Hungary’s NPP Paks has begun restoring electricity production following a period of reduced output during last week’s heatwave. The change comes as cooler weather eases cooling constraints tied to high Danube water temperatures. The plant is increasing generation levels while staying within environmental operating limits.
Heatwave-driven output reduction and cooling-water limits
During the extreme heat, Paks reduced output gradually in coordination with Hungary’s electricity transmission system operator MAVIR. The adjustments were made to comply with rules governing the temperature of cooling water discharged into the Danube. The nuclear facility, with an installed capacity of 2,000 MW, uses river water to cool its reactors before returning it downstream.
Hungarian regulations require discharged cooling water to remain below 30°C within 500 metres of the outlet point. Under exceptional circumstances, the limit can be temporarily raised to 31.5°C if the energy minister determines that the measure is necessary to protect security of electricity supply.
System monitoring during the heatwave
The Hungarian government said earlier that the electricity system remained stable throughout the heatwave. It also reported that continuous monitoring found no indication that higher river temperatures posed a threat to the Danube ecosystem. On that basis, the temporary reduction at Paks was handled as a precautionary operational step rather than a broader system-security issue.
Gradual restart as temperatures decline
As temperatures have started to fall, Paks has begun gradually increasing generation levels. Forecasts call for more moderate conditions in the coming days, with daytime temperatures expected around 30°C. The outlook also includes periods of rain and thunderstorms intended to further improve cooling conditions.
The return of Paks output is expected to add stability to Hungary’s electricity system. It would reduce pressure on imports and support supply availability while regional power markets face volatility during periods of high demand and weather-related constraints.
