Abstract

In power systems with high shares of variable renewable energy sources, dispatchable generation technologies must operate flexibly, adjusting their output continuously throughout the day. This mode of operation negatively impacts the economic viability of such technologies, particularly those with high capital expenditures, such as nuclear power. However, the potential use of nuclear technologies in hydrogen co-generation has been shown to mitigate this apparent disadvantage, while also enabling a low-emission pathway for hydrogen production. This article proposes an energy planning model to assess the economic viability of nuclear generation technologies in a system with high levels of renewable generation. The model is implemented using the well-known Open Source Energy Modeling System (OSeMOSYS). This study evaluates the economic and operational impacts of installing three NuScale modular nuclear power plants, each with a capacity of 720 MWe, within the evolution of the Chilean power system between 2025 and 2060. A novel integration scheme is analyzed in which nuclear technology supplies part of the thermal energy required for high-temperature electrolysis, while electricity is sourced from the grid. Scenarios were evaluated for both electricity-only nuclear generation and nuclear-assisted hydrogen production via combined electricity and heat supply. The main results show that, although the economic competitiveness of nuclear power for electricity-only generation is limited within the context of Chile's energy transition, it can be significantly enhanced when used to support hydrogen production. The hourly operating profile of nuclear power plants is well suited to support Solid Oxide Electrolysis Cell (SOEC) technology during daytime hours - when low-cost photovoltaic electricity is abundant - and to shift toward electricity generation during nighttime hours. Across the scenarios studied, the average system unit cost of producing hydrogen ranged between $2.53/kgH2 and $3.02/kgH2. Under the most favorable CAPEX assumptions for both nuclear and SOEC technologies, systemic hydrogen production costs could be reduced by up to 14% compared to scenarios based on low-temperature electrolysis.