As the Danube hits record lows and Budapest scrambles to keep the lights on, Hungary’s energy crisis is a warning shot for every nation that let ideology override infrastructure.

For 44 years, the Paks Nuclear Power Plant never went dark. This weekend, it did — and the reason says as much about decades of European energy planning as it does about the weather.

Record-low water levels on the Danube River have left Paks unable to draw enough water to cool its reactors, forcing Hungarian Prime Minister Péter Magyar to power down the plant that supplies nearly half the country’s electricity. It’s the first full shutdown in the facility’s history, and it’s happening at the worst possible time — in the middle of a punishing regional heat wave, when demand for power is at its peak.

A River Running Dry, A Grid Running Out of Options

The numbers tell the story. Paks normally produces around 2,000 megawatts. By Friday, output had fallen to under 1,000. By Saturday night, it had dropped below 250 before the plant went fully offline. The Danube’s level near the plant has fallen well past the previous record set in 2018, and forecasters say there’s no meaningful rain in sight to reverse it.

Budapest isn’t alone. Romania shut down both reactors at its Cernavodă nuclear plant in late July for the same reason. Serbia’s largest hydroelectric station is running at a fraction of normal capacity. Commercial barge traffic on the Danube has ground to a halt in stretches of the river too shallow to navigate, disrupting shipping lanes that Central European industry depends on.

Hungarian officials are already bracing for the financial hit. Government estimates suggest replacing the lost nuclear output with emergency electricity imports could cost the country hundreds of millions of euros before the crisis is over. In the meantime, Budapest has rolled out rationing measures that would have seemed unthinkable a decade ago in a modern European economy: industrial users being told to cut consumption during peak hours, freight rail suspended for hours each day to conserve grid capacity, and public buildings ordered to switch off decorative lighting.