Techno-economic analysis of liquid air energy storage system considering the effect of geometric parameters of cold packed bed energy storage
Afshin Mashayekh, Nishith B. Desai, Fredrik Haglind
Abstract
• Techno-economic analysis of a liquid air energy storage system with a cold packed bed. • Round-trip efficiency keeps increasing with the size of the single tank. • There is an optimum value for tank diameter to reach the minimum levelized cost of storage. • A tank diameter of 6 m with an aspect ratio of 2 is the economic optimum value. Among large-scale energy storage systems, liquid air energy storage systems have garnered significant interest due to their high energy density, lack of geographical restrictions, and environmental safety. A critical component that significantly influences system performance is the cold energy storage, which captures the cold energy released during air evaporation in the discharging cycle and transfers it to the air liquefaction stage in the charging cycle. This paper aims to identify the optimal set of geometrical parameters for cold energy storage, consisting of a packed bed, that maximize the performance of the liquid air energy storage system, while minimizing the levelized cost of storage through a techno-economic analysis. The packed bed was modeled using a transient one-dimensional model, while the remaining components and the overall system were modeled using a steady-state zero-dimensional thermodynamic model. We analyzed the influence of the tank aspect ratio and diameter on the round-trip efficiency, total capital cost, and the levelized cost of storage of the liquid air energy storage system. Moreover, a sensitivity analysis of the influence of the different economic parameters was conducted. The results suggest that although the round-trip efficiency of the system increases with the size of the tanks, there is an optimum value of the tank diameter for each aspect ratio of the tank that minimizes the levelized cost of storage. The sensitivity analysis suggests that the round-trip efficiency of the system and the off-peak electricity price have the largest influence of the economic performance of the system. Furthermore, the findings underscore the importance of tailoring the tank design based on the specific operational and economic context, particularly off-peak electricity pricing. As the electricity price increases, the effect of round-trip efficiency on the levelized cost of storage becomes more pronounced, favoring the use of larger packed bed tanks. However, practical considerations such as manufacturability and installation constraints must also inform the final design. Based on our results, and manufacturing and installation constraints, we recommend an aspect ratio of 2 and a tank diameter of 6 m for the cold packed energy storage in liquid air energy storage systems, resulting in a round-trip efficiency of 50.3 %, a total capital cost of 86.86 M€ and a levelized cost of storage of 0.093 €/kWh, 0.306 €/kWh, and 0.519 €/kWh for off-peak electricity prices of 0 €/kWh, 0.1 €/kWh, and 0.2 €/kWh, respectively.