Slovak power utility Slovenské Elektrárne (SE) is reviewing a new project to increase the energy use of the Mochovce NPP. SE says it is considering “the efficient use of the so-called waste heat from the cooling circulating water from the non-nuclear part of the power plant for a year-round heat supply for the city of Tlmač”. This would help reduce the carbon footprint of heating in the city. “The project includes the construction of a hot water pipeline and technology for heat transfer between NPP Mochovce and Tlmač.
SE will be responsible for any investment related to the territory of the NPP. Private heating company Esi Tlmač (part of the Esi group and formerly National Energy) will take care of investments in technology from the connection point to the Lipník estate, six kilometres away from the power plant. Esi Tlmač has already submitted an EIA environmental impact assessment for the project to the licensing authorities. The company will also replace the existing biomass and gas boilers with new water/water heat pumps. The aim is to install an optical network for data transmission at the same time as the pipeline.
The technical solution of the project envisages the connection to the cooling circulating water discharge pipes and the construction of an exchange station. The water taken from Hron and used to cool the NPP is currently returned to the river. The plan is for this circulating water with a temperature of 25-36°C to transfer its heat through the heat exchanger to a closed secondary circuit. This will be sold to Tlmač through the subsidiary Slovenské elektrárne – energetické služby.
The project is in the initial phase, the selection of the technical solution and the economic evaluation of the project are now underway. Implementation is currently planned for 2027 for completion at the beginning of 2028. The project was originally outlined by Enviroportál. “The purpose of the proposed project is the construction of a pipeline connection between the Mochovce NPP and the boiler plant on Kotlárská Street in Tlmač. Waste heat, which is obtained from the cooling water of the power plant, will be transferred to the boiler room, where it will be used in heat pumps to heat water for the central heat supply system.
While this is the first such project in the Mochovce region, since 1987, SE has been producing heat for Trnava, Leopoldov, Hlohovec and the municipality of Jaslovské Bohunice from the Jaslovské Bohunice NPP. This plant produced 429 GWh of heat in 2023. The high ten-kilometre hot water pipe between the Jaslovské Bohunice power plant and the Trnava heating plant began construction in 1983 and was put into operation at the end of 1987. While this project was state funded, the project at Mochovce will be supported by private investment.
The town of Tlmač has 3,500 inhabitants. Apartment buildings in the Lipník housing estate and also urban buildings are heated by a boiler room. “These are 1,166 housing units and 12 buildings in the city, which include, for example, an elementary and kindergarten school, a health centre, a relaxation centre with a swimming pool, a community centre, a service centre, and others,” said Zuzana Kotrus Rákociová, head of the city office. The city leased the heat management until 2032 to Esi Tlmač. More than ten years ago, the company began burning wood chips, which was more environmentally friendly than fossil fuels. However, this is proving unprofitable in the long run, Rákociová explained, which is why they are now looking to Mochovce NPP. “The plant has residual hot water that is waste and can be used as a future source in heat production.” he said.
