Japanese firms JERA and IHI Corp. have launched the world’s first large-volume fuel ammonia demonstration testing at JERA’s 1-GW Unit 4 of its 4.1-GW Hekinan Thermal Power Station in Aichi Prefecture, Japan.
The demonstration testing, which kicked off on April 1 and is slated to continue through June 2024, involves substituting 20% of Hekinan 4’s heating value with fuel ammonia. The project is an integral part of a four-year effort that began in July 2021, subsidized by Japan’s New Energy and Industrial Technology Development Organization (NEDO) to establish ammonia co-firing at a large-scale commercial coal power plant.
The demonstration testing seeks to evaluate “both boiler heat absorption and environmental impact characteristics such as exhaust gases,” JERA said. Specifically, it will look at “characteristics of the plant overall, investigating nitrogen oxide (NOx) emissions and confirming factors such as operability and the impact on boilers and ancillary equipment,” JERA said.
The NEDO project is especially significant because “it may offer a low-cost first step to quickly advance the decarbonization in countries like Japan that need thermal power generation as an adjustable power source to ensure a stable supply of energy,” JERA and IHI noted.
According to the companies, ammonia is an especially promising fuel for coal substitution, given that it emits no greenhouse gases when burned (the combustion reaction formula of ammonia is 4NH3 + 3O2 → 2N2 + 6H2O). While hydrogen offers similar benefits, it has a low transport efficiency owing to its low combustion calorific value per unit volume, and because hydrogen has a low density, it requires much energy for liquefaction. Ammonia can be liquefied at –33.4C, and it is already widely commercially available for uses such as fertilizer production, with infrastructure built out to support its production, storage, transportation, and handling.
“Furthermore, since ammonia and coal have similar combustion speeds, they burn well together, so replacing coal with ammonia can reduce CO2 emissions while maintaining the same amount of power generation,” JERA noted in April. In addition, “since this initiative can be carried out while using current equipment, it can be carried out quickly and at low cost. The ratio of fuel ammonia will then be increased step by step, with the ultimate goal of generating electricity using only ammonia.”
While the demonstration testing is ongoing—promising to firm its technical viability—JERA suggests a more pivotal challenge will be to ensure a vast supply of fuel ammonia to feasibly replace coal at its thermal plants. If 20% co-firing were to be maintained throughout the year, Hekinan would need an annual volume of about 500,000 tons of ammonia, it notes.
“To put that in perspective, Japan currently imports around 200,000 tons of ammonia annually. This means that the demand from a single power plant would be more than double the total imports of the entire nation. As we increase the ratio of ammonia to be burned and extend this approach to other coal-fired power plants, the procurement volume will only grow over time,” it says.
JERA has sought to fill this gap by investing in resource development further upstream and building partnerships with ammonia producers, transportation companies, and receiving and storage companies. The development and demonstration of ammonia-fired power generation facilities form a key part of this “value chain,” it says.