This study addresses the challenges arising from the high volatility and intermittency of wind and solar power, as well as the limited operational flexibility of alkaline electrolyzers, in an off-grid renewable-powered hydrogen-to-ammonia system. A model is developed for a large-scale wind–solar hybrid generation system integrated with hydrogen production, hydrogen storage, and ammonia synthesis. The model incorporates electrolyzer start-up and shutdown transitions, the associated energy consumption, variations in hydrogen production efficiency, and operational stability constraints of the ammonia synthesis process. A minute-level optimization strategy is proposed to maximize daily profit from ammonia production, and the resulting mixed-integer linear programming model is solved using a commercial solver based on the branch-and-bound algorithm. The results show that, with installed capacities of 100 MW wind power and 20 MW photovoltaic capacity, the split scheduling strategy outperforms the uniform scheduling strategy in both economic performance and renewable energy utilization. Notably, daily ammonia production increases from 595.11 to 663.45 t, daily ammonia sales profit rises from 564.32×104 to 633.76×104 CNY, and the curtailment rate decreases from 8.972% to 0.356%. Additionally, the total electrolyzer operating time increases from 275 to 310 h, while the number of start–stop cycles decreases from 100 to 84. Furthermore, multi-day simulations confirm that the proposed optimization strategy improves renewable energy utilization and yields greater economic benefits.
Bo et al. (Fri,) studied this question.