Power generators are exploring how they can retrofit coal-fired power plants to enable co-firing with ammonia, part of their strategy to reduce emissions of carbon dioxide (CO2). The latest project to look at the concept is led by Mitsubishi Heavy Industries (MHI), which on Dec.  7 announced it has signed a memorandum of understanding (MOU) with a Chilean independent power producer to begin a feasibility study on ammonia co-firing at a power plant in Chile.

MHI, with support from Mitsubishi Power, will conduct the study to determine the supply of ammonia burners and other boiler facilities, along with additional equipment, necessary for ammonia co-firing. Phase 1 of the study, which will run through 2024, “will be a basic study for 30% ammonia co-firing to identify the problems involved,” according to a news release from MHI. Phase 2, from 2025 to 2026, “will be to consider solutions to the problems identified in Phase 1, and compile a detailed plan for demonstration of 30% ammonia co-firing.”

The groups on Wednesday said that after the completion of Phase 2, Guacolda will conduct demonstration testing at the plant and increase the co-firing rate.

Mitsubishi last year announced development of a gas turbine that could burn 100% ammonia, and also announced projects in Singapore and Indonesia. Japan’s largest power company, JERA, last year began a project to show the viability of co-firing ammonia with coal in a 1-GW unit of the 4.1-GW Hekinan Thermal Power Station. Japanese officials earlier this year announced funding of as much as $500 million to develop and demonstrate ammonia co-firing at both coal- and gas-fired power plants.

758-MW Plant Has Five Units
The coal-fired plant being used for the MHI research is located in Huasco, Atacama Region, about 435 miles north of the Chile’s capital, Santiago. The 758-MW facility has five units. MHI supplied the boiler, steam turbine, and other core facilities for the plant. The company’s experience at the facility led to the signing of the MOU for the study.

Jorge Rodriguez, Guacolda’s chairman, at Tuesday’s signing ceremony said, “A rational policy to reduce greenhouse gases should consider a gradual withdrawal from the use of fossil fuels, combining them with more climate-friendly energies such as green hydrogen, green ammonia and long-term storage technologies, in the most economical way possible but always safeguard the safety of the electrical system as a whole.”

Chile has set a target for carbon neutrality by 2050. The country plans to increase its use of renewable energy, with a goal of 70% of its power consumption from renewables by 2030. The country is considered to have a high potential to produce green ammonia, and Guacolda officials have said the use of green ammonia would only further its ambition to co-fire ammonia at power plants to cut emissions of CO2.

Masahiko Hokano, head of the SPMI Business Division at MHI said, “We are very honored to be able to proceed with this feasibility study on ammonia co-firing in Chile, which is highly proactive in decarbonization efforts and has great expectations from the world in terms of renewable energy and clean fuel derived from it. By combining MHI’s innovative ammonia co-firing technology with Guacolda’s deep technical knowledge and power plant management know-how, we are confident that we can contribute to the further acceleration of decarbonization in Guacolda, and consequently in Chile.”

Challenges for Ammonia Co-Firing
The main advantage of co-firing with ammonia at coal power plants is the accompanying reduction in CO2 emissions. However, research has shown that burning ammonia can lead to emissions of other greenhouse gases, including nitrous oxide (N2O). Since ammonia molecules include nitrogen, ammonia combustion generates N2O. An analysis by BloombergNEF (BNEF) found that the global warming potential of this technology is 273 times larger than that of CO2, across a 100-year timescale. The BNEF analysis also found that a coal-fired power plant retrofitted to co-fire ammonia at 50% or lower blend rates still emits more CO2 than a natural gas-fueled combined cycle power plant.

Widespread co-firing with ammonia would have a dramatic impact on the market for ammonia, according to a 2022 study from Wood Mackenzie. The group found that just a 10% ammonia co-firing in coal-fueled plants worldwide would lead to 200 million tonnes (Mt) of ammonia demand. The group said that represents a potential market of $100 billion by 2050.