Catalonia’s three nuclear reactors produced nearly 60% of the region’s electricity in 2025, cementing their role as the backbone of the local energy grid even as a national phase-out looms. The plants generated a combined total of 22,800 Gigawatt-hours (GWh), accounting for 58.8% of all energy produced in the autonomous community last year.

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Crucially, this substantial output came from the nuclear power stations of Ascó (units I and II) and Vandellòs (unit II), all located in the province of Tarragona. The Asociación Nuclear Ascó-Vandellòs II (ANAV) operates these facilities. They are critical components in the wider context of energy production in Spain, consistently providing a stable, high-volume source of power to the grid managed by Red Eléctrica de España.

A Breakdown of Production

The total production figure of 22,800 GWh demonstrates the immense capacity of the Catalan nuclear fleet. According to the individual production data for 2025, Ascó I was the most productive unit, generating 7,991.3 GWh. It was followed by Vandellòs II with 7,392 GWh and Ascó II, which produced 7,280.6 GWh.

Furthermore, this consistent performance not only ensures energy stability for Catalonia’s industries and households but also has a significant environmental impact. According to figures reported by local newspaper Diari Catalunya, the electricity generated by these plants in 2025 prevented the emission of an estimated 8.4 million tons of CO2 equivalent. Proponents of nuclear energy use this contribution as a key argument in the ongoing debate about Spain’s transition to a fully renewable grid.

However, despite their current dominance in Catalonia’s energy mix, the future of the Ascó and Vandellòs plants is finite. Spain’s national plan aims to phase out nuclear power entirely over the next decade, and these plants are subject to it. The Ministry for the Ecological Transition grants operating licences, which the Nuclear Safety Council (CSN) oversees for safety. These licences have set expiration dates.

The current schedule for shutdown is as follows:

  • Ascó I: Licence expires in 2030
  • Ascó II: Licence expires in 2032
  • Vandellòs II: Licence expires in 2035

This timeline presents a formidable challenge for Catalonia. With over half of its electricity currently generated by these three reactors, regional and national authorities must plan for their replacement to avoid a significant energy deficit. The debate revolves around whether renewable sources like solar and wind can scale up quickly enough to fill the gap left by the nuclear fleet’s consistent, 24/7 power.

For now, the 2025 figures underscore a fundamental reality of the current energy landscape: Catalonia’s grid is powered, overwhelmingly, by nuclear energy. As the clock ticks towards the planned closures, the question of what comes next will become increasingly urgent for policymakers and citizens alike.