Hydropower, an important renewable energy source worldwide, is threatened by reservoir sedimentation. Ecological restoration (ER) can mitigate this by reducing upstream sediment, thereby extending hydropower facilities' lifespan. However, ER may also reduce runoff, potentially diminishing energy generation and complicating its overall impact on hydropower potential. Here, we examine China's Yellow River, once the world's most sediment-laden river, using eco-hydrological and reservoir regulation models to assess how large-scale ER influences the hydropower potential of the Xiaolangdi Reservoir, which controls 92.3% of the basin area. Our results indicate that, excluding upstream reservoirs' operations and socioeconomic water use, Xiaolangdi could generate a total of ~2.7×10