Life cycle study quantifies low carbon intensity of green ammonia production

Researchers at the Council for Scientific and Industrial Research (CSIR) and the University of Stellenbosch have conducted a comparative life cycle assessment (LCA) to evaluate the environmental impacts of producing green ammonia at a coastal facility in South Africa. The study, published in ENGINEERING Energy (formerly Frontiers in Energy), outlines how this innovative production method could significantly contribute to global low-carbon fuel efforts.

The transition to low-carbon fuels, like green hydrogen, is essential for addressing climate change. However, transporting and distributing green hydrogen over long distances presents challenges due to its low volumetric energy density. To overcome this, converting green hydrogen into green ammonia offers a viable solution. The study specifically examined the greenhouse gas (GHG) emissions associated with green ammonia production, leveraging South Africa’s abundant renewable energy resources.

Key findings from the research include:

• The carbon intensity of producing green ammonia is 0.79 kg CO2-equivalent per kg of ammonia.
• This figure decreases to 0.28 kg CO2-equivalent per kg of ammonia if coproducts such as oxygen, argon, and excess electricity are sold and allocated a portion of the emissions.
• Excluding the embodied emissions of the energy supply system further lowers the carbon intensity to 0.11 kg CO2-equivalent per kg of ammonia.
• These results are equivalent to 0.60 kg CO2-equivalent per kg of hydrogen, which is well below the current threshold for low-carbon fuel certification.
• The comparative LCA covered the process from cradle to production gate.
• Electrolysis was identified as the major contributor to environmental impact, accounting for 68% of the total.
• The environmental evaluation showed that the main impact categories were particulate matter (55%) and global warming potential (33%).

These insights underscore the energy-intensive nature of electrolysis and the carbon intensity of the energy infrastructure required for green ammonia production.

The implications of this study are significant for both academia and industry. As the world moves toward net-zero carbon emissions by 2050, green ammonia production could play a crucial role. The research supports the adoption of green ammonia as a sustainable low-carbon fuel, provided that energy supply systems are rapidly decarbonized to further reduce emissions from manufacturing infrastructure.

This study was funded by the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH, as part of the project “Promoting a South African Green Hydrogen Economy (H2.SA).” The findings also informed recommendations for the G20 RD20 Task Force on the Life Cycle Assessment of hydrogen.

Journal: ENGINEERING Energy (formerly Frontiers in Energy)

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Cite this article: Stafford, W.H.L., Chaba, K.J., Russo, V. et al. Life cycle assessment of green ammonia production at a coastal facility in South Africa. Front. Energy 19, 1072–1092 (2025). https://doi.org/10.1007/s11708-025-1013-5