As sailors know only too well, harnessing the wind at the right time isn't easy. A similar problem is posed by wind power plants, since they depend very much on weather conditions. If the issue is producing electricity in line with requirements, their suitability is conditional. Energy is not always needed just when the wind happens to be generating it. Conversely, the turbines may be sitting idle when electricity needs are high. 

Tried-and-tested technology 

One option in securing excess energy for later use involves compressed-air energy storage power plants (CAES). At times when enough power is available, compressed air is injected into subterranean caverns or porous rock layers. The pressure in such a storage facility can quite easily reach 100 bars. When the air escapes, it drives a generator via a turbine to produce electricity. Compressed-air energy storage is an already tried-and-tested technology, although it has one drawback: The efficiency of existing CAES plant technology – worldwide only two power plant projects have been realized – is below 55% since the emerging compression heat goes unutilized today. 

New storage system 

AA-CAES = Advanced Adiabatic - Compressed Air Energy StorageWith wind energy expanding, storage power plants will gain in importance in future, so that RWE is engaged in the further development of this technology. To the fore is an adiabatic CAES-concept, which recovers the heat that emerges during air compression, thus a higher efficiency of up to 70% shall be achieved. This so-called AA-CAES process (Advanced Adiabatic – Compressed-Air Energy Storage) places heavy demands on certain system components, which nowadays are not available in the supplier industry’s portfolio. For this reason RWE Power and GE have jointly investigated the feasibility of this new type of power plant concept and have provided the basis for a further development program:

Project ADELE