Company planning up to 3,400 MW of new capacity at Oskarshamn site
Power company Fortum has submitted an application for Swedish state aid to build new nuclear reactors at Oskarshamn, southeastern Sweden, as it seeks to meet rising customer demand for energy.
The application was submitted on 27 August through Nucore Energi, which is wholly owned by Fortum and was established specifically for the planned nuclear new-build project.
The reactors would be built next to the existing Oskarshamn nuclear power station, a facility in which Fortum is a significant minority owner.
Fortum has a minority interest in the three-unit Olkiluoto nuclear station in Finland and in four units – Oskarshamn-3, Forsmark-1, Forsmark-2 and Forsmark-3 – in Sweden.
Fortum is planning a facility with capacity ranging from 1,200 MW to 3,400 MW, Nucore Energi chief executive officer Laurent Leveugle said.
There are two older units at Oskarshamn that were permanently shut down in 2016 and 2017.
Fortum has been assessing options for new nuclear power in Sweden since 2022. The application does not constitute an investment decision, but formally starts discussions with the Swedish state over potential support for the project.
If the plan goes ahead, Fortum would eventually look to be a minority holder.
Last year Fortum completed an extensive feasibility study exploring the commercial, technological, and societal prerequisites for new build in Finland and Sweden.
The study concluded that with the current power market outlook, new nuclear is not economically viable on a merchant basis only. Merchant basis refers to selling generated electricity into the wholesale market without a fixed-price contract, meaning the project’s revenue depends on volatile spot market prices, introducing significant financial risk.
Government’s Push For New Nuclear
However, based on the study and also on new build projects in other western countries, new nuclear projects can be manageable with a solid risk sharing framework when matched with increased customer demand, Fortum concluded.
The two-year feasibility study covered both small modular reactors and conventional large reactors, and involved discussions with several technology vendors, potential partners and customers, and societal stakeholders.
Fortum said that after the finalisation of the feasibility study, it continued project development, “building capabilities needed to keep new nuclear as an option to meet future customer demand in the Nordics”.
Sweden’s government has opened a new chapter for nuclear energy in the country, reversing a decades-long policy to shut down its reactors.
Sweden has six large-scale reactor units in commercial operation at three sites: Forsmark, Oskarshamn and Ringhals. According to International Atomic Energy Agency data, nuclear energy provided 29% of the country’s electricity generation in 2024.
The country now plans to add around 2.5 GW of capacity by 2035, with the aim of deploying both large-scale reactors and small modular reactors.
Sweden has designed a comprehensive support package that includes a minimum electricity price, state-backed construction loans and a mechanism for sharing project risks.
In 2025 Fortum and US-based Westinghouse Electric Company signed an early works agreement for the possible deployment of advanced AP1000 reactor technology in the Nordics.
The existing Oskarshamn nuclear power station site in Sweden. Courtesy OKG.
