Repsol Warned Clients of Shutdown Days Before Historic Spanish Blackout

Repsol, one of Spain’s largest energy companies, notified major clients five days ago about an “unexpected shutdown due to technical problems with the power supply” at its Cartagena refinery. The disruption, attributed to a severe electrical failure outside the plant’s control, triggered a force majeure clause, according to a letter dated April 24 accessed by El Mundo.

According to industry sources, the refinery’s automatic safety systems were activated after detecting grid imbalances. Once these safety mechanisms are triggered, operations cannot resume until the grid is fully stabilized — a protocol that also played out during the historic blackout that plunged much of Spain into darkness.

The incident at Repsol’s refinery occurred on April 22, the same day Spain’s Minister of Transport, Óscar Puente, blamed “excessive tension in the electrical grid” for high-speed rail disruptions between Chamartín and Pajares, linking Castilla y León and Asturias. Puente even posted a screenshot from Red Eléctrica showing a stressed national grid — an image eerily similar to the data recorded during the later full-scale blackout.

Red Eléctrica later confirmed that Monday’s nationwide outage was caused by a major imbalance between electricity supply and demand, triggered by a significant loss of generation that the system could not absorb. The resulting collapse, unprecedented in Spain’s history, is still being resolved as the grid slowly returns to normal. The first warning signs included severe voltage fluctuations around 12:30 PM, according to Red Eléctrica, though the public company has so far avoided specifying which energy sources failed.

Structural Issues Behind the Blackout

A review of Spain’s electrical grid over the past week shows a growing pattern: excessive solar generation during peak hours regularly surpasses demand. Industry experts have long warned about this risk, which has forced Red Eléctrica to curtail production at multiple solar farms to maintain balance.

Maintaining 24/7 alignment between electricity generation and consumption is critical for grid stability. However, the surge in renewables — particularly solar — during peak hours is making that task increasingly difficult. With Spain’s energy mix heavily reliant on wind and solar, two inherently intermittent sources, the risks of grid instability are rising, driven by the government’s energy transition roadmap under the National Energy and Climate Plan (PNIEC).

According to sources from a major international oil and gas trading firm, invoking a force majeure clause for refinery product deliveries is extremely rare — something that “happens maybe once every 20 years” and usually only under extreme events like natural disasters or explosions.

This unusual situation highlights broader vulnerabilities in Spain’s critical infrastructure. In just one week, two significant mismatches between electricity supply and demand have disrupted critical sectors, including energy and transportation.

A senior energy executive warned: “In a system like Iberia’s, which is poorly interconnected with the rest of Europe, the growing dominance of solar and wind must be balanced with flexible technologies if the aim is to replace gas and, potentially, nuclear energy. Otherwise, natural imbalances will continue to destabilize the grid.”