Green hydrogen vs green ammonia: A hierarchical optimization-based integrated temporal approach for comparative techno-economic analysis of international supply chains

Abstract

Recent global trends have increasingly focused on sustainable and green energy solutions,transitioning away from fossil fuels. Green hydrogen (GH) and green ammonia (GA) have emerged as promising contenders for energy carriers in international supply chains. Our manuscript delivers a thorough comparative analysis of GH and GA, acknowledging the complex interrelations among synthesis, storage, distribution, and conversion processes. This evaluation also incorporates the variability of weather, energy demand, and the delays inherent in shipping, on both hourly and seasonal scales. The study features a detailed case analysis of nine international trading routes, utilizing a hierarchical optimization framework and conducting comparative economic evaluations. Additionally, the study delves into a sensitivity analysis, exploring factors such as economies of scale and the operational constraints of water electrolyzer. One of the key findings of our research is the identification of GA as a more favorable option for an international energy carrier, particularly when considering renewable energy's seasonality and intermittency. GA's superior storage and transportation properties significantly mitigate uncertainties within the supply chain, offering a more robust solution in the context of green energy transportation and logistics. Furthermore, the techno-economic analyses survey their impact on each supply chain and reveal the interconnectedness between each supply chain element – power, conversion, storage, and transportation.