Decarbonizing of power plants by ammonia co-firing: design, techno-economic, and life-cycle analyses

Abstract

This research investigates the decarbonization of India’s electricity grid using ammonia in power plants. It focuses on ammonia produced in Western Australia and transported to India, co-fired with high rank coal, and compared with power plants utilizing carbon capture and sequestration (CCS). The study assesses the overall costs and the life cycle greenhouse gas (LC GHG) emissions for both new plants and retrofits. For 20% gray, blue, and green ammonia, the levelized cost of electricity is 86, 89, 125 $/MWh, with corresponding LC GHG emissions of 1,234, 1,079, and 1,062 kg CO2e/MWh. Co-firing with green ammonia, though more expensive than blue ammonia, yields lower CO2 emissions. Conversely, reducing the same amount of direct CO2 emission via CCS costs $84/MWh and a LC GHG emission of 1,227 kg CO2e/MWh. While CCS is cheaper, it results in higher LC GHG. There is a trade-off between cost and emissions across the strategies. Under scenarios with low capacity factors or reduced ammonia production costs, coal-ammonia co-firing could become more economical and greener than the CCS. This study provides quantitative insights for policymakers and project developers. However, it is crucial for decision-makers to consider several factors: (1) the potential impact of social resistance to CCS; (2) the time required for large-scale commercialization of CCS technology, which is expected to be significantly longer than the implementation time for a coal-ammonia co-firing decarbonization strategy; (3) the potential of either CCS or ammonia-coal co-firing strategy to enhance India’s electricity mix, thus contributing to energy security.