Technical and economic analysis of energy storage in the compressed air technology with low capacity for the production plant

Compressed air energy storage (CAES) system is a promising technology due to its numerous advantages, including relatively low maintenance cost, a long lifespan and high operational flexibility. This article explores the possibility of designing a CAES power plant as a source of electricity and heat for an existing industrial plant. The study involves the technical analysis of the power plant parameters and the economic analysis of the project’s feasibility. The proposed power plant is an innovative solution with an air expander with an external combustion chamber and a bypass that allows the combustion of virtually any fuel, making it particularly environmentally friendly. In the system, the use of a combustion chamber at the outlet of the turbine makes the chamber operate at a constant pressure that is close to atmospheric pressure. The designed power plant has a capacity of approx. 3.1 MW. Turbine operation reaches an efficiency of about 76%. Additional modification of the power plant and the use of heat from compressor cooling could increase the power of the power plant by about 0.5 MW. The conducted financial analysis showed that the project is economically feasible under the adopted assumptions in three modeled scenarios. Under the most optimistic scenario, the internal rate of return (IRR) reached 14.27%, and the investment return time was 10 years. When using long-term energy prices data, it was 7.46% and 23 years, respectively. The proposed CAES system is original and competitive in comparison to the currently used solutions.