Contribution of nuclear energy in Spain in 2024 and performance of Spanish nuclear power plants during the national blackout on April 28

Nuclear Results report for 2024

Spanish nuclear power plants generated 52,390.75 GWh net in the past year, representing 19.98% of the total net electricity production. With a net installed capacity of 7,117 MW, nuclear energy managed to become the second largest source of electricity production in Spain, as highlighted in the annual report "Nuclear results for 2024 and future perspectives."

Additionally, nuclear electricity accounted for 26.01% of all CO₂-free electricity generated in Spain in 2024. This underscores its strategic role in the decarbonization process and reaffirms its importance in facing environmental and energy challenges. It is worth noting that the large turbines and generators in nuclear power plants provide rotating power and inertia to the grid, as they are heavy synchronous machines that help stabilize voltage and frequency.

Once again, Spanish nuclear power plants have operated under the highest standards of quality and safety thanks to the commitment and experience of the Spanish nuclear industry and its professionals. They are fully prepared, from a technical standpoint, for long-term operation. However, there is still a demand to reduce the excessive tax burden on nuclear power plants, which worsened due to the 30% increase in the Enresa tax applied in 2024.

You can view the full report here (in Spanish), along with graphics and charts on nuclear production in Spain and by country here.

Response of the nuclear power plants during the national blackout

On April 28, four nuclear reactors (Almaraz II, Ascó I & II, and Vandellós II) were operational before the blackout took place. Three units were offline: Trillo for refuelling and Almaraz I and Cofrentes due to market conditions, as their operation had not been required by the Red Eléctrica de España (the national electricity company) due to technical constraints.

As a result of the loss of external power supply caused by the blackout, the operating reactors shut down automatically, and safety systems were activated to maintain a safe shutdown.

According to operational and design specifications, independent diesel generators started up automatically and powered the necessary systems to keep the plants in safe shutdown conditions, as reported by the Nuclear Safety Council (CSN). All safety systems functioned correctly, and Internal Emergency Plans were activated.

As external power was gradually restored in the plants, the independent diesel generators were disconnected and the Emergency Plans were deactivated, with no impediment to restoring normal operation of the electrical system and service recovery plans.

The nuclear power plants acted according to their design and always remained stable and safe. During the incident, the Nuclear Safety Council activated its Emergency Response Organization and remained continuously informed while monitoring the status of the plants. The reactors are now resuming production after completing all corresponding safety checks, reconnecting to the grid as instructed by the System Operator or when matched in the electricity market.