Optimal Sizing of a Wind-Powered Green Ammonia Plant for Maritime Fuel Supply—A Case in the Greater Bay Area

Green ammonia has emerged as a promising alternative fuel for maritime decarbonization, owing to its carbon-free combustion, favorable volumetric energy density, and well-established logistics infrastructure compared to other alternatives. However, critical gaps persist in the development of an integrated fuel supply framework, which hinders the large-scale adoption of ammonia-fueled vessels. Therefore, this paper proposes an onshore wind-powered green ammonia plant located along the Gaolan–Yangpu feeder route. The plant comprises PEM electrolysis, nitrogen separation, Haber–Bosch synthesis, and storage facilities. An optimal plant configuration is subsequently derived through hourly simulations based on wind power generation and a priority-based capacity expansion algorithm. Key findings indicate that a stable ammonia supply—synchronized with monsoon wind patterns and capable of fueling vessels with 10 MW propulsion systems consuming around 680 tons per fortnight—requires a 72 MW onshore wind farm, a 63 MW PEM electrolyzer, 3.6 MW of synthesis facility, and 3205 tons of storage. This configuration yields a levelized cost of ammonia (LCOA) of approximately USD 700/ton, with wind turbines and electrolyzers (including replacement costs) accounting for over 70% of the total cost. Sensitivity analysis further shows that wind turbine and electrolyzer prices are the primary factors affecting ammonia costs. Although variations in operational parameters may significantly alter final configuration, they cause only minor (±1%) fluctuations in the levelized cost without significantly altering its overall trend.