Degradation-aware multi-timescale planning of park-level integrated energy systems with heterogeneous electrolyzers and hydrogen storage

The transition toward low-carbon industrial parks requires electricity–heat–hydrogen integrated energy systems (EHH-IESs) with high renewable penetration. However, renewable uncertainty and electrolyzer efficiency degradation often lead to biased investment decisions and insufficient operational flexibility. To address this challenge, a degradation-aware planning and scheduling framework for park-level EHH-IESs is proposed. A mixed-integer linear programming model is developed that incorporates full life-cycle efficiency degradation and start–stop characteristics of heterogeneous alkaline and proton exchange membrane electrolyzers. In addition, a multi-timescale coordinated scheduling strategy is established in which electrolyzers, fuel cells, and battery energy storage jointly provide flexible reserve capacity, enabling coordinated short- and long-term operation of the hybrid electricity–hydrogen storage system. Case studies demonstrate that explicitly modeling electrolyzer degradation significantly affects optimal capacity allocation, avoiding overinvestment in alkaline electrolyzers and reducing life-cycle investment risks. Furthermore, the hybrid electricity–hydrogen storage architecture reduces the total annualized cost by 1.26% and 3.13% compared with single battery or hydrogen storage configurations, respectively. These findings indicate that integrating degradation-aware electrolyzer modeling with hybrid storage coordination is essential for achieving economically efficient, flexible, and low-carbon industrial park energy systems. • A planning model incorporating heterogeneous electrolyzer degradation was developed. • Refined models capture the complementary flexibility of ALK and PEM clusters. • Electrolyzers and storage systems enable multi-timescale reserves. • Hybrid storage outperforms single storage and quantifies hydrogen value.