Techno-economic analysis of coal-fired with green ammonia co-firing power system devoted to lower carbon emission

Coal-fired power plants are currently an important electricity source but have high carbon emissions. A coal-fired with green ammonia co-firing power system can realize low carbon emissions while consuming excess renewable energy, which has potential research and application value to achieve carbon peak and carbon neutrality. In this study, a coal-ammonia co-firing system model for hydrogen production and consequent synthesis of green ammonia using wind and photovoltaic power is constructed to analyze its techno-economics. Taking the levelized cost of electricity and carbon reduction ratio of coal power units as evaluation criteria, multi-objective optimization of system composition and capacity setting is carried out. The results show that the optimal combination and capacity of system components vary by the decision-maker's preference, and the optimal cost for a 20 % carbon reduction ratio is 0.124 $/kWh for a conventionally sized power plant. Green electricity can be sustained by energy storage, and the ratio of storage to renewable energy capacity should be increased to achieve inter-seasonal power peak transfer. Increased carbon reduction ratio improves the green electricity supplied to the grid, but also increases energy waste. This study is informative about pathways for coal-fired power plants to achieve a low-carbon transition through co-firing.