Optimized dispatch and component sizing for a nuclear-multi-effect distillation integrated energy system using thermal energy storage

Abstract

For nuclear power plants to remain competitive in energy markets increasingly penetrated by variable renewable energy sources, designs that allow flexible operation or incorporate additional revenue streams should be considered. This study models a nuclear reactor decoupled from a supercritical steam Rankine cycle through a two-tank thermal storage system using molten salt as the heat transfer fluid. The model allows steam extraction from the power cycle’s low-pressure turbine to provide thermal energy to a thermal desalination facility. The desalination facility likewise includes a two-tank thermal storage system. This study aims to determine the conditions under which thermal storage integrated with nuclear-desalination systems increases economic competitiveness compared to standalone nuclear power plants. We built a mixed-integer linear program that determines optimal dispatch schedules and subsystem sizing of the energy storage components given current price parameters in the literature. We then performed sensitivity analyses to turbine size, thermal storage system cost, and desalinated water price. We found that multi-effect distillation increased the revenue generation of the system beyond standalone conditions except when the price of desalinated water decreased beyond 30% of its nominal 2021 price. We also found that when the turbine is oversized, high-temperature and low-temperature thermal storage is dispatched in a complementary fashion that allows for load-following and continuous distillate production.