The week the Danube ran out

The Number on the Gauge

At 16:00 on Sunday 2 August 2026, the Hungarian water authority's gauge on the Danube at Paks read minus 134 centimetres. That number, one metre and thirty-four centimetres below the gauge's zero point, is written into the operating rules of the four-reactor plant a few hundred metres from the riverbank: at minus 134, the last unit of the Paks Nuclear Power Plant, the machine that generates half of Hungary's domestic electricity, must power down. By the time the reading printed, the plant had already all but complied. ENTSO-E actuals show output settling at 166 MW at three o'clock that morning, less than a tenth of the 1,850 MW the same four units had delivered the previous Monday.

Nothing was broken. No turbine tripped, no cable burned, no storm hit. The fuel was loaded, the operators were at their desks, and the machines were in perfect working order. What failed was the river. The Danube at Paks had been falling all summer, past the minus 98 centimetre record set in 2018, past every level in the plant's 44-year operating history, until the fixed intake pumps that drink its cooling water began to run out of water to drink. Hungary's prime minister announced the first complete shutdown the plant had ever faced and warned of a possible energy crisis within days. Forecasts said the river might reach minus 144. It stopped at minus 140, on Tuesday 4 August, and by then the plant was a 170 MW shadow, the government had taken powers to disconnect industrial consumers, freight trains were being held out of the evening peak, and the Hungarian zone's 19:00 price had just cleared at 418.9 €/MWh.

This editorial walks the fortnight hour by hour: the seven-step staircase down, the second nuclear plant the same river took offline a thousand kilometres downstream, the border-by-border scramble for imports, and the two-speed price map it left across Central and Eastern Europe. The narrator throughout is the data.