Slovenia’s state-owned energy company, GEN Energija, has presented key findings from two critical professional studies advancing the development of the Krško II NPP (JEK2) project. These related to transport routes and cooling tower technology.
The JEK2 project is for a plant with up to 2400 MWe capacity to be located adjacent to the existing 696 MWe Krško NPP owned and operated by Nuklearna Elektrarna Krško, which is jointly owned by Croatia’s Hrvatska Elektroprivreda (HEP Group) and Slovenia’s GEN Energija. Krško, which began operation in 1983 and uses Westinghouse technology, supplies around 20% of Slovenia’s electricity needs and 16% of Croatia’s. However, Croatia is not currently involved in JEK2 and is making its own plans.
A final investment decision is expected in 2029, with construction beginning in 2033 and commercial operation in 2041. In September 2025, GEN Energija published two technical feasibility studies for the EPR and AP1000 reactors with respect to the JEK2 project. The JEK2 project team had originally been in discussions with potential nuclear power plant providers EDF, Korea Hydro & Nuclear Power (KHNP) and Westinghouse. However, KHNP withdrew from the process in January 2025 following a dispute with Westinghouse and feasibility studies were then requested from Westinghouse and EDF.
The recent preliminary transport study evaluated eight potential routes for moving heavy, large-scale structural reactor components. The 274-kilometre-long Koper-Ljubljana-Celje-Krško route was identified as the most suitable. The plan focuses primarily on off-motorway road transport to effectively handle oversized logistics without heavily disrupting the main highway arteries.
The engineering feasibility study on cooling tower technologies analysed four distinct cooling options to minimise environmental heat loading on the nearby Sava River. The study recommends constructing a massive natural draft cooling tower (hyperbolic structure using natural air ventilation/convection). The proposed tower will stand between 193 metres and 198 metres tall. This layout represents the most environmentally friendly option because it operates with the lowest carbon footprint and protects the river ecosystem by heavily reducing the thermal discharge into the water.
Introducing the findings at a public meeting in the Krško Cultural Centre, GEN Energija Director General Andrej Vizjak noted: “Ever since I took over the leadership of GEN Energija, one of my key priorities at JEK2 is very clear: professional bases must be solid and important information presented to the public in a timely and understandable manner. In the project of this size, it is expected that there are different opinions as well as demanding issues. That is why we need an open debate based on data and arguments.”
Dr Aleš Jamšek, a water engineer in the Engineering Service, presenting the transport study, noted that it was a preliminary study representing the starting point for the preparation of the final transport study. This will address more detailed technical planning of the route, setting potential infrastructure adjustments and further preparation of transport in the subsequent stages of the project. According to the timeline, the final transport study could be completed by the end of 2028.
Dr Bruno Glaser, GEN Energija Technical Director, presented the results of the cooling tower study. He said the advantages of the recommended solution is that it does not need fans to create air flow, so electricity consumption is the lowest among the technologies in review, and requires less demanding maintenance. However, as an appropriate alternative, a solution with combined natural and mechanical traction was outlined, which would require two towers of approximately 75-80 metres high, but would have higher operating costs. The final solution will be the subject of further technical checks, and the optimal solution will be chosen, which will also be socially acceptable.
Jan Lokar, a leading engineer at the Engineering Service, presented an explanation of the differences between constant and current prices of the JEK2 project. He explained that different estimates of construction costs can only be directly compared if they are based on the same power of the plant, the same cost volume, the same base year and the same financing assumptions. Hie report showed how much funding will needed until construction in 2040 taking into account inflation.
For a power unit of 1,100 MWe, the total value of investment costs and financing costs increases from €11.819bn ($13.56bn) in constant prices to €14.838bn in current prices, taking into account inflation. However, for a power unit of 1,650 MWe, the total value of €17.466bn at constant prices increases to €21.759bnb in current prices. The difference between the amounts takes into account an increase in the expertise of material, labour costs, financing costs and other costs as a result of inflation during construction.
The overall status of the project was presented by Dr Glaser, who said: “The JEK2 project is advancing in several parallel areas, from the preparation of professional bases for siting to the production of key analyses and studies in the preparation of the tender documentation for the selection of the JEK2 supplier.”
