Operating a Battery in a Hydropower-Dominated System to Balance Net Load Deviations

Decreasing costs of battery storage technologies make them a viable option for providing flexibility in power systems. In this paper, we study the operations of a battery in combination with cascaded hydropower in a system with uncertain net load due to wind power production. By simulating the operations of the combined system for a whole year by solving daily stochastic planning and real-time balancing problems, we show that the battery is only used when the hydropower system is under stress from large amounts of inflow and limited available storage capacity. The annual cost savings of adding the battery, including battery degradation costs, is 3,314 €, which is low compared to the investment costs of the battery. Since the inflow to the system follows a predictable seasonal pattern, the system operator should consider renting the battery storage from external sources, such as electric vehicles, instead of investing in a permanent battery.