Near optimal control for microgrid energy systems considering battery lifetime characteristics

Integration of renewable energy sources (solar, wind, hydro, etc.) in microgrid presents a great challenge to ensure power network stability and reliability due to their intermittent nature. Grid-level battery energy storage system (BESS) has been recognized as one of the promising solutions to meet this challenge as well as to participate in power system economic operation. In this paper, near optimal operation/allocation of BESS has been investigated with the consideration of lifetime characteristics. The problem is formulated as a single objective optimization to maximize the total system revenue by considering the lifetime characteristics of lead-acid batteries. Adaptive dynamic programming (ADP) is investigated to solve optimal control policy for time-dependent and finite-horizon BESS problems. A classical dynamic programming approach has also been studied to validate the proposed approach. Simulation results discuss the impact of battery lifetime characteristics on the total system revenue. The results show that the ADP can optimize the system operation under different scenarios to maximize the total system revenue.