A Comparative Techno-Economic Analysis and Life-Cycle Assessment of Ammonia Production Processes Toward a Sustainable Energy Transition

Abstract

Many countries and especially Arab oil producing ones are working toward diversifying their energy mix and transitioning away from fossil fuels as part of their national and international sustainability and clean energy efforts. Lebanon has been facing increasing widespread electricity blackouts after decades of unsustainable electricity production policies and fundamental neglect on the energy sector, which led to drastic negative environmental impacts that demand instant action. Looking at the silver lining, ammonia has been used since the World War as a great fertilizer that aided humanity and pushed for its growth. Adhering to global efforts toward decarbonization and a diversified energy mix, ammonia can be utilized directly as a fuel and as an energy (hydrogen) carrier. Although ammonia does not have carbon dioxide in its structure, typical production routes contribute to 1-1.7% of global CO₂ emissions. Several works in the literature and industries, internationally and regionally, have set the goal to produce more environmentally friendly ammonia using renewable sources of energy and carbon capture technologies to reduce its environmental bill and enhance its role toward a sustainable energy transition. As a grounding step to contribute to making this a reality, this research study offers a comprehensive approach to assess the efficiency, competitiveness, and environmental friendliness of six ammonia synthesis configurations using a scenario analysis of Grey, Blue, Hybrid Blue, Enhanced Blue, Hybrid Enhanced Blue, and Green ammonia processes. This is done through a techno-economic analysis and life-cycle assessment using openLCA software performed for the six chosen ammonia production routes. Sensitivity analyses are developed to evaluate the effect of fluctuating prices of natural gas, ammonia, urea, and carbon dioxide credits on the economic feasibility of each configuration and to test the impact of varying natural gas leakage percentage on the environmental impact of each route. Finally, an analytical hierarchy process for a multi-criteria decision-making analysis was conducted with varied priorities of environmental and economic criteria. The results of this study allow the determination of the most efficient, competitive, and environmentally friendly ammonia synthesis process to be used for producing ammonia as a long-term clean energy source and a domestic industrial fertilizers production in Lebanon and the region.