Global emissions implications from co-combusting ammonia in coal fired power stations: An analysis of the Japan-Australia supply chain

Abstract

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.