Compressed air energy storage is the second biggest form of energy storage currently behind pumped storage. Compressed air energy storage involves converting electrical energy into high-pressure compressed air that can be released at a later time to drive a turbine generator to produce electricity.
Compressed-air-energy storage (CAES) is a way to store energy for later use using compressed air. At a utility scale, energy generated during periods of low demand can be released during peak load periods. The first utility-scale CAES project was in the Huntorf power plant in Elsfleth, Germany, and is still operational as of 2024.
Ideally the compressed air is stored in an existing geographical formation such as a disused hard-rock or salt mine (keeps cost down), rather than producing specialist surface piping, which can be expensive. How does compressed air energy storage work? The first compressed air energy storage facility was the E.ON-Kraftwerk’s
Air is compressed using compressors and is stored in the storage tanks. Over the surface storage tanks are used for lower rating and underground storage tanks are preferred in case of very high capacity plants. The compressor is run by the motor generator to which the excess available energy is fed.
It is expected that the UK will need to be able to store about 200GWh of electricity by 2020, to help support the grid that becomes more dependant on intermittent renewable energy sources. Compressed air energy storage could be a valuable tool in allowing us to hit these ambitious targets.
Appendix B presents an overview of the theoretical background on compressed air energy storage. Most compressed air energy storage systems addressed in literature are large-scale systems of above 100 MW which most of the time use depleted mines as the cavity to store the high pressure fluid.