Evaluating effects of battery storage on day-ahead generation scheduling of large hydro–wind–photovoltaic complementary systems

Abstract

The complementary management of hydro, wind, and photovoltaic (PV) energy can effectively promote new energy consumption. However, the flexibility of hydropower is often inhibited by comprehensive water use in the river basin, which impairs the complementary performance of the system. Integrating battery storage into a hydro–wind–PV (HWP) complementary system is promising for enhancing the system’s flexibility, but it is unclear whether and how much battery storage can improve the complementary system. This paper proposes a methodology for evaluating the effects of battery storage on the system’s complementarity. First, a day-ahead generation scheduling model was established for HWP and hydro–wind–PV–battery (HWPB) complementary systems, and a two-layer nested framework is used to solve these models. Then, a fuzzy decision evaluation method is applied to quantify the improvements of battery storage on complementary performance. Finally, intraday joint operation strategies are proposed for the battery storage and cascade hydropower plants, and the influences of battery storage on the hydropower efficiency are discussed. Results using the clean energy base in the upper Yellow River basin indicated that: (1) battery storage with 10% capacity configuration ratio can improve the complementary performance of the system by 23.09%; (2) the operational risks are reduced by 98.18%, and the peak shaving performance and daily average delivered power are increased by 3.98% and 0.55%, respectively; and (3) the joint operation may reduce the hydropower efficiency in spring, summer, and autumn, setting the planned charge time period at a later valley load period can reduce or avoid this negative effect; however, the joint operation can improve the hydropower efficiency in winter, which can be further increased by setting the planned discharge time period at a later peak load period. Generally, battery storage can significantly improve the complementary performance of HWP systems, and the proposed joint operation strategies are effective in guiding the short-term operation of HWPB systems.