Performance research of a liquid air energy storage system integrated with pressurized water reactor nuclear power plants

Given the challenges of peak regulation in nuclear power plants, a new liquid air energy storage system integrated with a pressurized water reactor nuclear power plant (LAES-NP) is proposed. The LAES-NP system uses excess nuclear power to prime the air compressor of the liquid air energy storage (LAES) system, while also extracting part of the main steam further to increase the temperature of the heat transfer oil, recovering waste heat between the compressor stages. The system can consume excess power from the nuclear power plant during the valley, increase its output power during the peak, and minimize load fluctuations in the primary and secondary circuits. At the same time, the round-trip efficiency of the LAES can be obviously improved. The optimal performance of the system is achieved with a mass flow of extracted main steam of 70.5 kg/s, a round-trip efficiency of 73.5 %, and an energy efficiency of 60.3 %. Under the design condition that 20 % of the rated power of the nuclear power plant is absorbed at valley time, an additional 12 % of the rated output power of the nuclear power plant can be provided at peak time. Exergy analysis results show that the exergy efficiency of the LAES is 56.2 % in system design conditions, and exergy losses mainly occur in the throttle valves, cold exchangers, and evaporators. According to the results of the economic analysis, the LAES-NP system has the best economic performance under the operation mode of the combined thermal and electrical storage. Its levelized cost of storage (LCOS) is $ 0.1557 /kWh, its net present value (NPV) is $ 407.72 million, and its dynamic payback period (DPP) is only 5.77 years. The research results of this paper can provide a new way of peak regulation in nuclear power plants.