Feasibility of small modular reactors for decarbonizing district heating systems: a case study of the Helsinki metropolitan area

This study explores the feasibility of integrating small modular reactors (SMRs) into the district heating (DH) and cooling system of the Helsinki metropolitan area, Finland. The objectives of the study are to evaluate the economic and operational aspects of two SMR technologies, the academic concept E-SMR (155 MWelectric/50 MW_DH) and the VTT-developed LDR-50 (50 MW_DH), as well as their environmental impact on the DH and cooling system using the Backbone modeling framework. Despite investments in biomass-fired DH generation and large heat pumps, Helsinki remains heavily dependent on fossil fuels. SMRs could potentially offer a reliable and continuous supply of carbon-free energy. Results indicate that while both SMR designs reduce CO2 emissions and enhance electricity supply, E-SMR is not a profitable investment, whereas LDR-50 is. The fluctuating energy demand and low electricity prices in the studied area presented challenges for the larger E-SMR. Heat production capabilities are highly valued in the studied system, which was reflected in LDR-50′s profitability and the sensitivity study of E-SMR's heat extraction rate. Sensitivity analyses highlighted the influence of economic factors such as investment costs, discount rates, and operating expenses on the profitability of both SMRs. Additionally, energy market conditions play a crucial role in determining the financial viability of SMRs, suggesting that their profitability can vary significantly under different market scenarios. Integrating SMRs into future energy systems, such as electrolyzers, could enhance their feasibility, warranting further research. Moreover, the economic viability of different fuel strategies should be investigated to explore their potential benefits for SMRs.