Almaraz Nuclear Power Plant
Why is the Almaraz Nuclear Power Plant key to Extremadura and the Spanish electricity system?
The Almaraz Nuclear Power Plant is located in the Spanish municipality of Almaraz (Cáceres, Extremadura), next to the artificial reservoir created for its cooling, on the Arrocampo stream, a tributary of the River Tagus, at the Torrejón dam.
Almaraz I and II nuclear power plant
Key facts about the Almaraz Nuclear Power Plant
- The Almaraz Nuclear Power Plant covers around 7% of Spain's annual electricity demand (equivalent to the consumption of four million Spanish households)
- Its two units produce more than 15,000 GWh per year and avoid the emission of 5.5 million tonnes of CO₂.
- The Almaraz Nuclear Power Plant operates to the highest international safety standards, and the World Association of Nuclear Operators re-certified its highest category of excellence in 2025.
- With more than 4,000 direct jobs, the Almaraz plant is one of the main economic and social drivers of Extremadura
The plant's site covers 1,683 hectares, in a location ideally suited due to its seismotectonic, geological, hydrological and climatic characteristics. It comprises two units: Almaraz I and Almaraz II, each with a capacity of 1,051 MWe.
Both nuclear reactors, which have been in commercial operation since 1983 and 1984 respectively, are authorised to operate until 1 November 2027 (Almaraz I) and 31 October 2028 (Almaraz II), in accordance with the current nuclear phase-out schedule in Spain. Iberdrola España owns 52.7% of the plant.
Technical characteristics of the Almaraz Nuclear Power Plant
The Almaraz Nuclear Power Plant consists of two pressurised water reactors (PWRs), using technology from the US company Westinghouse.
Amaraz I nuclear power plant (Cáceres – Extremadura)
Location: Almaraz de Tajo
Commissioning: 1983
Installed capacity: 1,049.40 MW
Almaraz II nuclear power plant (Cáceres - Extremadura)
Location: Almaraz de Tajo
Commissioning: 1984
Installed capacity: 1,044.50 MW
The Almaraz Nuclear Power Plant operates to the highest international safety standards, and the World Association of Nuclear Operators (WANO) awarded it the highest category of excellence in 2025, which attests to its exemplary performance in safety and operation.
In addition, the plant is investing €50 million a year to improve, upgrade and modernise its equipment and facilities, maintaining them in optimal technical condition and safely extending its operational life. This is in line with international practice, where twin reactors such as those at the North Anna Nuclear Generating Station have been authorised by the US regulator to operate for up to 80 years.
How does the Almaraz Nuclear Power Plant work and how much energy does it produce in Spain?
Nuclear power stations generate electricity through the fission of uranium, which takes place inside the reactors. Nuclear fission occurs when the nucleus of heavy atoms, such as uranium, is bombarded with neutrons until it splits into two or more smaller nuclei. This splitting (fission) releases an enormous amount of energy in the form of heat and radiation. Nuclear power stations control this process and convert this nuclear energy into electricity via a steam turbine coupled to an electric generator.
Nuclear energy is considered a source of energy that does not emit greenhouse gases, is stable and reliable as it does not depend on weather conditions and provides inertia to the electricity system, as it is synchronous energy that contributes to the frequency stability and safety of the electricity system.
In 2025 the Almaraz Nuclear Power Plant supplied around 7% of Spain's annual electricity demand, equivalent to the annual consumption of four million households in Spain.
Together, Almaraz I and Almaraz II produced a total of 15,370 GWh in the same year and prevented the emission of 5.5 million tonnes of CO₂ into the atmosphere. What’s more, it is the generation facility that has contributed the most energy to Spain's electricity system since it entered operation, with a cumulative gross electricity production of more than 640,000 GWhby the end of 2025.
15,370
Total GWh generated in 2025
5.5
millions of tonnes of CO₂ avoided
640,000
Cumulative gross electricity generation in GWh
Economic and social impact of the Almaraz Nuclear Power Plant in Extremadura and Spain
The Almaraz Nuclear Power Plant is the main socio-economic driver in its region and one of the largest industries in Extremadura, generating employment, business dynamism and tax revenue.
The plant provides highly skilled, long-term jobs as well as acting as a catalyst for other industries. Around 4,000 people work at the plant plus a further 1,000 who join the workforce for each refuelling operation (there have been 29 refuelling operations since its foundation). Its operations also support an extensive network of service companies and suppliers, with the business structure of the surrounding area shaped by the plant's presence.
Currently, the nuclear decommissioning schedule in Spain provides for the closure of this facility on 31 December 2027 and 31 December 2028 for each of its reactors respectively. The closure of the Almaraz Nuclear Power Plant would have a very significant socio-economic impact on the surrounding area, leading to the loss of many direct and indirect jobs, a substantial reduction in economic activity and added value in the region as well as a fall in household income.
This could lead to structural effects such as the exodus of the working-age population, demographic ageing and the weakening of the local business fabric as well as lower tax revenue for the authorities. All of this in a context where the potential for replacement by new economic activities is uncertain.
In this regard, on 1 October 2025 the plant's operator, Centrales Nucleares Almaraz-Trillo AIE (CNAT), officially requested from the Ministry for Ecological Transition and the Demographic Challenge (MITECO) an extension of the operating licence for the two units of the Almaraz Nuclear Power Plant until June 2030. Almaraz meets all the requirements of the Periodic Safety Review approved by the Nuclear Safety Council (CSN) in 2020, which remains in force until 2030.
The key role of the Almaraz plant for Spain
The Almaraz Nuclear Power Plant is now a strategic energy infrastructure for Spain for three fundamental reasons:
- It guarantees a stable, predictable and competitive electricity supply, which is essential for the functioning of the economy and the security of the Spanish electricity system.
- It makes an irreplaceable contribution to decarbonisation, continuously generating emission-free energy and avoiding reliance on fossil fuel technologies at times of geopolitical tension
- It acts as an economic and social pillar for its local area, sustaining high-quality, long-term employment, industry and territorial cohesion in a particularly vulnerable region.
Doing without this capacity would mean Spain losing a reliable, decarbonised and competitive generation source for which there is currently no fully mature equivalent from a technical and economic point of view.
In the current energy and geopolitical context, the continued operation of Almaraz is not merely an option but a key strategic decision to ensure energy security, industrial competitiveness and the fulfilment of Spain's climate targets.
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