The Fundación Renovables report finds that the nuclear option makes no economic sense and clashes directly with the renewable and storage development set out in the PNIEC.
The data refute the claim that the nuclear sector bears a high tax burden and show that the taxes intended to cover waste treatment and future dismantling have accumulated a deficit of 5 billion euros.
Madrid, 18 November 2025.- Keeping nuclear power plants operating beyond the closure timetable would have unprecedented economic, social and environmental impacts, while also representing an “illegitimate” alteration of Spain’s energy planning aimed at decarbonising and electrifying the economy. This is one of the central ideas contained in The Future of Nuclear Energy in Spain, Fundación Renovables’ latest report, which analyses and provides data on the implications of extending the operation of Spanish reactors.
From a legal perspective, it should be remembered that extending the life of the Almaraz plant is a discretionary decision of the Government, in line with consolidated case law on the closure of the Garoña plant.
From an economic perspective, there are no universal data proving the cost of refurbishing a reactor to extend its operation. Nevertheless, from the European context we know that this type of work can cost between 25% and 50% of a new plant—with total costs of between 14 billion and 35 billion euros—representing a disproportionate investment when safer, cleaner and more cost-effective alternatives exist.
The data consulted also show that taxes and the ENRESA levy—intended to finance radioactive-waste management—are insufficient even if the closure timetable remains unchanged. According to the 7th General Radioactive Waste Plan, the current levy would have to be multiplied by six to cover real costs, as there is a deficit of 5 billion euros. Extending the life of the plants would worsen this deficit by increasing fuel consumption and waste production. There is a clear risk that all these costs will ultimately be borne by public funds and consumers. These data not only discredit the common argument that the lack of competitiveness of nuclear power in Spain is due to a high tax burden, but also reveal that it should bear a higher tax burden to cover all the externalities associated with its production.
The deficit identified in the report also shows how the problems linked to waste management may become a burden that mortgages the future of coming generations.
It should also be noted that the cost of nuclear energy is considerably higher than that of photovoltaic and wind power. In Spain, nuclear exceeds €65/MWh compared with €24 and €43/MWh for wind and solar PV. Internationally, and as a future investment projection according to the Levelized Cost of Electricity (LCOE) methodology, nuclear stands at $173/MWh, compared with $37/MWh and $70/MWh for the renewable technologies mentioned, excluding nuclear from the merit order as an alternative.
Operational rigidity and incompatibility with renewables
The idea that nuclear power plants do not compete with or displace renewables, but are allied technologies for decarbonising the country, falls under its own weight. The report shows that Spanish reactors are an obstacle to renewable development due to their operational rigidity. It has been proven that, at times of high renewable output, nuclear plants and the lack of storage create grid congestion that forces photovoltaic or wind plants to disconnect. In areas close to Almaraz, a higher percentage of renewable curtailment has been recorded precisely because of this incompatibility with nuclear power and its operational rigidity, which prevents it from adjusting generation to demand and to the needs of the electricity mix.
All of this is compounded by nuclear power’s inability to provide grid stability during overvoltage events. This argument was repeated after the blackout of 28 April; however, the electricity companies that own Spain’s reactors have themselves acknowledged to Red Eléctrica that they do not have the technical capacity to do so and therefore cannot prevent another total blackout. Renewables, by contrast, can act in this direction thanks to grid-forming technology, which is still pending regulation and already works in countries such as Portugal.
The false nuclear renaissance
Fundación Renovables’ publication refutes the idea that the world, and Europe in particular, is experiencing a nuclear boom. From 2010 to 2024, installed nuclear capacity grew by only 1.2% worldwide, from 370.9 GW to 375.5 GW. If we compare renewable growth over the same period, wind and solar PV increased by 262%, from 1,227 GW to 4,448 GW. A total of 87.5 GW of additional nuclear capacity was commissioned during that time, but 78.8 GW was lost through the closure of 105 reactors worldwide.
Looking at European Union countries, the trend is clearly downward, falling from 120 GW of nuclear capacity in 2010 to 97 GW in 2024. The sector therefore experienced a 19.5% decline, mainly due to the closure of German reactors and the stagnation of the French fleet. It should also be noted that active reactors are very old, as is the case in Spain.
In this context, more than 78% of Europe’s reactors are owned by state-owned or state-controlled public companies; 8.2% are public-private consortia; and only 13% of plants are exclusively privately owned. Why? Delays and cost overruns in new reactors, together with the high tax burdens needed to cover waste treatment, fuel and future dismantling, make investment unattractive for private companies.
The narrative of a nuclear revival also includes so-called SMRs, small modular reactors, presented as the future solution that will drive the sector. However, most of them are still in the research phase, with costs above €100/MWh, three times higher than wind or solar PV.
