The Azimuth Project
Compressed air energy storage (Rev #1)

Compressed air energy storage is a way of storing energy by compressing air when energy is available and extracting energy from the compressed air by letting it expand when energy is required (a bit like a spring). It has been used commercially with coal-fired plants since 1978 to smooth out peaks in demand. It is often advocated as a means of making intermittent sources of energy such as wind power more useful.

The main difficulty is doing it efficiently. Compressing air makes it hot, and it is easy to lose this heat energy, while letting it expand makes it cold, so it needs warming up again. Several technologies mitigate the problem in different ways.

References

CAES, Wikipedia.

A US nuclear future?, Nature, Vol 467, No. 7314, 23 September, 2010