Drought shuts European nuclear plants as Danube, Rhine and Po hit record lows

Drought chokes Europe's major rivers

Europe's fifth heat wave of the season has pushed the Danube, Rhine, and Po to record-low levels, disrupting freight transport, industrial production, and power generation across the continent. The Danube fell to just 23 centimetres at Budapest, while the Rhine is shallower than at any point since records began and the Po hit a historic summer low in Italy. River transport of chemicals, petroleum products, and other goods on the Rhine and Danube has been nearly halted in certain sectors. Several thermal and nuclear power plants have had to reduce output because of cooling water shortages or elevated river temperatures. In Serbia, Germany, and Bulgaria, the drought has exposed shipwrecks and prehistoric relics on newly visible riverbeds.

Nuclear plants pushed to the brink

The drought has exposed the dependence of nuclear power on river water for reactor cooling. In Hungary, the Paks nuclear plant, with an approximate capacity of 2 gigawatts and supplying more than a third of the country's electricity in a normal year, has been reduced to roughly 25% of capacity. Authorities have mobilised engineers to move about 145,000 cubic metres of rock into the Danube riverbed to slow the current and conserve water upstream. The Hungarian government announced on Wednesday that it will build a threshold structure across the riverbed, a project expected to take several weeks. On Saturday morning, Hungary began sinking two 80-metre barges to raise the water level; Prime Minister Péter Magyar said the level at the plant had risen by 1 centimetre.

In Romania, operator Nuclearelectrica shut down the second reactor at Cernavodă as the Danube continued to drop, taking both 700 MW units offline and removing 1,400 MW of capacity from the grid. Cernavodă normally supplies about 20% of Romania's controllable electricity production. The Romanian Navy detonated approximately 180 kilograms of explosives earlier in the month in an operation to redirect Danube water toward the plant's cooling systems. Bulgaria has become an increasingly important electricity supplier for Romania, which holds about 4,000 MW of cross-border interconnection capacity. The Romanian Energy Ministry has indicated wind parks, the Rovinari 4 plant, and hydroelectric facilities as sources able to cover part of the deficit.

Economic damage and an insurance gap

According to Moody's data, heat waves in previous years cost the European economy approximately €43 billion in GDP losses, yet insurance covered only about €500 million of that damage. A survey by the European insurance regulator found that just 28% of small and medium enterprises hold business interruption insurance, and only 17% have policies covering operational stoppages without physical damage. Parametric insurance, which triggers automatic payouts when temperatures exceed a preset threshold, is a growing alternative; that market is estimated to approach $8 billion by 2031. The fifth heat wave has hit sectors including hospitality, retail, agriculture, and transport through indirect losses such as reduced labour productivity, higher air-conditioning costs, rail delays, and equipment failures.

Riverbeds yield historical relics

As water levels drop, long-submerged artefacts have surfaced. Near Prahovo in Serbia, Nazi ships sunk in 1944 now sit broken on sandbanks. In Croatia, a cargo vessel from the 1930s has partially emerged from the water. In Bulgaria, local experts have discovered what may be the scattered remains of a prehistoric mammoth skeleton on the exposed Danube bed.