Advanced Adiabatic Compressed Air Energy Storage for the Integration of Wind Energy

The large-scale generation of electrical wind energy is planned in many countries, but the intermittent nature of its supply, and variations in load profile indicate a strong requirement for energy storage to deliver the energy when needed. Whilst pumped hydro storage, batteries and fuel cells have some advantages, only compressed air energy storage (“CAES”) has the storage capacity of pumped hydro, but with lower cost and less geographic restrictions. Existing diabatic CAES plant lose heat energy from the cycle during compression, and which must be re-generated before the compressed air is expanded in a modified gas turbine. Adiabatic CAES, on the other hand, uses a separate thermal energy store during the compression part of the cycle. During the generation part of the cycle the thermal energy store is used to reheat the air, which is then expanded through a sliding pressure air turbine. This storage technology offers significant improvements in cycle efficiency and, as no fuel is used, it generates no CO2. This paper describes the work of 19 partners within the “AA-CAES” Project (Advanced Adiabatic – Compressed Air Energy Storage : EC DGXII contract ENK6 CT-2002-00611) committed to developing this technology to meet the current opportunities in the market.