Green ammonia is poised to be a key part in the hydrogen economy. This paper discusses green ammonia supply chains with a focus on market structures. The architecture of upstream and downstream supply chains is explored. Market structure prototypes in different stages are explored based on transaction cost economics and lessons from the energy industry. In the infancy, a highly vertically integrated structure is proposed to reduce risks and ensure capital recovery. A restructuring towards a disintegrated structure is necessary in the next stage to improve the efficiency. In the late stage, a competitive structure characterized by a separation between asset ownership and production activities and further development of short-term and spot markets are proposed towards a market-driven industry. Mixed structures combining multiple structure features are also discussed due to the dependency on actual conditions. Further, a multi-linear regression model is developed to evaluate the designed structures using a case in the gas industry, due to the commonality in vertical integration and data availability. Results indicate that high asset specificity and uncertainty and low frequency lead to a more disintegrated market structure, and vice versa, thus supporting the structures designed. In addition, evidence from the latest trends in the clean ammonia market also verifies the designed early structure. Besides, potential ways to accelerate market emergence are also discussed. We assume the findings and results contribute to developing green ammonia supply chains and the hydrogen economy.

The shift to a sustainable development has become an important issue in China. This paper discusses the role of green ammonia in promoting China's energy, environmental and economic sustainability which has not drawn enough attention. First, key challenges in China's energy transition, decarbonisation and regional sustainable development are explored. The coal-dominated energy consumption has placed great obstacles in achieving energy transition and led to massive CO2 emission since the large-scale industrialization. The high dependency on oil and gas import has threatened China's energy security. Imbalanced and unsustainable regional development is identified with data envelopment analysis. Second, the potential of green ammonia in meeting these challenges is analysed. Ammonia is examined to be a flexible and economic option for large-scale hydrogen transport and storage. Co-firing ammonia in coal power generation at 3 % rate is evaluated as an option for achieving low-carbon transition by 2030. Benefits of developing a green ammonia economy is discussed from energy, environmental and economic aspects. The practice can decline fossil energy consumption, enhance energy security, and facilitate renewable energy delivery and storage, industry decarbonisation, and regional development. We assume the findings and results contribute to addressing sustainability challenges and realizing a hydrogen economy in China.

Green ammonia production as an important application for propelling the upcoming hydrogen economy has not been paid much attention by China, the world's largest ammonia producer. As a result, related studies are limited. This paper explores potential supply chain design and planning strategies of green ammonia production in the next decade of China with a case study in Inner Mongolia. A hybrid optimization-based simulation approach is applied, considering traditional optimization approaches are insufficient to address uncertainties and dynamics in a long-term energy transition. Results show that the production cost of green ammonia will be at least twice that of the current level due to higher costs of hydrogen supply. Production accounts for the largest share of the total expense of green hydrogen (~80 %). The decline of electricity and electrolyser prices are key in driving down the overall costs. In addition, by-product oxygen is also considered in the model to assess its economic benefits. We found that by-product oxygen sales could partly reduce the total expense of green hydrogen (~12 % at a price of USD 85/t), but it also should be noted that the volatile price of oxygen may pose uncertainties and risks to the effectiveness of the offset. Since the case study may represent the favourable conditions in China due to the abundant renewable energy resources and large-scale ammonia industry in this region, we propose to take a moderate step towards green ammonia production, and policies should be focused on reducing the electricity price and capital investments in green hydrogen production. We assume the findings and implications are informative to planning future green ammonia production in China.