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.
Compressed air energy storage (CAES) is one of the many energy storage options that can store electric energy in the form of potential energy (compressed air) and can be deployed near central power plants or distribution centers. In response to demand, the stored energy can be discharged by expanding the stored air with a turboexpander generator.
The number of sites available for compressed air energy storage is higher compared to those of pumped hydro [, ]. Porous rocks and cavern reservoirs are also ideal storage sites for CAES. Gas storage locations are capable of being used as sites for storage of compressed air .
"Technology Performance Report, SustainX Smart Grid Program" (PDF). SustainX Inc. Wikimedia Commons has media related to Compressed air energy storage. Solution to some of country's energy woes might be little more than hot air (Sandia National Labs, DoE).
The compressed air storages built above the ground are designed from steel. These types of storage systems can be installed everywhere, and they also tend to produce a higher energy density. The initial capital cost for above- the-ground storage systems are very high.
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.