Load shifting of nuclear power plants using cryogenic energy storage technology

•Cryogenic energy storage is used for grid scale load shifting of nuclear power plant.•Supercritical air liquefaction and re-gasification processes are facilitated by thermal fluid based sensible cold storage.•Peak capacity of nuclear power station can be nearly tripled with a roundtrip efficiency of around 70%. To balance the demand and supply at off-peak hours, nuclear power plants often have to be down-regulated particularly when the installations exceed the base load requirements. Part-load operations not only increase the electricity cost but also impose a detrimental effect on the safety and life-time of the nuclear power plants. We propose a novel solution by integrating nuclear power generation with cryogenic energy storage (CES) technology to achieve an effective time shift of the electrical power output. CES stores excess electricity in the form of cryogen (liquid air/nitrogen) through an air liquefaction process at off-peak hours and recover the stored power by expanding the cryogen at peak hours. The combination of nuclear power generation and the CES technologies provides an efficient way to use thermal energy of nuclear power plants in the power extraction process, delivering around three times the rated electrical power of the nuclear power plant at peak hours, thus effectively shaving the peak. Simulations are carried out on the proposed process, which show that the round trip efficiency of the CES is higher than 70% due to the elevated topping temperature in the superheating process and thermal efficiency is also substantially increased.