Economic competitiveness of a nuclear-renewable hybrid energy system with water desalination: case of study

Nuclear-renewable hybrid systems could be an option for electricity systems composed of 100 % clean sources (non-GHG emitting sources). The proposed hybrid systems in the literature show reactors working at 100 % capacity where associated industrial processes and energy storage units are using energy not required for electricity generation. The current case study proposes a 100 % hybrid energy system composed of renewable variable sources (wind and photovoltaic), small modular reactors, and an associated reverse osmosis desalination process, where the reactors will work in a load-following electricity demand mode. An actual isolated electricity system in Mexico composed of aging fossil fuels, wind, and photovoltaic power plants comprises the proposed case study. This region is suffering from water stress. The aging fossil plants are replaced with small modular reactors with an associated reverse osmosis plant system to alleviate water scarcity. The case study considers actual changes in electricity demand on the region's seasonal and daily basis. Results are promissory, having a variable renewable installed capacity penetration of 22.48 %; the hybrid system can follow electricity demand. The proposed hybrid system is economically competitive for investment discount rates up to 7 %, assuming an electricity selling price of 100 US$/MWh and a potable water price, in the region, of 1.70 US$/m3. The study shows that the load-following procedure, in the worst-case scenario, does not compromise the lifetime of nuclear components and ensures normal nuclear operation conditions in the whole fleet of small modular reactors. The results obtained set some guidance conditions for these types of hybrid systems.