Transient modeling of a green ammonia production system to support sustainable development

Wind power intermittency makes it imperative to conduct transient modeling to highlight and address the challenges related to longer-term dynamics prior to demonstration projects. This paper presents the transient modeling and simulation of offshore wind energy integrated with a “green hydrogen” and “green ammonia” synthesis system. Since the transmission of electricity produced from far offshore sites to onshore points is challenging and submarine power cables are a significant cost, a fully off-grid offshore location is proposed for green ammonia production (power-to-ammonia) in contrast to previous studies that have examined grid-tied approaches. This approach can utilize the massive unexploited potential of remote offshore locations where wind velocities and capacity factors are comparatively higher, with produced green ammonia transported to onshore demand points via pipelines or ships. The offshore wind energy can directly be converted into ammonia using water and air as input materials, starting with the generated wind power used in the water electrolysis system to split water into hydrogen and oxygen. Nitrogen is separated by an air separation unit and mixed with the hydrogen to produce ammonia through an all-electric ammonia synthesis system. The transient analysis results include ammonia production at each hour of the year and an integrated hydrogen storage system to buffer production for nominally steady ammonia ouput throughout the year. An economic analysis is also conducted that reveals offshore wind and electrolysis as the leading cost drivers.