What’s going to happen?
To achieve a properly functioning and safe, large-scale, underground energy storage with compressed air, there are several steps that must be followed.
The Engineering – the design
It all starts with designing the installation and the salt cavern where compressed air will be stored. Following this, permit applications must be made and the design elaborated down to the smallest detail. When the necessary permits have been granted, the actual construction begins.
Construction
The construction can roughly be divided into two parts: the underground salt caverns and the above ground associated installation. The salt caverns (large, solid cavities in the salt layers in the soil) are made by dissolving salt.
The salt caverns must then be prepared for compressed air storage. Once the salt caverns and the associated above ground installation / buildings are ready, tests will be conducted to ensure that everything is working properly. Only when the relevant licenses have been granted will the entire installation be put into operation.
More about the technique
In the case of the above-ground CAES installation, 220 MW of compression capacity is involved at the entrance. We will divide this capacity over four compressors of 55 MW each, retaining as much flexibility as possible. During the air compression process, a lot of heat is released. To cool this air before it enters the cavern, we use hybrid cooling towers, resulting in an application of both air and water cooling. As a result, the air temperature in the cavern is around 50 degrees Celsius. This is an ideal temperature to guarantee the stability and safety of the cavern.
During the operation of the CAES facility, in the storage phase, electricity is used to force air into the storage cavern. In the generation phase, the compressed air is released and heated to drive turbines, which produce electricity when needed. When supplying power back to the electricity network, we use two Turbine Expanders with a total capacity of 320 MW. As the air expands, it cools down; therefore, we must warm up the air again, ideally using hydrogen. As a result of this, we are one of the first to be able to apply hydrogen on a large scale and drive the hydrogen economy.
