The Evaluation of Optimal SOC Limit for Energy and Reserve Capacity Procurement in ESS

Abstract

There have been evolving load and generations, so that the structure of power system is dynamically complicated. An ESS (Energy Storage System) for the electricity grid is introduced in a wide range of the application fields as the alternative. Those application fields have vast potential to the financial benefits. Therefore, it is measured to provide the coordinated energy and reserve capacity procurement for the storage under various potential applications. This paper presents how energy and reserve capacity procurement in the ESS can be managed. The coordinated energy and reserve capacity procurement for the storage are constructed from two main parts. The first is an hourly charging and discharging operation algorithm of the ESS that generally co-operates with renewable energies, and supplies the uninterruptible power in case of contingency. The normal operation mode is considered for controlling the storage to contribute both peak-shaving and a high renewable penetration. In the second part, the evaluation of an optimal SOC limit that controls storing and releasing energy and reserve capacity is given. The problem can be seen as a heuristic ACO (Ant Colony Optimization) problem with the goals of both maximizing benefit and minimizing life-cycle cost of the storage.