Introduction The efficiency of existing compressed air energy storage is not high enough, and the site selection is limited by the gas storage condition, which is not beneficial to the large-scale replication of compressed air energy storage. In order to improve the efficiency of compressed air energy storage, a gas turbine-based binary cycle gas compression energy storage system was proposed.
Method The compression and expansion process of the gas turbine was decoupled, and dual-working substance gas storage system with constant pressure variable volume operation method in a gas chamber was utilized. Energy storage and power generation could be realized through coordinated operation of the air working substance energy storage loop and CO2 working substance energy storage loop. Preliminary thermodynamic calculations and engineering feasibility analysis were conducted on the binary cycle gas compression energy storage system based on 50 MW industrial gas turbine.
Result The results show that the energy storage efficiency of the system is about 80%, reaching the level of pumped hydro energy storage, higher than that of conventional gas compression energy storage, but lower than that of lithium-ion battery energy storage. The cost level of the system is between pumped hydro energy storage and lithium-ion battery energy storage, slightly lower than that of salt cavern compressed air energy storage.
Conclusion For regions with abundant fuel resources such as natural gas and hydrogen energy, the gas turbine-based binary cycle gas compression energy storage system can be applied in the scenarios such as high energy consuming industries, new energy bases, and electricity grid, and it has good engineering feasibility as well as commercial competitiveness potential.
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