Modelling of the Annual Performance of a CAES Plant and Relative Economic Analysis

Compressed air energy storage (CAES) technology can offer a lot of ancillary services to the electricity system such as black start capability, voltage and frequency support, integration with non-programmable renewable energy sources. CAES plants often operate on electricity spot markets by storing energy when prices are low and generating electricity when prices are high. This paper investigates the operation over a year of two different CAES plants in two different scenarios. The first scenario simulates the operation of a CAES plant as independent plant in the Italian electricity market with the aim of maximizing the earnings. The control method is based on the variation of the hourly price of energy and on the variation of the pressure of the air stored in the cavern. The second scenario simulates the operation of an integrated system built up of a CAES and a wind farm with the aim of maximizing the earnings of the integrated system and the capacity factor of the wind farm. The integration of CAES and the wind farm is considered by means of a non-direct connection. The spot markets prices are referred to the Italian market. Other ancillary services are not taken in consideration. The software used to conduct the simulations is Simulink, a dynamic package of Matlab.