Effect of investment cost on technology preference in a flexible, low-carbon Finnish power system

This paper investigates the effects of varying investment costs in a cost-optimal portfolio of electricitygenerating technologies to achieve a low-carbon power system to help mitigate climate emissions in Finland. Several different cost scenarios for nuclear, solar, wind, and battery technologies are constructed, considering both single- and multi-stage investment-strategy pathways, with sector coupling of the power system to the heating sector and hydrogen production. Potential new nuclear investments are assumed small modular reactors capable of flexible operation, and optional additional flexibility measures from heating and hydrogen sectors are considered. The scenarios are simulated with hourly resolution using GenX, an openly available capacity expansion optimization tool. Across a wide range of assumed investment costs, the results demonstrate a clear role for flexible nuclear power as a provider of both a solid base generation and flexibility to enhance integration of intermittent wind to the system. Despite optimistic cost assumptions for solar and batteries, their role is observed to remain marginal in the Finnish setting, likely due to large seasonal variation in the local solar availability.