Extending the closure timetable will slow renewable investment and increase energy curtailment on the grid
Renewables can more than replace nuclear generation after the reactors are closed
Madrid, 21 January 2026.- Extending the lifetime of nuclear power plants beyond the timetable agreed in 2019 means giving up on meeting the renewable targets set out in the National Integrated Energy and Climate Plan 2020 (PNIEC). This is demonstrated by Fundación Renovables’ latest report, which analyses several scenarios showing that keeping reactors in operation blocks the installation of new renewable plants and weakens the competitiveness of existing facilities. The publication complements the first holistic report on the future of nuclear energy in Spain, published in November 2025.
In a future scenario in which all current nuclear reactors extend their operation until 2035, the data show that renewable generation would lose at least 350.8 TWh due to demand saturation between 2028 and 2035. In other words, more than 256 TWh would be lost, equivalent to current annual electricity demand. In this situation, investment in new renewable plants would stop completely, as the technology would become unattractive and uncompetitive, leaving installed capacity practically stagnant until the final closure of the reactors.
Negative prices in the electricity mix would also increase. In 2028, if the closure timetable is maintained, hours with negative prices would be 44.5% higher than in 2025. If reactors extend their lifetime, this figure would rise to 61.4%, making most renewable projects economically unviable.
In a scenario in which the lifetime of plants is extended until 2035 and electricity demand also increases—a likely forecast due to the electrification of mobility, industry and heating/cooling—the consequences remain disastrous for renewables.
The report also refutes the idea that nuclear closure will lead to increased intensive use of fossil fuels and gas burning. The loss of nuclear generation due to the staggered closure of reactors can be more than offset by renewable deployment combined with batteries, even maintaining the current pace of installation. It therefore confirms that the more nuclear there is in the mix, the less renewable capacity there will be, while also disproving the fallacy that backing nuclear power reduces CO2 emissions.
As regards security of supply, the deployment of storage resolves any potential issue, together with its hybridisation with existing renewable projects. In addition, the closure of reactors would benefit technical aspects of the grid, such as voltage control, tasks that cannot be performed by nuclear plants but can be carried out by renewable installations since the beginning of this year.
Therefore, as the data show, continuing with the dismantling plan will not only increase costs for consumers, but will also pose a risk to the continued installation of renewables. Fundación Renovables argues that maintaining the closure schedule is a priority if we are to meet the climate commitments Spain made under the PNIEC.
