Among the ammonia synthesis processes, the cryogenic separation of nitrogen and the reactor for ammonia require significant time for the start-up. The cryogenic separation takes 10 hours, and the reactor needs 30 hours at least. Therefore, nitrogen and ammonia cannot be efficiently produced if the plant is operated based on a daytime-only electricity supply from PV. For the constant operations of these two processes in this study, electricity from solar power is utilized with an operating rate of 18.75%, and the rest power of 81.25% is supplied by the grid.