THERMOECONOMIC ANALYSIS OF LIQUID AIR ENERGY STORAGE SYSTEM

Liquid Air Energy Storage (LAES) is one of the methods to store energy, which takes the advantage of high expansion ratio of air from liquid state to gaseous state. It uses liquefied air to create a potential energy reserve, by storing air in liquid form at -196 degrees C, in insulated, unpressurized vessels and exposing them to ambient temperatures followed by an electricity generation process by driving a turbine. Off-peak electricity is used to liquefy air, and liquid air will be drawn from the tank, pumped to high pressure and used to drive a turbine to generate electricity when this stored energy is needed. Thermal storage loops (cold recycle) within the cycle as well as integration of waste cold (using the cold released during regasification of LNG) or waste heat (utilizing a waste heat stream during the expansion of air) are the key benefits of this technology and strengthen its competitive position among other energy storage methods. In this paper, a grid scale, long duration energy storage system based on the liquid air cycle has been analyzed. The performance of a modified LAES system is evaluated to find out critical components and processes, which have a major impact on overall system performance. An economic study has been conducted by assuming a grid-scale LAES operating in Turkish market. LAES appears to be a promising solution as long as its full potential is unlocked by integration of waste cold and waste heat, resulting in an energy dense and cost competitive easily scalable energy storage solution.