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This study considers the emissions implications of co-combusting imported ammonia in coal-fired power stations. The study adopts a supply chain approach, estimating the emissions reduction potential of 20% ammonia co-combustion in coal-fired power stations in the country of use, and the emissions associated with ammonia production in the country of origin. The paper considers the emissions implications of using different ammonia production technologies: Haber-Bosch (HB) ammonia production with hydrogen generated from steam methane reforming using natural gas (SMR), with and without carbon capture and storage (CCS); Haber-Bosch ammonia production with hydrogen generated from renewable sources; and fully renewable electricity generated ammonia. The empirical setting of the study is an ammonia supply chain encompassing Japan and Australia. The results show co-combustion of ammonia produced with SMR-HB provides no net benefit for the combined country emissions, as ammonia production related greenhouse emissions in Australia are equivalent to the emission reductions in Japan. In contrast, co-firing ammonia produced from fully renewable sources reduces emissions in the two countries in 2030 by 43 MT per annum. SMR-HB processes with varying levels of CCS reduce annual emissions by 16–34 MT. Based on the results, different policy options are suggested for managing the emissions associated with a Japan-Australia ammonia supply chain. • Japan actively pursuing ammonia/coal co-combustion to reduce power sector greenhouse gas emissions. • An Australia-Japan ammonia supply is examined at a country boundary emissions basis. • Choice of ammonia manufacturing approach has significant impact on emissions. • 40 MT pa saving in Japan offset by 39 ± 11 MT pa increase in Australia from Best Available Technology. • Only a fully renewable ammonia manufacturing process reduces emissions in both Australia and Japan. [ABSTRACT FROM AUTHOR]

Abstract: Environmental problems have been considered to be serious in the construction industry. Waste management pressures are pressing very hard with alarming industrial warming signals. Among the different types of construction and demolition wastes, concrete is about 81 percent of the volume of construction and demolition waste in Australia. To minimize the concrete waste generated from construction activities, recycling of concrete waste is one of the best methods to improve the environment. However, situations of concrete recycling in different countries vary considerably. Japan is a leading country in recycling concrete waste, with 100 percent recycling of the wastes that are used for new structural applications. This paper investigates the current concrete recycling situations in Australian and Japanese construction industries. A questionnaire survey and structured interviews were conducted. In comparing the current concrete recycling situations between Australia and Japan, it should be noted that major difficulties found from Australian and Japanese construction industries are on different phases of the transition to recycling of construction wastes. Therefore, it is suggested that the Australian construction industry should be: i) developing a unified policy in concrete recycling; ii) providing financial governmental support; iii) developing clear technical specifications or standards on the use of recycled aggregate for structural applications. [Copyright &y& Elsevier]