Compressed Air Storage

Compressed Air Storage is a very old technology, but there are only two commercial plants in the world so far. One is in Germany, the other one in the USA. There are a couple of reasons for that, mainly cost and storage efficiency. During the compression the air heats up. Storing high pressure air at over 500 °C is technically difficult for a number of reasons and not very efficient.

Therefore the air is usually cooled down before storing it in underground caverns. But for discharging the energy it needs to be heated up again before expanding. This is done with natural gas burners, leading to low overall storage efficiency.

In the last few years though researchers from the ETH Zürich came up with ideas on how to improve the process. They created the company alacaes AG and are currently doing tests in the Swiss mountains.