Hungary’s Paks nuclear power station, which provides nearly half of the country’s electricity, will be fully shut down in the coming days for the first time in its 44-year history because the Danube has fallen too low to cool its reactors. Prime Minister Péter Magyar warned that the closure, expected by Monday or Tuesday, could trigger an energy crisis and called on large industrial consumers to cut electricity use voluntarily.

The shutdown is the most acute consequence of a prolonged drought and series of heatwaves that have pushed water levels on Europe’s major commercial waterways to record lows. On the Rhine, Germany’s busiest freight artery, the gauge at Kaub briefly touched the previous all-time low set in 2018, while at Düsseldorf the level was forecast to fall to 21 centimetres on Saturday, two centimetres below the 2018 record. Further downstream at Lobith, on the Dutch border, authorities registered the lowest level since measurements began.

The low water is forcing barges to reduce loads or cease operations, shifting goods onto road and rail. The German construction federation warned that the Rhine is being “pushed to the limit of its capacity” and called for urgent investment to make waterways more resilient to climate change. Scientists attribute the extreme conditions to human-caused climate change, which is making such heatwaves more frequent and intense.

In Hungary, the Paks plant’s four Russian-built reactors are already running at less than half their combined 2-gigawatt capacity. The operator said the volume of water in the Danube remains sufficient for cooling, but the river level has dropped below the intake pumps, making it impossible to draw enough water. Emergency pumps are being deployed, and the plant insists that even a prolonged shutdown can be managed safely. The government has ordered decorative lighting on public buildings to be switched off and asked parliament to postpone sessions to save energy. Neighbouring Romania has also shut one nuclear reactor because of low river levels.

Hydrological forecasts offer little relief. German authorities expect Rhine levels to keep falling in the coming week, and the Hungarian prime minister said the Paks plant may remain offline for several weeks until the Danube recovers. The European Commission said it is monitoring the situation but sees no immediate threat to supply security, while standing ready to convene an emergency coordination meeting if needed.