Potentialities of CAES (Compressed Air Energy Storage) and V2G (Vehicle to Grid) in the Electricity Market Optimization and in the Integration of Renewable Resources

The paper deals with the simulation and optimization of a Hybrid Power Plant (HPP) consisting of a wind turbine coupled with Compressed Air Energy Storage (CAES). According with the proposed plant lay-out, the wind power surplus is used to drive a multi-stage compressor to store compressed air in an air reservoir, while, in case of power demand, the compressed air is heated in multiple expansion stages using the stored heat and conventional thermal sources. Hybrid power plants can offer significant benefits in terms of flexibility in matching a fluctuating power demand, particularly when renewable sources, characterized by high and often unpredictable variability, are utilized. The possible advantages in terms of energy and cost savings with respect to other solutions must be carefully assessed, critically depending on performance and efficiencies of each sub-system, most of them operating in transient and off-design conditions. To this purpose, a thermodynamic model composed of several sub-systems describing wind turbine, multi-stage compressor, intercooler, aftercooler, heat recovery system, compressed air storage and turbine has been developed in Matlab/Simulink®. Operational and investment costs have been estimated, aiming to compare several plant scenarios with respect to the main control and design variables, evidencing economic and energetic performance and environmental impact