Optimization of wind-solar hybrid system based on energy stability of multiple time scales and uncertainty of renewable resources

The integration of renewable energy with the chemical industry has become a significant research area. A universal design method for wind-solar hybrid systems targeting stable loads was proposed, based on optimizing objectives such as system energy fluctuations, costs, and safety. It thoroughly investigates the impact of energy fluctuations across different time scales on energy storage systems. The study conducted in Qingdao indicates that when the optimal photovoltaic capacity ratio is 0.71, electricity costs decrease by 40 %, with hydrogen storage tank costs dropping by 52 %. Relying solely on a single time scale for energy fluctuations may not comprehensively represent the energy storage capacity and efficiency of the storage system, potentially leading to misjudgements in system configuration. Additionally, interannual variations in renewable resources have minimal impact on the wind-solar capacity ratio but significantly affect hydrogen storage tank capacity. Sensitivity analysis results reveal that the rated speed of wind turbines significantly influences system optimization, while fluctuations in equipment costs within 20 % have a minor effect on the wind-solar capacity ratio. Finally, several policy recommendations for the design of wind-solar hybrid power systems were offered, emphasizing the importance of wind-solar complementarity, the development of energy storage technologies, and the local utilization of renewable energy.