generators in a cascade, amplifying the risk of massive blackouts.

El secretario de Estado de Energía, @j_groizard se reúne con representantes de @RedElectricaREE para avanzar en el análisis de la interrupción de suministro del pasado lunes 28 de abril. pic.twitter.com/pwr8eOyZwg

— Transición Ecológica y Reto Demográfico (@mitecogob) May 1, 2025

The text reads: The Secretary of State for Energy, @j_groizard, is meeting with representatives of @RedElectricaREE to advance the analysis of the supply interruption that occurred last Monday, April 28

Progressive sectors and social organizations demand greater transparency in grid management and a public audit into the blackout’s causes. They urge the state to strengthen public control over the energy system and prioritize investment in resilient infrastructure to guarantee the right to energy and energy sovereignty against private interests. The crisis has reopened debate on the ecological transition model, highlighting the need for democratic and just planning that does not leave citizens exposed to energy insecurity.

“The crisis is not over,” warned President Pedro Sánchez, reflecting concern about system stability and the urgency of structural responses.

The 2025 blackout is a wake-up call about the challenges of the energy transition and the importance of reinforcing public control and social participation in managing strategic common goods like electricity.

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