Economic feasibility assessment of a solar aided liquid air energy storage system with different operation strategies

Abstract

In response to severe environmental problems, the proportion of new energy consumption worldwide is on an unprecedented upward trend, bringing energy storage technologies into focus. Among various energy storage systems, the solar aided liquid air energy storage (SALAES) system shows great prospects for development due to its cleanliness and high efficiency. This paper develops a basic operation strategy based on the idea of peak and valley reduction, considering the temporal fluctuation characteristics of solar energy. Further, operation modes for replacing the oil-air heat exchangers are proposed and an optimized strategy is developed accordingly. Real weather data of Beijing are used to estimate the annual power output of each system, and economic analyses are carried out on this basis using the levelized cost of storage (LCOS) method. The results show that the introduction of solar energy can reduce the LCOS of the liquid air energy storage system by 4.1 %–13.67 % and the proposed optimized operation strategy can increase the annual power output, resulting in a 0.2 %–0.4 % reduction in LCOS compared to the basic operation strategy. In addition, the impact of the molten salt tank capacity on the investment and return of the SALAES system is investigated. The optimal molten salt tank capacity obtained in this paper is 5 h, with the lowest LCOS of 0.1477 $/kWh and the shortest dynamic payback period of 10.29 years when operating with the optimized strategy.