Small-scale demonstrator of a cold thermal store for liquid air energy storage

Intermittency of renewable energy supply causes an issue for grid balancing, as electricity generation is not easily controllable. A method to balance power supply and demand is to store energy during low-demand periods and use it at high demand. Cryogenic energy storage (CES) uses liquefied gas as an energy storage and transfer medium. Recycling cold from the expansion to the liquefier is a way to boost the CES efficiency. As the cold release from the evaporation of cryogen happens at a different time than the gas liquefaction, such an exchange of low-temperature energy requires a thermal store. A small-scale demonstrator of a packed-bed cold thermal store for use in LAES, integrated with a refrigerated warehouse, was built and run under different thermo-hydraulic conditions. It was able to store 2.92 kWh with round trip efficiency of up to 0.650 when storing for 1 hour and 0.490 when storing for 24 hours.