Finland’s Steady Energy, a startup company spun out from the VTT Technical Research Centre of Finland in 2023 and Swedish project developer Kärnfull Next have announced a strategic partnership to introduce small modular reactors (SMRs) for district heating in Sweden. Steady Energy is already set to build SMRs in Helsinki and Kuopio, Finland, targeting the first commercial unit for operation by 2030.

The collaboration leverages Kärnfull’s innovative financing structures and delivery models to bring Steady Energy’s district heating reactors to Sweden. Steady Energy is seeking to construct a heating plant in Finland based on its LDR-50 reactor technology. The LDR-50 district heating SMR has been under development at VTT since 2020. It is designed to operate at around 150°C and below 10 bar (145 psi).

The LDR-50 reactor module comprises two nested pressure vessels, with their intermediate space partially filled with water. When heat removal through the primary heat exchangers is compromised, water in the intermediate space begins to boil, forming an efficient passive heat transfer route into the reactor pool. The system does not rely on electricity or any mechanical moving parts, which could fail and prevent the cooling function. The innovation was awarded a patent in 2021.

“With Steady’s reactor in our portfolio, we complement our electricity-focused ReFirmSouth SMR programme with a new bespoke district heating offer for municipalities in need of sustainable heating solutions”, said Kärnfull Next CEO Christian Sjölander.

Steady Energy has previously signed letters of intent for the delivery of up to 15 reactors with Helsinki’s local utility Helen and Kuopio Energy in Eastern Finland. The construction of the first commercial plant is projected to begin in 2028, with the first unit anticipated to be operational by 2030. Construction of the first SMR pilot plant in Finland is expected to begin next year with candidate sites in Helsinki, Kuopio and Lahti.

Tommi Nyman, CEO of Steady Energy, noted: “Sweden’s electricity consumption is projected to increase significantly to meet net-zero targets, driven by the electrification of transport and industry. This necessitates corresponding clean heating energy to maintain Sweden’s carbon commitments.”

Sweden’s district heating consumption amounts to approximately 50 terawatt-hours (TWh) a year, two-thirds of which comes from biomass, with fuel costs rising sharply in recent years. Generally, the future of biomass within district heating is being questioned, not least since it is seen to have more valuable alternative uses. Additionally, the combustion of biomass leads to the emission of biogenic greenhouse gases.

“Heating a large city with biomass requires a pile of logs the size of a football field every single day, with a constant stream of trucks around the clock. It’s high time that our societies limit burning wood to heat our homes. By combining our expertise, Steady Energy and Kärnfull Next are poised to bring SMR district heating to Sweden, speeding up ambitious climate and sustainability goals”, said Nyman.