Optimization and performance evaluation for liquid air energy storage based on liquid natural gas cold energy utilization
Liquid air energy storage(LAES)is a promising technology for large-scale energy storage due to its geographical flexibility and high energy storage density.To further improve the round-trip efficiency and economic benefits of LAES,a novel integrated system combining liquid natural gas(LNG)cold energy utilization and organic Rankine cycle(ORC)with LAES is proposed.Thermodynamic and economic analysis methods for the integrated system are established,and the effects of key parameters on the system's thermal performance are investigated based on simulations.An economic analysis of the system is also conducted.The results show that,as the system's expansion pressure increases,both efficiency and power output rise,but at a decreasing rate.The system's round-trip efficiency increases with more expansion stages up to a point,then decreases.With four-stage expansion,the system efficiency reaches 62.26%,which is 7%～12%higher than that of the conventional LAES system.When the difference between peak and valley electricity prices is 0.848 yuan/(kW·h),the net present value,dynamic payback period,and levelized cost of electricity are 119058500 yuan,4.48 years,and 0.893 yuan/(kW·h),respectively.The results of this study can provide a reference for engineering application and efficiency improvement of LAES systems.
liquid air energy storageLNG cold energy utilizationorganic Rankine cycle
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