Hungary's Paks nuclear plant at 10% capacity as Danube drought threatens European power grids

Paks on the brink

Hungary's Paks nuclear plant, which supplies close to half of the country's electricity, is running at roughly 10 percent of its 2,000 MW capacity after a cascade of power cuts forced by the shrinking Danube. Block 1 was reduced by 254 MW on the evening of 27 July, block 3 by 237 MW the following day and then temporarily shut down on 29 July, and block 2 was halved on 30 July, leaving it as the sole operating unit. Prime Minister Peter Magyar warned that a complete shutdown could last more than a month, a first in the plant's 44-year history.

“Full nuclear safety guarantee is a basic requirement, on which there is no room for compromise and which will always remain the most important.”

The Danube's level is at a record low, and with another intense heatwave forecast, further drops are expected. Magyar said the plant might be able to continue at reduced output until Monday or Tuesday, buying time during peak demand days.

Regional cascade

The crisis is not confined to Hungary. Serbia's Djerdap I and Djerdap II hydropower plants, which together account for about 18 percent of the country's annual electricity, are operating at 20 and 30 percent of capacity respectively, their lowest since coming online 23 years ago. In Romania, one of the two units at the Cernavodă nuclear plant was disconnected from the grid five days ago, temporarily removing 650 MW net and forcing the country to cover the shortfall with imports; the last such shutdown occurred in August 2003. Bulgaria's sole nuclear station, Kozloduy, is still running but authorities have asked Serbia and Romania for assistance. Croatia, which relies on hydropower for over half its electricity, is also feeling the strain, and the Krško nuclear plant it shares with Slovenia is threatened by low flow and high temperatures on the Sava River.

“The situation is serious, and the consequences could be more severe than during the 2025 blackout in Spain.”

Conservation and grid response

Facing the risk of a total blackout, the Hungarian government has appealed for voluntary energy savings, particularly between 17:00 and 22:00. On Sunday, households, businesses, municipalities and institutions together saved 700 MW, equivalent to one and a half Paks blocks, and around 300 companies pledged to cut consumption on Monday. Ilona Gizińska of the Centre for Eastern Studies noted that the country is also maximising renewable output and increasing imports, but added that the system is balancing on the edge of demand.

“We are balancing on the edge of demand.”

In Poland, grid operator PSE confirmed that high temperatures and low river levels are forcing output restrictions at some conventional plants. The Kozienice power station, owned by Enea, is unofficially reported to be among those affected, though the company has not confirmed it. PSE stated that it has operational procedures and tools to maintain stability, but did not rule out declaring a capacity market call period if reserves tighten.

What comes next

Forecasts for Tuesday 4 August show temperatures reaching 35 to 36 degrees Celsius in southern Poland, and the heat is expected to persist across the region. Mariusz Marszałkowski, an energy and security analyst, described the Paks situation as an extremely rare case, while stressing that the process of shutting down and restarting a nuclear plant is safe. With the Danube still falling, the plant's limited operation could stretch for weeks, and the broader regional grid remains under severe stress.