Design of a compression process to improve the operational flexibility of compressed air energy storage: FlexiCAES

Abstract The energy transition towards sources of generation without CO2 emissions implies a firm commitment to non-dispatchable renewable energies such as solar photovoltaic and wind energy. To ensure the sustainability of the electrical system, it is necessary to develop energy storage technologies that are efficient, versatile and, in addition, that ensure their adaptation to the demand for variable power of the system. In the present work, compressed air energy storage (CAES) system based on compression trains in different configurations has been studied to demonstrate the feasibility of using compression trains in parallel. Through this type of configuration, it is possible to adapt the compression system to variable excesses of power, allowing the possibility of operating in conditions below the nominal ones. Thus, it is possible to consider different strategies to compress and expand in a day in order to use any excess or demanded energy. Two cases of study have been used (200 and 300 m depths) to illustrate how the FlexiCAES configuration would operate in three different operating ranges: from part load of 33% to full load conditions. FlexiCAES configuration might operate in any studied range whereas traditional configuration would only operate in an efficient way at full load condition.