Hungary may lose 40% of its electricity as nuclear plant shuts

Signals Inbox·August 2, 2026·Nuclear

Hungary’s only nuclear plant is falling from roughly 2,000 megawatts to zero because the Danube is too low to cool it safely. Paks normally supplies around one-third to 40% of the country’s electricity, so a dry river is suddenly removing Hungary’s biggest source of steady power.

Q1What actually happened?

Hungarian Prime Minister Péter Magyar said in the official announcement that another Paks reactor would stop, cutting the plant to just 240 megawatts before a complete shutdown. Paks normally produces around 2,000 megawatts across four reactors. That means roughly 88% of its capacity had already disappeared before the final unit went offline.

Q2Why can a low river stop a nuclear plant?

Nuclear reactors create huge amounts of heat, and Paks uses Danube water to cool its equipment. The river became so low that its pumps could no longer take in enough water reliably. The reactors can be shut down safely, but they cannot keep producing electricity without a stable cooling supply.

Q3Is Hungary really losing 40% of its electricity?

Paks produces around one-third to 40% of Hungary’s electricity over a typical year, with some official and media estimates putting its share closer to half during certain periods. That does not mean 40% of homes instantly go dark. Hungary can increase imports, run other plants, use solar during daylight, and ask large consumers to reduce demand. But replacing up to 2,000 megawatts at short notice is still a massive grid problem.

Q4Why is the timing especially bad?

The shutdown is happening during extreme heat, when air conditioners push electricity demand higher. Hungary has built a lot of solar, which can cover a large part of daytime use. The harder period comes between late afternoon and night, when solar output falls but homes and businesses still need power. That is when Hungary becomes more dependent on gas plants, industrial cuts, and electricity imported from neighboring countries.

Q5Has Paks ever completely stopped before?

Not like this. Its four reactors entered service between 1982 and 1987, and this is the first full plant shutdown in roughly 44 years of operation. Individual reactors have stopped for maintenance or technical problems before. The unusual part is that every reactor is being taken offline because the river itself can no longer support normal operation.

Q6Does this prove nuclear power is unreliable?

Not by itself. Nuclear plants usually run far more consistently than wind or solar. But this exposes a specific weakness: many large reactors depend on rivers, lakes, or the sea for cooling. France has previously reduced nuclear output when rivers became too warm, and Romania has also faced Danube-related reactor interruptions. Climate stress can therefore hit nuclear power through both water temperature and water availability.

Q7What is the bigger signal?

Hungary did not lose power because a reactor failed. It lost power because the natural system around the reactor failed. That changes the energy-security conversation. Countries need backup generation, stronger cross-border connections, storage, and cooling systems designed for more extreme weather. Paks may restart when the Danube rises, but the assumption that steady nuclear power is completely separate from weather just took a serious hit.