Liquid air energy storage – A critical review

Liquid air energy storage (LAES) can offer a scalable solution for power management, with significant potential for decarbonizing electricity systems through integration with renewables. Its inherent benefits, including no geological constraints, long lifetime, high energy density, environmental friendliness and flexibility, have garnered increasing interest. LAES traces its origins to the first liquid air engine attempt in 1899 and liquid air for peak shaving in 1977. Subsequent advancements in the UK, China, and Japan, signify the progress in the field. However, prior discussions regarding LAES applications have been limited, primarily concentrating on coupled configurations while overlooking decoupled setups. This study provides a comprehensive review of LAES, exploring various dimensions: i) functions beyond load shifting, including frequency regulation, black start, and clean fuel; ii) classification of LAES configurations into coupled systems (standalone & hybrid) and decoupled systems (onshore/offshore energy transmission & liquid air vehicle); iii) challenges facing decoupled LAES, particularly efficiency and hence cost associated with liquid air production (∼0.6–0.75 kWh/kg), as well as low round-trip efficiency (∼20–50 %) related to high-grade cold recovery; iv) highlighting the potential of cold/heat recovery in standalone LAES to enhance thermo-economic performance (round-trip efficiency of ∼50–60 %, payback period of ∼20 years) and the integration of extra cold/heat sources in hybrid LAES for further improvement (round-trip efficiency of ∼50–90 %, payback period of ∼3–10 years). This review aims to provide a comprehensive understanding of LAES, address challenges across configurations, and promote the developments in LAES technology.