Modeling and dispatch of advanced adiabatic compressed air energy storage under wide operating range in distribution systems with renewable generation

Advanced adiabatic compressed air energy storage (AA-CAES) is a scalable physical energy storage technology with great potential in peak regulation and renewables accommodation. Due to load fluctuation and limited volume of air tank and heat reservoir, the operating status of AA-CAES often varies in a wide range, which is called off-design or part load status, and thus the charging/discharging efficiency and generation capacity tightly correlate with the power level and storage states. This paper proposes a tri-state model of AA-CAES which meets the computational requirements of power system dispatch. Thermodynamics at the compression and expansion side can be characterized via either theoretical analysis or experiments, and the three storage states that impact charging/discharging power is calibrated by piecewise linear functions. By above construction, AA-CAES resembles a traditional battery storage except for the three correlated storage states and state-dependent charging/discharging efficiencies, while the thermodynamics related information is encapsulated in the piecewise linear approximation. As a result, the power system dispatch problem gives rise to a mixed-integer nonlinear program. An efficient linearization method is proposed, in which the number of binary variables involved is a logarithmic function in the number of breakpoints. IEEE 33-bus system is used to validate the proposed model.