Abstract:

In weak-export grids with a high proportion of clean energy, the lack of sufficient outbound transmission capacity and limited flexible, adjustable resources significantly exacerbates the curtailment of wind and solar power during peak renewable generation periods. Additionally, the high penetration of clean energy further reduces the operating range of traditional synchronous generators, weakening grid regulation capabilities and increasing the risks to load supply reliability. These conditions intensify the interconnected challenges of renewable energy curtailment and load power shortages, making the conflict more complex and severe. Electrochemical energy storage emerges as a key solution for smoothing renewable energy fluctuations and addressing supply-demand imbalances. It plays a critical role in ensuring the safe, stable, and flexible operation of power grids. This paper proposes an optimized energy storage configuration and operational strategy designed to balance both load supply reliability with renewable energy utilization. First, this study focuses on clean energy systems with high renewable penetration, identifying two critical requirements: ensuring reliable load supply and maximizing renewable energy utilization. Based on these objectives, three risk assessment indices are established to evaluate grid balance, clean energy utilization, and load supply reliability. Second, leveraging the proposed risk assessment framework, objective functions, and constraints are formulated to address both load supply reliability and renewable energy utilization. A bilevel optimization model is developed. The upper-level model determines the energy storage planning and configuration, while the lower-level model optimizes the operational strategy of the energy storage system. This approach integrates the dual objectives of ensuring supply reliability and promoting renewable energy utilization. Finally, the feasibility and effectiveness of the proposed strategy are validated through four case studies conducted on a high-proportion clean energy grid in Western China. Results show that compared to strategies focusing solely on renewable energy accommodation or power supply assurance, the proposed strategy significantly improves both power supply reliability and renewable energy utilization rates. Additionally, it effectively reduces operational costs and enhances the economic efficiency of the power grid.

Key words: energy storage configuration, optimized operation, load supply reliability, clean energy absorption, mixed integer linear programming