Chapter 4: Green Compressed Air Energy Storage Technology

Green Compressed Air Energy Storage (GCAES) is a new concept that combines thermal energy storage with traditional compressed air energy storage. The goal is to recover the heat of compression and reuse it during the expansion phase, thus eliminating the need for external heat. This chapter compares the overall performance of GCAES with its traditional Compressed Air Energy Storage (CAES) counterpart and estimates the amount of greenhouse gas reduction. Generally, a small change in one of the parameters of CAES systems can propagate to other factors, significantly altering the performance of the plant. A change in the system status can also alter the process parameters of the thermal sub-systems. The key process parameters are air and thermal fluid mass flow rates, temperature, and pressure of the system at each design point. These parameters can significantly influence the performance of a CAES plant. This chapter compares the effect of variations in these parameters on the performance of GCAES and traditional CAES plants with three stages of expansion. Thermodynamic model simulations were carried out over a pressure from 40 bar to 80 bar and hot water mass flow between 176 kg/s and 216 kg/s. The obtained results show that the net generated power for the GCAES and the traditional CAES systems are about 110 megawatts and 65 megawatts, with maximum efficiencies of 78.6% and 70.5%, respectively. This study also reveals that a GCAES not only makes accessible greater energy generation but can also reduce up to 80 tons of carbon dioxide (CO₂) per discharge cycle. This is equivalent to more than 270,000 tons of CO₂ emission per operating year for the modeled CAES plant.