Co-combustion of ammonia in coal-fired power plants in ASEAN

Southeast Asia is home to a large and growing fleet of coal power plants. One proposed policy response is to support the deployment of ammonia co-combustion technology to reduce greenhouse gas emissions from coal power generation while continuing to meet growing electricity demand. The effectiveness of the technology depends on accurately assessing the emissions reduction potential of ammonia co-combustion. We quantify the emissions reduction potential of ammonia co-combustion for the ASEAN coal fleet, taking into account the carbon intensity of ammonia production across four different ammonia production technologies. We then compare net emissions with and without ammonia co-combustion with a modelled pathway for the Southeast Asia's coal power generation consistent with a ‘well-below’ 2 °C warming scenario. Our results show ammonia co-combustion could increase the cumulative emissions by 7 % relative to the continued use of coal when ammonia is produced using the present business-as-usual method of Haber Bosch incorporating steam methane reforming. We also find co-combusting with ammonia produced via electrolysis with renewable energy offers up to 43 % emissions reduction in the coal fleet, assuming a 40-year operating lifetime. However, even with widespread use of the technology, findings suggest early retirement or substantive emissions savings elsewhere in the economy will be required for emissions to be consistent with limiting warming to 2 °C. Rigorous assessment of CO₂ mitigation measures is critical in enabling policy-makers to choose ‘least regrets’ decarbonisation pathways for emissions intensive power generation technologies.