Ann: Redflow Quarterly Update Q2 FY2021 and Appendix 4C, page-30

Compressed Air Energy Storage

Paul Breeze, in Power System Energy Storage Technologies, 2018

Abstract

Compressed air energy storage (CAES) is based around the gas turbine cycle. Surplus power is used to compress air using a rotary compressor and then store it, often in an underground chamber. When the power is required, it is released from the chamber and passed through an air turbine that generates electricity from the flow of high pressure air. Output from the plant can be boosted by burning natural gas in the high pressure air before it enters the air turbine, as would happen in a conventional gas turbine. However this has the penalty of producing carbon dioxide emissions, which the plain storage plant does not. More advanced plants can store heat during air compression and releasing it during the expansion phase. Only two commercial CAES plants have ever been built.

https://www.sciencedirect.com/topics/engineering/compressed-air-energy-storage

I too know very little of compressed air, yet the tech keeps being mentioned in energy storage options. imo all options should be fully investigated as old understanding doesn't discover new knowledge or create new alternatives.

I also explored wave energy. there are several systems that remain under development, not commercially viable, and there was one in WA. This latter was a failure and reliant on Govt grants.

many moving parts tends to waste a lot of energy and degrade the efficiency.