An analysis of a large-scale liquid air energy storage system

Abstract

Liquid air energy storage (LAES) is a class of thermo-electric energy storage that utilises cryogenic or liquid air as the storage medium. The system is charged using an air liquefier and energy is recovered through a Rankine cycle using the stored liquid air as the working fluid. The recovery, storage and recycling of cold thermal energy released during discharge more than double the overall energy efficiency of the cycle. The demand on a storage plant in a grid support application is expected to be irregular and intermittent in response to fluctuating supply from intermittent renewable generators. This will complicate the storage of thermal energy and will mean the energy flow rates in the thermal store will vary from cycle to cycle and the state of charge of the store will also vary. This paper presents an analysis of the LAES cycle. The material and configuration of the cold thermal store is discussed in particular with reference to scale and measures to mitigate losses due to the irregular and intermittent duty cycle. The paper concludes with capital and levelised cost analysis of a reference 20 MW/80 MWh LAES plant and a comparison of the levelised cost with other storage technologies.

Liquid air energy storage (LAES) with packed bed cold thermal storage – From component to system level performance through dynamic modelling

“…CAES is limited by the availability of natural underground reservoirs, relatively inefficient compared to electrochemical batteries and it might needs tailored turbomachinery for adiabatic configurations. In recent years an alternative solution for grid-scale storagenamely liquid air energy storage (LAES)has drawn the attention of both academic and industry [7][8][9][10]. Liquid air energy storage comprises three distinct processes summarized in the schematic of Fig 1: during charging excess electricity e.g.…”

“…Both heat of compression and cold thermal energy from regasification can be stored and recycled to improve the efficiency of the overall system. Thanks to its unique features LAES overcomes the drawbacks of PHS and CAES: it is not geographically constrained, uses commercially available componentsthus reduced upfront costsand it integrates well with traditional power plants [9,11]. However, LAES needs further research to increase overall efficiency, store cold and hot thermal energy efficiently and increase response time.…”

“…Progressively, different LAES improvements have been presented [15][16][17] and a 350kW/2.5MWh pilot plantnow located at the University of Birminghamwas built to demonstrate the feasibility of the proposed design [8]. Cold thermal store was realized using modular packed beds with quartzite rocks [9] and operated at nearly ambient pressure to reduce material costs and diminish plant complexity. The data gathered from the LAES pilot plant shown that when cold thermal energy is recycled the round trip efficiency of the plant increases of about 50% compared with the case without cold recycle [8].…”

Recent Trends on Liquid Air Energy Storage: A Bibliometric Analysis

“…Compared to other energy storage systems, LAES guarantees higher volumetric energy density (214 Wh/kg) and no geographical constrains [6]. The system relies on well-established technologies that limit possible development risks and ensure long life to the system (30-40 years) [7]. Due to its great flexibility under different off-design operations, integration with other thermal processes such as waste heat/cold recovery enables the energy storage efficiency to be increased [8].…”

Editorial: Energy storage

“…The scheme outlined uses four 300 MW Francis pump/turbine units and the paper contains a wealth of engineering detail. Morgan et al (2015) describe an analysis of liquid air as an energy storage medium and their paper pays particular attention to the engineering design and cost of a plant. Liquid air energy storage is one of a number of potentially exciting technologies being developed for large-scale storage.…”