The drought affecting part of Europe is once again weakening the electricity production of nuclear power plants installed along rivers, the volume of which is becoming scarce. Several reactors have just been shut down in Eastern Europe and France. Explanations.

Published on: 08/04/2026 - 7:41 p.m. Modified on: 08/04/2026 - 7:43 p.m.

This is a consequence of the climate crisis: the drop in the level of rivers weakens the production of electricity from nuclear sources. In France, the two reactors at the Chooz nuclear power plant (Ardennes), as well as a reactor at the Cattenom power plant (Moselle), were shut down on Tuesday August 4 due to a drop in the flow of the Meuse and Moselle, EDF announced.

The country has 57 reactors, which provide nearly 70% of its electricity production. All are located at the edge of a watercourse or on the coast to allow cooling of the installations.

Central Europe's electricity needs under threat

In eastern Europe, the Danube has also seen its level drop, due to the scarcity of precipitation coupled with the heat waves which have been raging since May.

Hungary's only nuclear power plant was almost shut down completely, before engineers managed on Monday to ensure the operation of at least one of the turbines. Never seen before in 44 years of operation.

The Hungarian government plans to limit the energy deficit by calling on large industrial consumers to save and by importing electricity. Households are also encouraged to do without it during consumption peaks.

The challenge goes beyond Hungary: this power station usually provides a third of Central Europe's electricity needs.

The Danube also cools Romania's only nuclear power plant, near Cernavoda.

The authorities had to call on the Romanian navy to keep the site operating. This dynamited rocks in the river bed in order to direct the water towards the power station. One of its reactors nevertheless had to be shut down.

Nuclear installations must be continuously cooled to operate safely. This explains their construction by the sea or near rivers, where they draw significant quantities of water. The water taken is then returned to the environment – ​​after being treated – in full or at more than 90%, depending on the cooling systems.

“France remains hypersurplus”

A shutdown is a matter of water diplomacy: in Chooz, in the Ardennes, the two reactors are shut down under a 1998 Franco-Belgian agreement which provides for the shutdown of French reactors below a certain flow rate of the Meuse. “It’s a water sharing agreement,” summarizes Valérie Faudon, general delegate of the French Nuclear Energy Company (Sfen).

This agreement "specifies that the operation of the production units can be adapted in order to guarantee sufficient water flow for the different users of the river, in France and in Belgium", recalls EDF.

Elsewhere, the shutdowns relate to “compliance with regulations on thermal discharges into water”. These rules, specific to each site, aim to protect the flora and fauna, explains Valérie Faudon.

Certain sites – such as that of Golfech, in Tarn-et-Garonne – are frequently shut down, the water temperature already being above ecological standards upstream of the reactors due to climate change, specifies the Sfen representative.

However, "France remains in a hyper surplus" in electricity production, despite the reactors being shut down, she tempers: at the beginning of August, France has a positive export balance. According to figures from the manager of the French Electricity Transmission Network (RTE), the country even recently broke a record, exporting as much electricity in the first half of 2026 as in an average year.

Europe in search of good energy

In a world threatened by climate change, but ever more energy-intensive, electricity from nuclear power keeps two promises: massive and continuous production, and almost zero CO2 emissions.

However, "we can clearly see that nuclear power is not a solution to combat climate change", objects Roger Spautz, nuclear campaign manager at Greenpeace France and Luxembourg, on the set of France 24.

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The cause is climate change, precisely, and the summer droughts that it aggravates. Because the low water level – namely the lowest level reached by a river in the year – could decline by 15% on average on French rivers by 2050, with more marked declines in the south of the country, according to the Explore2 research program, coordinated by the National Research Institute for Agriculture, Food and the Environment (Inrae).

“In the future, the shutdown of reactors will no longer be a matter of one, two or three weeks as is currently the case, but over much longer periods, during which certain regions will no longer be able to count on their power plants, particularly those located near rivers,” assures Roger Spautz.

To climate challenges, supporters of nuclear power oppose the ability of this technology to adapt. Located in the middle of the American desert in Arizona, the Palo Verde power plant is cooled with treated wastewater from the Phoenix region.

But technical solutions remain limited, argues Paul Dorfman, associate researcher at the Science Policy Research Unit at the University of Sussex and president of the Nuclear Consulting Group, a non-profit institute critical of the sector. He spoke on Tuesday August 4 on the English-speaking set of France 24.

Long sold as a controllable energy, available to order, the atom is becoming a “victim of the climate”, he points out. It in turn is subject to the vagaries of the weather, such as solar or wind power.

Hydroelectricity is not spared either: in Serbia, a dam saw its production divided by five and the country's power stations lost up to 20% of their capacity, due to a lack of a sufficiently high Danube.

Europe, however, is an exception: its CO2 emissions have fallen by 43% since 1990, when global emissions increased by 60% at the same time. Low-carbon energies today provide 72% of its electricity, including 23% from nuclear power alone.

But the share of nuclear power remains stable, while renewable energies increased from 37.4% of European electricity in 2020 to 47.5% in 2024: long based on the atom and dams, the decarbonization of the continent is now driven by the wind and the sun.

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