Site sought for compressed air energy storage system

The major expansion in renewable energies is being accompanied by increasing fluctuations in the electricity grid. This challenge is to be met by high-performance, efficient electricity storage systems.  The German Federal Ministry of Economics and Technology is cooperating with RWE Power AG in supporting the "Adiabatic compressed air storage systems for electricity supply" project (German abbreviation: ADELE). Since November 2010, a salt dome in Staßfurt has been the first choice site for the first demonstration plant of its kind in the world. The project has a lot going for it, in the opinion of Prof. Dr. Gerd Jäger.

Construction of this demonstration plant is to begin in 2013. It is to have a storage capacity of up to 360 megawatt hours and supply an electrical output of up to 90 megawatts by 2016. ADELE should be able to quickly provide reserve capacity to the electricity grid without consuming additional fossil-fuel energy and thus without emissions. The project will be able to replace around 50 of the wind turbines typically used in the region for about four hours. It is planned that this research and development project, which is supported by the German Federal Ministry of Economics and Technology and has total funding of 10 million euros, will have developed the required technology by 2012, including materials testing and approval procedures. An expansion of the demonstration plant is possible if operation proves successful.

A lot is known about the structure of the salt dome from its use for gas storage and brine extraction. After appropriate modifications are carried out, an existing cavern could be used to store compressed air. In addition, Staßfurt is located in an area with a number of wind farms; during periods of low electricity demand, the excess energy could be used to fill the storage facility. The operating principle begins with the compression of air. The heat released here is stored temporarily and the air is then forced into underground caverns. When the electricity demand rises again, the compressed air can be used for power generation in a turbine, accompanied by the simultaneous recovery of heat.