A Hierarchical EMS for Aggregated BESSs in Energy and Performance-Based Regulation Markets

The battery energy storage systems (BESSs) have been increasingly installed in the power system, especially with the growing penetration rate of the renewable energy sources. However, it is difficult for BESSs to be profitable due to high capital costs. In order to boost the economic value of BESSs, this paper proposes a hierarchical energy management system (HiEMS) to aggregate multiple BESSs, and to achieve multimarket business operations. The proposed HiEMS optimizes the multimarket bids considering a realistic BESS performance model, and coordinates the BESSs and manages their state of charge values, according to their price penalties based on dynamically generated annualized cost. By taking part in the energy market and regulation market at the same time, the cost-performance index (CPI) of the BESS aggregation is greatly improved. The impact of photovoltaic generation on system performance and CPI is also studied.