Berlin, September 21, 2026
The scorching summer of 2026 took many casualties, most tragically tens of thousands of innocent human lives. However, one heat victim we will not mourn is the longstanding myth of nuclear power’s reliability. At present, nuclear energy can no longer be considered a stable power source. Nuclear power plants (NPPs) rely on large quantities of water for cooling. When water becomes scarce, nuclear power’s output is in jeopardy. Estimates indicate that a nuclear reactor requires between 1,514 and 2,725 liters of water per megawatt. In times of global warming, water scarcity is the Achilles’ heel of nuclear power plants.
The recent evidence is clear. In France, Hungary, Romania, and Switzerland, the rivers were too dry and too warm to provide the cooling water NPPs desperately needed. As a result, numerous nuclear reactors across Europe had to be ramped down and even shut down. The nuclear energy concept, so highly touted by lobbyists and right-wing populists, failed to deliver in Europe. No continent is heating up faster than Europe right now. Anyone who speaks of safe, stable nuclear energy is denying the reality of climate change.
Water Shortage Halts Nuclear Power in France
In France, several heat waves over the summer had dramatic consequences. Parts of the country recorded temperatures exceeding 40 degrees. Unbearable heat claimed the lives of thousands of people and led to agricultural droughts, massive wildfires, and a decline in tourism.
Such temperatures also have consequences for the nuclear power supply. In June 2026, some of France’s nuclear power plants were forced to shut down. By July, 23 of the 57 nuclear power plants were offline, and by August, that number had risen to 27. This resulted in a 20% loss of nuclear power generation due to the severe weather events. If river levels are too low to draw cooling water, or if the water is too warm to be discharged back into the river, the only option is to shut down the plant.
Another problem plagued NPPs along the French coast. Rising sea temperatures and other environmental changes are leading to an overpopulation of jellyfish which clogged the plants’ pumps as they were drawn in. As a result, two reactors at the Gravelines NPP on France’s northern coast were completely shut down at the end of August 2026. Monitoring and detection systems had to be set up.
Hungary
On August 2, 2026, the time had come. For the first time in 44 years, Hungary’s sole nuclear power plant had to be shut down. The unprecedented heat wave and low water levels left the Danube nearly dry. The Paks NPP accounts for about one-third of Hungary’s electricity needs. It wasn’t until late August that the reactors could resume full-capacity operation. Before that, however, the water level of the Danube had to be regulated and a river weir constructed. Welcome rainfall also helped alleviate the situation. The massive outage had economic consequences for the country. The carmaker Mercedes, for example, announced a three-week production shutdown.
Romania
The Danube’s low water levels also caused problems at Romania’s only NPP, Cernavodă. As a result, one of the two reactors was shut down at the end of July. To keep the second unit running, the navy blasted a rock to divert more water to the power plant. But that was only a temporary solution, and on August 13, operations were completely suspended. Under normal circumstances, Cernavodă covers about 20 percent of Romania’s electricity needs. As of September 8, the water shortage had not been resolved, and the nuclear power plant remains shut down.
Meanwhile, the Romanian government is facing the need to reassess its energy strategy. The original plan was to extend the operating life of the nuclear power plant’s 700-MW Unit 1 by 30 years through a modernization of the facility. This requires support from the European Union—specifically, financing from the European Investment Bank. EIB intends to contribute 800 million euros; the total cost of the project is estimated at 3,200 million euros. The environmental and social data sheet dated July 15, 2026, documents how negligently the risks of the climate crisis were addressed in the project’s assessment. In light of the pending disaster, the following passage proves especially tone-deaf: „Climate risk screening concluded that physical climate risks are manageable and adequately addressed through design and operational measures. No significant climate resilience constraints have been identified.”
Switzerland
The hot summer had a direct impact on the Beznau NPP, the oldest operating nuclear power plant in the world which lacks a cooling tower. It can only be cooled using the Aare River. As a result, the reactors had to be shut down repeatedly in June, July, and August.
Nuclear Power Is Not Suited for Extreme Heat
The heatwave of summer 2026 starkly exposed nuclear energy infrastructure’s severe vulnerability. Due to their design, nuclear power plants depend on a steady supply of water and specific temperatures for cooling and discharge. This is one of the many reasons why nuclear power generation cannot guarantee energy stability in the face of global warming.
Notes
- www.srf.ch/news/dialog/energieversorgung-im-sommer-die-abhängigkeit-vom-wasser-ist-ein-problem-fuer-atomkraftwerke
- https://www.euronews.com/2026/09/01/heatwaves-and-secret-emissions-why-nuclear-power-may-not-be-as-green-as-you-think „The Nuclear Energy Institute, one nuclear reactor requires between 1,514 and 2,725 litres of water per MWh – equating to hundreds of gigalitres every year.“
- Süddeutsche Zeitung: Raus aus der Hitzefalle, 14.08.2026
- Süddeutsche Zeitung: Das Klimadilemma der Marine Le Pen, 24.08.2026
- https://www.spiegel.de/panorama/frankreich-200-tonnen-quallen-legen-atomkraftwerk-gravelines-lahm-a-b50739cf-c317-4a24-9048-f91817a588f8
- https://wenewsenglish.com/hungary-pm-announces-closure-of-nuclear-plant-due-to-heatwave/
- https://de.euronews.com/my-europe/2026/08/27/atomkraftwerk-paks-ungarn-niedrigwasser-donau
- https://autark.news/wirtschaft/news/ungarn-akw-paks-abschaltung-strompreise
- https://finanz-echo.de/rumaenien-schaltet-akw-cernavoda-wegen-niedrigwasser-ab/
- https://www.eib.org/attachments/registers/259962479.pdf
https://www.tagesanzeiger.ch/hitze-axpo-schaltet-reaktor-von-akw-beznau-ab-835722108394
