Sustainable energy integration: Enhancing the complementary operation of pumped-storage power and hydropower systems

Efficiently optimizing the joint operation of off-river pumped-storage power (PSP) and hydropower stations offers a substantial opportunity to enhance synergies in power generation, financial returns, and carbon emission reduction. However, integrating solar power, wind power, and hydropower poses challenges, notably in managing their intermittent nature. This study presents an innovative multi-objective optimization model designed specifically for the joint operation of off-river PSP and mass hydropower stations. The primary objectives of this model are to maximize hydropower benefits while minimizing residual load fluctuations, thus enabling the power grid's smooth accommodation of variable renewable energies. Utilizing the Multi-objective Salp Swarm Algorithm, this method effectively addresses the challenges posed by intermittent renewable energies. This approach improves hydropower output and reduces residual load fluctuations, fostering a synergistic relationship between off-river PSP and hydropower stations. Conducting a case study involving an off-river PSP station and 396 regulatable hydropower stations in China, this study utilized the practical operation scheme as a baseline. The findings underscore that the optimized operation scheme significantly enhances synergies, especially under the condition of reaching maximum power load. Compared to the baseline scheme, this approach demonstrates substantial improvements across vital metrics, including a 26 % increase in hydropower output, a 22 % reduction in residual load fluctuation, a 26 % boost in financial benefits, and a 25 % decrease in carbon emissions. By addressing load fluctuations and enhancing the integration of variable renewable energies, this study advances United Nations' sustainable development goal - affordable and clean energy, paving the way for resilient and eco-friendly energy systems.