A comprehensive process modelling, techno-economic and life cycle assessment of a power to ammonia process

Cuevas-Castillo, Gabriela A.; Michailos, Stavros; Hughes, Kevin; Ingham, Derek; Pourkashanian, Mohamed

Abstract

Ammonia is currently produced through H2 derived from fossil sources and hereby alternative low carbon ammonia routes are essential for mitigating emissions. The present study for the first time investigates the feasibility of the whole supply chain of a Power-to-Ammonia (PtA) assembly though comprehensive process design and modelling, techno-economic assessment (TEA) and life cycle assessment (LCA). The investigated system includes offshore electricity generation, hydrogen produced through water electrolysis, nitrogen production through cryogenic air separation unit (ASU), and the Haber–Bosch (H-B) ammonia synthesis loop. The Aspen Plus software has been utilised to establish the mass and energy balances of the synthesis while System Model Advisor (SAM) software has been used to model the offshore wind farm. The H2 conversion efficiency (H2-conv.), the ammonia energy efficiency (NH3-efficiency) and the specific energy consumption (SEC) have been considered as technical key indicators. Typical economic indicators such as Capital and Operating expenditures (CAPEX/OPEX) and minimum selling price (MSP) of ammonia have been calculated while the CML 2001 environmental impact assessment method has been applied for the whole assembly. Moreover, a sensitivity analysis is carried out to assess the influence of the main parameters on both TEA/LCA. The results showed an H2-conv and NH3-efficiency of 96 % and 49 %, respectively. Energy integration resulted in a power generation of 14.3 MW. The economic analysis revealed a levelized cost of ammonia (LCOA) of £687/tonne NH3 which is higher than the fossil based-ammonia price of £245/tonne. However, the economic sensitivity analysis shows that a 50 % reduction in the levelized cost of electricity (i.e., £33MWh) could decrease the LCOA to £361/tonne of ammonia while to break even with the fossil ammonia price an LCOE of £21/MWh is required. Based on the LCA, the global warming potential (GWP) of the PtA is reduced by approximately 94 % compared to the conventional fossil-based ammonia (152 vs 2445 kg CO2e/tonne NH3). Further reduction on GWP can be achieved by replacing offshore wind with nuclear power supply.
Overall, the investigated PtA assembly offer great environmental gains, but monetary support and/or technical improvements are required to improve its market competitiveness. The study presented new data on a novel low carbon ammonia process and the information generated can set the foundation for detailed engineering designs and inform policy making.

Citation

Cuevas-Castillo, G. A., Michailos, S., Hughes, K., Ingham, D., & Pourkashanian, M. (2025). A comprehensive process modelling, techno-economic and life cycle assessment of a power to ammonia process. Sustainable Energy Technologies and Assessments an international journal, 76, Article 104278. https://doi.org/10.1016/j.seta.2025.104278

• Journal Article Type: Article
• Acceptance Date: Mar 14, 2025
• Online Publication Date: Mar 22, 2025
• Publication Date: Apr 1, 2025
• Deposit Date: Mar 26, 2025
• Publicly Available Date: Mar 23, 2026
• Journal: Sustainable Energy Technologies and Assessments
• Print ISSN: 2213-1388
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 76
• Article Number: 104278
• DOI: https://doi.org/10.1016/j.seta.2025.104278
• Keywords: Ammonia; Power to ammonia; Global warming potential; Techno-economic analysis; Life cycle assessment
• Public URL: https://hull-repository.worktribe.com/output/5089550