UBE Mitsubishi Cement recently released an update on its commercial scale demonstration using ammonia as a fuel at its Ube plant. It is currently testing the use of ammonia in both the cement kiln and calciner at the site. It has set the aim of reaching a 30% coal substitution rate with ammonia in the cement kiln by the end of March 2025. It has described the project as a world first. Planned future work includes running ammonia combustion tests alongside post-consumer plastics.
The company announced the three-year project in mid-2023. Utilities company Chubu Electric Power has been working on it and UBE Corporation has been supplying the ammonia for the test. The scheme dates back to before Mitsubishi Materials and Ube Industries merged their cement businesses in 2022. Ube Industries previously took part in a government research project looking at the topic, running combustion tests and numerical analysis in small industrial furnaces.
Another ammonia research project in the cement sector was revealed in 2024 by Heidelberg Materials in the UK. The company was awarded just under €0.40m in funding by Innovate UK through its UK Research and Innovation (UKRI) fund, together with engineering consultants Stopford and Cranfield University. The 12-month feasibility study aimed to assess the use of ammonia as a hydrogen carrier and evaluate the most economical method of on-site ammonia cracking to generate hydrogen for use by clinker kilns. It also intended to investigate the various tiers of the UK's existing ammonia supply chain network for the suitable transportation, offloading and storage of ammonia.
The UK project explained that it was looking at ammonia as a hydrogen carrier due to its high volumetric energy density. This, potentially, makes ammonia easier and cheaper to store and transport than hydrogen. It pointed out that storing and transporting hydrogen is difficult and the chemical is expensive. It also noted that the volumetric energy density of ammonia is 45% higher than that of liquid hydrogen. The benefit of switching to a zero-carbon fuel was that it could cut CO2 emissions by the cement and concrete sector in the UK by 16%.
The attraction of ammonia to the cement industry is similar to that of hydrogen. Both are versatile chemicals that can be produced and used in a variety of ways. The production processes and supply chains of both chemicals are linked. The Haber–Bosch process, for example, uses hydrogen to manufacture ammonia. It can also be cracked to release the hydrogen. When used as fuels neither release CO2 emissions directly. This comes down to the method of production. Like hydrogen, there is a similar informal colour scheme indicating carbon intensity (Grey, Blue, Green and Turquoise). Despite the advantages listed above, the disadvantages of using ammonia include toxicity and NOx emissions, as well as the fact that there is little experience of using ammonia as a fuel. The worldwide ammonia market was bigger by volume in 2023 with production of just under 200Mt compared to hydrogen production of just under 100Mt.
Back in Japan, the national government has been promoting the use of ammonia technology for the power generation sector. It added ammonia to the country’s national energy plan in the early 2020s following research on running power plants with a mixture of ammonia and coal. The ambition is to build up levels of ammonia co-firing at power plants, develop the necessary technology and grow supply chains. This, it is hoped, will broaden, diversify and decarbonise the domestic energy mix and pull together a new international market too. Unfortunately, this strategy has had criticism. One study by BloombergNEF in 2022 estimated, for example, that the electricity cost of Japan-based power stations switching to firing ammonia by 2050 would be more expensive than generation from renewables such as solar or wind.
This explains why the ammonia project by UBE Mitsubishi Cement is leading the way. The interest by a European cement company shows that others are thinking the same way too. Yet again, the potential decarbonisation solution for cement is likely to lead towards more complex industrial supply chains. The next steps to watch will be whether a cement plant in Japan actually starts to co-fire ammonia on a regular basis and if any more ammonia projects pop up elsewhere around the world.
