Drought restricts European nuclear power plants. Poland plans to cool reactors with Baltic Sea water

Low water levels in European rivers have disrupted the operation of nuclear power plants in Romania, France and Hungary in recent weeks. Poland’s project being developed in Lubiatowo-Kopalino may avoid such problems thanks to the use of an open cooling system supplied with water from the Baltic Sea. How could this solution affect the natural environment?

Nuclear power plant on a river? Not during droughts and heat waves

We have written more than once in Wodne Sprawy about the inseparable relationship between water and energy. The exceptionally warm and dry summer of 2026 has reminded us of this interdependence with particular intensity: due to low water levels in the Danube, Romania’s Cernavodă nuclear power plant temporarily shut down both reactors, while Paks in Hungary and French power plants along the Seine, Rhône and Garonne experienced significant power reductions.

The problem is not only the limited availability of water for reactor cooling, but also environmental requirements setting the maximum permissible temperature of water discharged into rivers. As increasingly shallow rivers warm up, using their water for cooling is not only less efficient but also poses a threat to the natural environment. Many species of fish, amphibians and invertebrates cannot survive elevated water temperatures, which can lead to mass mortality.

Lubiatowo-Kopalino, a convenient location on the Baltic Sea

On July 17, 2026, the Polish Parliament passed an amendment to the Water Law, which will enter into force at the beginning of next year. Under the new regulations, recovered water from treated municipal wastewater may be used to cool power plants and combined heat and power plants. This is an important step toward a circular economy, aimed at reducing pressure on rivers, especially during periods of drought and heat.

Lawmakers expect the amendment to allow some combined heat and power plants to reduce their water intake from rivers by as much as several dozen percent. However, this does not guarantee a solution to all problems.

Poland’s first nuclear power plant in Lubiatowo-Kopalino, whose construction is scheduled for completion in 2038, will significantly increase pressure on water resources. Large reactor units require tens of cubic meters of water per second for cooling. Polskie Elektrownie Jądrowe (PEJ) have opted for an open cooling system that will use seawater, available in practically unlimited quantities.

PEJ explains that water will be drawn from a depth of 24 m, at a location more than 5 km from the shore, while the discharge point for used water will be located approximately 4 km from the beach, at a similar depth. The channels are to be laid beneath the seabed, with only the structures forming their endpoints extending above it.

Worth knowing: Nuclear power plants also use closed cooling systems, which do not involve discharging water into the environment. Water intake is then significantly lower, but it requires monitoring and replenishment because some of the water evaporates. Examples of such nuclear power plants can be found in the Czech Republic (Temelín, Dukovany) and Slovakia (Mochovce, Bohunice).

Can warm water from the power plant harm Baltic ecosystems?

Water discharged from nuclear power plants is usually several to a dozen degrees warmer than the water taken in. This raises questions about the risks associated with local warming of the Baltic Sea and the impact of this change on nearby ecosystems. In the sea, this risk is naturally lower than in a river, but it cannot be ignored.

According to PEJ representatives, the Lubiatowo-Kopalino plant will be equipped with a diffuser system to facilitate water mixing, so that at the discharge point the temperature measured at the sea surface will not be more than 2°C higher than the surrounding water. The 2022 environmental impact report does not identify any negative impact of the planned investment on the Natura 2000 site Coastal Baltic Waters.

The long-term consequences of the open cooling system, including its impact on changes in Baltic Sea temperature, storms, ice formation and sea levels, will only become apparent over the course of decades. However, there is no doubt that locating Poland’s first nuclear power plant on the coast reduces the risks associated with recurring droughts and heat waves.