Impacts of partial-load service on energy, exergy, environmental and economic performances of low-temperature compressed air energy storage system

Abstract An energy analysis of the off-design operation of a low-temperature adiabatic compressed air energy storage system has recently been presented. However, it is still unknown how the partial-load operation of this system could affect its exergy parameters, economic feasibility, and environmental impacts. Therefore, this study investigates the effects of the partial-load service of a low-temperature adiabatic compressed air energy storage system on its technical (energy and exergy), economic and environmental performance. The findings of the study will be very useful for optimal energy management and bidding strategy determination of power plants using this technology as the storage unit. This will be primarily of more importance for an energy storage unit that is connected to a renewable power plant, and thus, is under higher risk of operating in off-design conditions. The results indicate that the energy and exergy efficiencies of the system at the nominal load can be as high as 65%, while at 30% load, neither of these can be higher than 45%. The economic analysis shows that in the Danish electricity system as the case study, the payback period can be as short as 12 years if the system continuously works at the nominal load while for 80% operation load, the payback period will be about 22 years. Similarly, the emission reduction level achievable by using the system significantly decreases if it works in off-design conditions.