Experimental evaluation of compressed air energy storage as a potential replacement of electrochemical batteries

This work reports on an experimental compressed air energy storage system used to run a three-phase electric generator to feed AC loads. The same loads are also supplied by a battery-inverter setup and both are compared in terms of performance and also from a physical footprint. At operating pressure of 10-12 bar and storage pressure of 80-100 bar, a 12 V battery is equivalent to 12 m3 of air storage space. This space is a function of the air motor power and also coupling with the generator, if it is direct or through a gearbox. The mathematical calculations estimated 27 % higher energy and power results, which are attributed to kinetic and mechanical losses in the air expansion and gearbox friction, respectively. This work is expected to pave the way for further experiments and innovation in specialized air handling turbines for large-scale energy storage. The physical footprint of the conversion system is relatively small, especially if provisions for storage tanks are made underground like gas station tanks.