A fierce debate over the future of nuclear energy has resurfaced in Catalonia and across Spain, fuelled by the persistent energy crisis and a critical decision looming for the Spanish government. At the heart of the issue is whether to extend the life of the country’s ageing nuclear fleet or proceed with a planned phase-out by 2035, a choice with profound implications for Catalonia’s energy security.

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The immediate catalyst is a pending decision from Madrid’s Ministry for the Ecological Transition on the Almaraz Nuclear Power Plant in Extremadura. The plant’s owners-Iberdrola, Endesa, and Naturgy-have formally requested a two-year extension to its operational life until 2030. If the government agrees, it could set a precedent for Spain’s six other active reactors. A refusal would signal the definitive start of a shutdown calendar that would see Spain’s last nuclear plant close in just over a decade.

A Tale of Two Energy Grids

The stakes are different for Catalonia than for Spain as a whole. While nuclear power provided a significant 19% of Spain’s total electricity in recent years, Catalonia’s dependence is far greater. The region’s three reactors-Ascó I and Ascó II, and Vandellòs II-collectively generated 56% of its electricity in the same period, making it the backbone of the Catalan grid.

This high dependency places Catalonia in a precarious position as the national debate unfolds. The company that operates the plants, the Asociación Nuclear Ascó-Vandellòs (ANAV), insists its facilities are technically prepared for a longer life.

Catalonia’s Plants “Ready to Continue”

Speaking to the media recently, ANAV’s Director General, Paulo Santos, stated that a ten-year life extension is not a technical problem. However, it would require significant investment of between €90 and €100 million annually to guarantee the plants’ long-term reliability.

“Our three plants have passed periodic safety reviews and are in perfect technical condition. We continue to invest around thirty million euros a year in each unit to continue improving,” Santos affirmed, as reported by Ara Cat.

Santos described the request to prolong Almaraz’s operation as “good news” and confirmed that ANAV’s owners are watching the government’s reaction closely. “We are waiting to see what the reaction from the government is,” he said. “We want the entire nuclear fleet in Spain to continue operating and for the Ascó and Vandellòs plants to also be able to aspire to operate for more years.”

The Economic and Environmental Calculus

Not everyone agrees that extending the life of nuclear plants is the right path. Economist and university professor Mar Reguant argues that nuclear power’s inflexibility poses a major problem for the green transition. Because nuclear reactors cannot be easily switched on and off, they continue to produce power even when there is a surplus of solar and wind generation.

“In Spain, nuclear power means we throw away sun and wind,” she explained, noting that during periods of high renewable output, the excess energy from renewables is effectively valued at zero. Reguant also highlighted a significant “opportunity cost.”

“If investors allocate money to the necessary investments to extend the life of nuclear plants, they will not do so to increase storage (with batteries or pumping stations),” she argued. Given that Catalonia lags behind other regions in renewable generation, this trade-off is particularly stark. Spain has no domestic uranium but abundant sun and wind, resources that could provide true energy independence and make its industries more competitive, Reguant concluded.

A Question of Security

This view is contested by business leaders concerned about grid stability. José Enrique Vázquez, president of the energy commission for the business association Pimec, warns that Catalonia and Spain face a supply problem if gas imports are disrupted.

“If we close the nuclear plants, they will have to be replaced by combined-cycle gas plants, and we will even have to build more,” Vázquez said. He stressed that decommissioning is a one-way street; restarting a closed plant would take an estimated four years. For this reason, Vázquez is calling for an “urgent debate” that he claims “is not taking place at an institutional level.”

The Spanish government now finds itself at a crossroads. Its decision on Almaraz will be a watershed moment, setting the course for the nation’s energy policy and determining whether the 2035 nuclear phase-out remains a firm goal or a flexible target in an era of geopolitical uncertainty.