Multi‐objective optimization of reservoir refill operate considering energy storage and hydrological conditions

Abstract Optimizing reservoir refill operation rules is crucial for enhancing reservoir sustainability and resilience. This study proposes a refill operation model designed to derive optimal refill guide curves by considering flood risk prevention, maximum storage levels, and the combined benefits of hydropower generation and energy storage. The proposed model was applied to the Longtan Reservoir in China. The results indicate that employing various optimal refill guide curves, tailored to wet, normal, and dry hydrological conditions, yields better outcomes than using a single refill guide curve. In wet years, the maximum annual combined benefits of hydropower generation and energy storage increased by 2.88%. In normal and dry years, the average annual water level at the end of the water storage period was significantly raised by 0.71 and 1.9 m, respectively. Correspondingly, the reservoir storage volume increased by 2.53 × 10 ⁸ m³ and 6.19 × 10 ⁸ m³, respectively. These findings demonstrate that the proposed approach can enhance the benefits of refill operations at the Longtan Reservoir under varying hydrological conditions.