Abstract: High electricity costs remain one of the primary bottlenecks limiting the large-scale deployment of wind-PV-powered hydrogen production. In wind-PV hydrogen production systems, the output characteristics of wind and PV power, the wind-PV-storage-load configuration ratio, and the grid-connected/off-grid operation mode will affect the utilization rate of wind and PV power generation and the electricity consumption structure for hydrogen production, thereby influencing the variable and fixed costs per unit of hydrogen production. This study develops a bi-level levelized cost of hydrogen (BLCOH) analysis model for grid-connected wind-PV-storage hydrogen production systems, explicitly accounting for the dynamic changes in renewable energy supply and hydrogen production electricity consumption. The model is applied to compare the cost performance of three system configurations: off-grid wind-PV hydrogen production, off-grid wind-PV-storage hydrogen production, and grid-connected wind-PV-storage hydrogen production. Furthermore, the impacts of renewable energy utilization hours, hydrogen production operating hours, and peak-shaving electricity pricing on hydrogen production costs are quantitatively analyzed. Results indicate that integrating energy storage improves renewable energy utilization and enables additional revenue through grid peak-shaving services, while grid connection enhances the operational reliability of hydrogen production systems. Among the evaluated configurations, the grid-connected wind-PV-storage hydrogen production system achieves the lowest hydrogen production cost, making it a promising pathway for future development. Additionally, this study provides analytical expressions for estimating critical thresholds of storage cost, grid electricity price, and the combined cost of storage and grid connection for wind-PV hydrogen production systems.

Key words: bi-level levelized cost of energy model, energy storage, hydrogen production system, wind and photovoltaic (PV) power generation