Coordinated optimization method for hybrid energy storage and renewable energy off-grid hydrogen production system incorporating electrolyzer adaptive power allocation

Off-grid hydrogen production powered by renewable energy offers a viable solution to address the insufficient grid accommodation of clean energy, serving as a critical pathway toward achieving carbon peaking and neutrality goals. However, the inherent volatility and intermittency of renewable sources induce significant power fluctuations, which degrade the efficiency and operational safety of alkaline electrolyzers. Even with energy storage integration, challenges persist, including harsh electrolyzer operating conditions and severe wind/solar curtailment. To address these issues, this paper proposes a coordinated optimization method for hybrid energy storage and renewable energy off-grid hydrogen production systems, incorporating adaptive power allocation for electrolyzers. First, power supply priorities are established based on electrolyzer operating states, enabling adaptive allocation of optimal power commands to optimize electrolyzer performance. Concurrently, reserved energy in storage systems is strategically managed to enhance annual power supply reliability and prolong storage lifespan. Subsequently, an improved multi-objective particle swarm optimization algorithm is employed to optimize hybrid storage capacity configuration, targeting minimized levelized hydrogen production cost and hydrogen deficit rate, thereby balancing system stability and economic viability. A real-world case study in northwestern China validates the proposed method. Results demonstrate that the approach significantly reduces electrolyzer downtime incidents and average power fluctuation rates, improves average hydrogen production efficiency by 7.9% and lowers the levelized hydrogen cost by 11.5%.