Integration Options for Nuclear Steam Cycle Using Liquid Air Energy Storage

As the portion of renewable energy increases in the electric grid, the conventional baseload power plants are demanded to undergo load-following operation. For conventional nuclear plants having played the role of baseload power, they need to consider options for daily shifting their load based on the change in supply. To provide an alternative solution to reactor side load following, which may involve regulatory and safety issues, researchers have worked on integrating grid-scale energy storage systems to conventional nuclear plants. While the load-following operation reduces the capacity factor, integration has the potential for producing more power during high demand.

Among potential energy storage technologies, liquid air energy storage (LAES) poses the advantages of no geological constraint, minimal environmental impact, and high potential for increasing storage capacity. Previous references have proposed integrated LAES layouts with conventional nuclear plants, but the assumptions made regarding the operation and design conditions are unrealistic. Hence, the research aims to suggest alternative solutions to the integration, reflecting implementable design parameters.

The research suggests layouts applied to the nuclear steam cycle, modelled closely from the Korean model APR1400. In place of isothermal compressors, the air compressors are driven using mechanical drive steam turbines to allow large power capacity. Furthermore, the layout replaces the flammable cold and hot storage fluids with the packed bed storage to avoid the fire risk nearby nuclear power station. The layouts are designed thermodynamically using an in-house code built using MATLAB and NIST REFPROP softwares, and the design parameters are further optimized using genetic algorithm.

The results show that the suggested layouts perform at comparable round-trip efficiencies under realistic design conditions. The research thus demonstrates the technical feasibility of the integration option using LAES for the conventional nuclear plant.