Adiabatic compressed air energy storage technology

Adiabatic compressed air energy storage (ACAES) is frequently suggested as a promising alternative for bulk electricity storage, alongside more established technologies such as pumped hydroelectric storage and, more recently, high-capacity batteries, but as yet no viable ACAES plant exists. At first sight, this appears surprising, given that technical literature consistently refers to its potential as a promising energy storage solution and the fact that two diabatic compressed air energy storage (DCAES) plants exist at utility scale (Huntorf, Germany and Macintosh Alabama, USA), with over 80 years of combined operation. In this article, we discuss aspects of the main components that constitute a compressed air energy storage (CAES) system, the fundamental differences between how they operate in diabatic and adiabatic contexts, and the design challenges that need to be overcome for ACAES to become a viable energy storage option in the future. These challenges are grounded in thermodynamics and are consistent with evidence from pilot plants, where performance information has been made available. Finally, we suggest that adopting a whole systems design philosophy would maximize the chances of successful ACAES demonstration and discuss worthwhile areas of future research for both simulation and experimental studies.