Could emissions caps help or hinder low-carbon ammonia?
Ammonia is a key ingredient in the fertilizers that farmers depend on — and a chemical with a hefty environmental footprint. In Europe, producing ammonia generates 36 million tons of carbon dioxide each year.
Most of those emissions come from steam methane reforming: an energy-intensive process that transforms natural gas into the hydrogen required to make ammonia. Shifting to electrolytic hydrogen — creating by splitting water — offers a greener alternative if it uses electricity from renewable sources. But is it economically viable, especially under increasingly stringent carbon emissions caps?
To find answers, WISE researcher Zhongming Lu and a group of international colleagues calculated the cost of switching to electrolytic hydrogen for 38 major European ammonia plants. The investigators factored in regional electricity prices, grid emissions and renewable potential, as well as different emissions caps that determine how much the plants could supplement onsite renewable sources with grid electricity.
Their results revealed that shifting to electrolytic hydrogen with no emission cap would slash emissions an average of 85 per cent.
Imposing a cap of 1 kilogram of CO2 equivalent per kilogram of hydrogen would achieve further reductions, cutting emissions by 95 per cent. In renewable-rich areas, the costs would be similar to steam methane reforming.
However, targeting 100 per cent emissions reductions would dramatically increase costs, and the amount of land required to build renewable energy infrastructure, likely hindering the transition to electrolytic hydrogen.
These insights can help European policymakers identify cost-effective decarbonization targets and regional strategies to support a sustainable ammonia industry.
Now the team is finalizing a new study that compares two strategies—grid connection under emission caps versus increased operational flexibility—to evaluate both cost and emissions reductions, ultimately providing science-based evidence for transforming existing ammonia plants. Future research will focus on the techno-economic analysis of emerging hydrogen production (e.g., biohydrogen) and supply solutions (e.g., decentralized) in Canada to address growing demand in areas like transportation, heating, and synthetic fuel production.
Researchers: Stefano Mingolla, Paolo Gabrielli, Alessandro Manzotti, Matthew J. Robson, Kevin Rouwenhorst, Francesco Ciucci, Giovanni Sansavini, Magdalena M. Klemun & Zhongming Lu
Partners: Hong Kong Research Grant Council, Hong Kong University of Science and Technology
Source: Mingolla, S., Gabrielli, P., Manzotti, A., Robson, M., Rouwenhorst, K., Ciucci, F., Sansavini, G., Klemun, Magdalena., & Lu, Z. (2024). Effects of emissions caps on the costs and feasibility of low-carbon hydrogen in the European ammonia industry. Nature Communications, 15(1), 1-23.