Steady Energy designs, constructs and plans to operate compact, low-temperature nuclear heating plants based on its LDR-50 small modular reactor. The reactor is a heat-only design running at low temperatures and pressures, rated at about 50 MW thermal and sized roughly like a shipping container, with a built-underground layout, light water technology and refuelling every 2 to 3 years. The company says its target levelised cost of heat is under EUR 40/MWh and that its lifetime carbon footprint is similar to offshore wind.

The technology originated at VTT, the Technical Research Centre of Finland, where researchers began work on a simplified reactor for low-temperature heat in 2020. Steady Energy was spun off in 2023 and is positioned as a complement to renewables, supplying carbon-free heat to district heating networks during cold, low-sun periods. Its customers and partners include Finnish utilities Helen and Kuopion Energia, which have signed agreements or expressed interest, and it has preliminary agreements for up to 15 reactors in Finland. It has also expanded into Sweden and Poland and signed a cooperation agreement with Korea District Heating Corp.

The company is building a pilot plant in central Helsinki, with a stated plan for a decision on its first commercial plant in 2028 and first commercial operation in the 2030s. Its regulator STUK published a summary of an international Joint Early Review of the LDR-50 design in July 2026 that identified no fundamental issues preventing the concept from being further developed. In September 2026 the company agreed to combine with the investment company 3North Partners and list on Nasdaq First North Growth Market Finland, and the EIB provided up to EUR 40M in convertible financing, its first SMR financing.