Hungary’s 2,000 MW Paks nuclear power plant could be forced to halt electricity generation after record-low Danube levels threatened the operation of its cooling-water intake system. The plant normally supplies about half of Hungary’s electricity and is described as the core of the country’s baseload generation. A complete shutdown would create an immediate need for higher imports and thermal replacement during elevated summer demand.
Cooling-water intake access under record-low Danube levels
Operators say the Danube still contains sufficient water for cooling, but the river is approaching a level at which the intake pumps may no longer be able to draw water into the plant. To preserve access, intake structures have been lowered. The situation is linked to conditions that are not limited to typical seasonal swings.
Water levels are reportedly 28 centimetres below the previous record low measured in 2018. They are also more than one metre below the minimum level used when the plant was designed more than four decades ago. The scale of the deviation is described as indicating a structural operating risk.
Causes cited for declining river levels
The plant attributes the decline to long-term riverbed erosion, upstream sediment retention, and historical dredging. It also points to increasingly frequent climate extremes. The absence of significant spring flooding in 2026 left the river unusually low before the summer demand period began.
Paks uses four alert levels for low-water conditions. It is currently operating under Level 3, while Level 4 requires all reactors to shut down. Management indicated that reaching Level 4 could take 24 to 72 hours, depending on river conditions.
Cooling demand changes and safety during shutdown risk
A reactor shutdown would sharply reduce cooling-water demand. Normal generation requires approximately 100 cubic metres per second, while maintaining safe cooling after shutdown needs around 5 cubic metres per minute. The operator stressed that reactor safety can be maintained for an extended period even if low-water conditions persist.
Regional power market impacts and forward price signals
Market effects are described as more immediate as reduced Paks output has already pushed Hungary toward heavier imports from Austria, Slovakia and Romania. If a full shutdown occurs, cross-border capacity would be redirected toward Hungary’s deficit, tightening supply in Romania, Bulgaria, Slovenia, Croatia and Serbia.
The risk has also moved into forward prices, with Hungarian week-ahead power developing an exceptional premium over Germany and Italy. The premium reflects the possibility that the nuclear constraint could persist into early August.
If Danube levels recover, the physical problem may ease within days and allow reactors to return to service. The deeper issue remains tied to an asset supplying roughly half of Hungary’s electricity operating with a cooling-water system designed for Danube conditions that no longer provide a reliable lower boundary.
