What is CAES?

Compressed Air Energy Storage (CAES) refers to the compression of air to be used later as energy source. Energy is stored during periods of low energy demand (off-peak), for use in periods of higher demand.

Until now wind energy was only available when the wind was blowing. The CAES plant will be able to store that energy in the form ofcompressed air.

Air can be compressed using a variety of technologies — from coal, oil, gas or wind energy. At the CAES plant a significant proportion of the energy that will be used will be from clean wind energies.

Benefits of CAES

A common criticism of renewable such as wind and solar is that the energy resources are not available on demand. Through the use of a CAES system, renewable energy can be stored whenever it is generated and released on demand.

CAES is an environmentally friendly technology. Since atmospheric emissions are and will continue to be a major issue for the power industry,the CAES environmental benefits are some of its most valuable attributes. Per megawatt emissions from CAES are about one-third of conventional fossil fuel generation plants. Throughout the CAES cycle, compression and combustion are separate processes, resulting in a reduced impact on the environment compared with conventional natural gas-fired plants.

Underground energy storage is regarded as being extremely safe.

Why use CAES?

Electricity cannot be stored directly but at grid level it can be stored indirectly through pumped hydro storage and compressed air energy storage.

When clean renewable energy available from wind is combined with CAES, we can optimise the energy captured at night and off-peak by compressing air into deep underground caverns. These can be either in rock structures that offer suitable permeability and porosity or salt caverns.

During the day when demand increases, the compressed air is brought to the surface and heated with clean natural gas to generate peak time electricity.

A CAES power plant is efficient running at as low as 10% and can go from idle to full power in less than 10 minutes. As well as using power from wind, when required other off-peak sources of electricity can also be used to compress the air.