Optimizing pumped storage hydropower for multiple grid services

Abstract

As an energy storage technology with the largest installed capacity, pumped storage hydropower (PSH) supports various aspects of power system operations. Determining the value of PSH plants for providing various services and contributions to the power system has been a challenge. Despite the large potential benefits, it is often difficult to accurately model and assess all available value streams considering their trade-offs. To address the challenge, this paper presents a method to model and optimize small-scale PSH facilities at the unit level for stacked value streams from a broad range of grid services. The proposed method is generic and applicable to both fixed- and adjustable-speed technologies with different configurations, including separate and reversible pump/turbine as well as ternary sets. An innovative optimal dispatch is developed to optimally utilize the long-duration energy storage capability. Case studies of a small modular PSH system are designed and used to demonstrate and validate the proposed method. Case studies showed that the proposed methodology can effectively maximize the total benefits from stacked value streams. In particular, adjustable-speed and hydraulic short-circuit technologies can significantly increase the flexibility of a PSH plant in providing ancillary services.