Feasibility of electricity generation based on an ammonia-to-hydrogen-to-power system

Abstract

The transition from centralized electricity generation to distributed electricity, such as fuel cell power plants, is one of the promising strategies for decarbonization in the energy sector. However, the operation of hydrogen fuel cells could be problematic because liquefaction or compression processes for hydrogen storage are energy intensive and require high maintenance costs. In addition, if hydrogen in fuel cell-based power plants is supplied via natural gas steam reforming, direct carbon emissions to the atmosphere are caused. Therefore, this study investigates an ammonia-based electricity generation system through the sequential conversion of ammonia to hydrogen and hydrogen to power. This system can replace inefficient and costly hydrogen storage with the existing infrastructure of ammonia and reduce carbon emissions by using ammonia instead of hydrocarbon feedstock. With an ammonia price from the conventional production way, the system shows an electricity generation price in the range of 0.227–0.261 USD per kW h and a carbon intensity of 0.80–1.44 kgCO₂-eq per kW h which are not feasible at present. Because ammonia price and emissions during production are the most significant factors for the feasibility of the system, five different scenarios considering various ammonia production pathways are established. Based on the scenario analysis, the feasible conditions and countries in terms of both economic and environmental aspects are identified. In the most optimistic scenario, the electricity generation price and carbon intensity are calculated to be 0.134–0.150 USD per kW h and 0.16–0.28 kgCO₂-eq per kW h respectively, and the system can be competitive in 40 countries out of 134 countries.