New ammonia co-firing system, IHI’s A-FIRES aims to cut coal plant CO2

Edited by ad hoc news New Releases & Launches Desk. Reviewed before publication on 06/15/2026 at 8:45 PM ET. Details in the imprint.

IHI is pushing its ammonia co-firing technology into the commercial spotlight with its A-FIRES ammonia co-firing system, a retrofit solution designed to let existing coal-fired power plants burn ammonia alongside coal to cut CO2 emissions while controlling NOx. The Japanese engineering group has spent several years testing ammonia as a fuel in utility-scale boilers and is now positioning A-FIRES as a practical option for power producers facing stricter decarbonization targets in the 2030s. According to IHI’s own technical outlines, A-FIRES is built around low-NOx burners, optimized mixing of ammonia and pulverized coal, and dedicated ammonia storage and supply equipment that can be integrated into existing boiler islands. An IHI Technical Review article describes the system as a scalable co-firing retrofit concept for large coal units.

How IHI’s A-FIRES ammonia co-firing works and what it promises

The core of A-FIRES is a burner and furnace configuration that can inject ammonia into a coal flame in a controlled way, maintaining stable combustion while suppressing thermal NOx formation and using the reducing properties of ammonia to cut NOx in low-oxygen zones. IHI’s published boiler studies show that when ammonia is injected in the appropriate burner layers and mixed correctly with pulverized coal and air, furnace temperatures and oxygen distribution can be tuned to keep combustion efficient while sharply reducing NOx at the boiler outlet. One recent numerical study of a large coal boiler with ammonia co-firing found that multi-layer ammonia injection at around 20 percent energy share could bring furnace outlet NOx below 10 ppm, while keeping furnace temperature near 1,800 K and oxygen concentration around 3.3 percent, suggesting that practical emissions control targets are achievable with this approach. The combustion analysis in the Scientific Chronicles of Engineering journal highlights how ammonia addition delays ignition, lowers peak temperatures and promotes NOx reduction in low-oxygen regions.

On the hardware side, A-FIRES combines modified or purpose-designed burners, overfire air ports and flue gas recirculation with upstream ammonia handling systems, including storage tanks, vaporizers, metering skids and dedicated piping. IHI emphasizes that the system is intended as a retrofit package that can be installed on existing boilers, using the original pressure parts and much of the balance-of-plant equipment, which reduces capital expenditure compared with building new gas turbines or entirely new ultra-supercritical units. For utilities and industrial power producers operating large coal fleets in Japan and across Asia, the company argues that such retrofits could extend asset lives while cutting CO2 emissions proportional to the ammonia co-firing ratio, since ammonia combustion itself does not emit CO2.

In practice, the decarbonization impact will depend heavily on how the ammonia is produced and transported. If the fuel is derived from natural gas without carbon capture, the lifecycle emissions benefits shrink; if it is produced using low-carbon hydrogen and renewable electricity, the net reduction can be substantial. IHI has therefore positioned A-FIRES not just as a standalone boiler solution but as part of a broader ammonia value chain that could include blue and green ammonia supply from partners in the Middle East, Australia and Southeast Asia, with long-term contracts to support stable power-sector demand. Japanese policymakers have highlighted ammonia co-firing as one of several transition technologies for thermal power, and IHI is one of the best-known engineering names attached to pilot projects in this field.

From an operator’s point of view, retrofit complexity is likely to concentrate in three areas: burner and furnace modification, ammonia storage safety and integration with existing environmental equipment. A-FIRES requires new or modified burners capable of handling the different flame characteristics and ignition delay of ammonia compared with coal, and the furnace must be tuned to avoid excessive unburned ammonia slip that could affect downstream equipment. On the balance-of-plant side, utilities will need to build or expand ammonia storage, typically as refrigerated tanks or pressurized vessels, with safety systems for leak detection and ventilation, plus truck, rail or ship unloading facilities depending on the supply chain. Electrostatic precipitators, flue gas desulfurization units and selective catalytic reduction systems will also have to be checked and possibly adjusted to match the new combustion chemistry, although IHI’s test data indicates that low NOx levels can be reached with a combination of in-furnace control and conventional SCR.

Regulators and investors will judge A-FIRES projects not only on direct emissions and safety but on economics. Ammonia is currently more expensive per unit of energy than imported thermal coal on most Asian benchmarks, and transporting large volumes requires specialized infrastructure. However, IHI is pitching the system as a way to meet mid-term emissions constraints without a complete rebuild of generating fleets, which could become attractive if carbon pricing, emissions performance standards or green procurement rules tighten. For power producers in Japan, where long-lived coal assets still provide a sizable share of baseload and mid-merit generation, ammonia co-firing may be evaluated against options like biomass co-firing, accelerated gas switchovers and investment in renewables plus storage. International engineering and energy trade publications have noted growing interest in such co-firing pilots across the Asia-Pacific region, even as critics question whether the cost and fuel supply challenges can be overcome at scale. A Reuters report on Japan’s ammonia strategy points out that co-firing trials are advancing but that commercial rollout will hinge on building a global low-carbon ammonia supply chain.

For IHI itself, A-FIRES fits into a broader portfolio of energy and industrial solutions that includes boilers, gas turbines, aero engines and infrastructure projects. The company has signaled in its medium-term management plans that low-carbon energy systems, including ammonia and hydrogen-related equipment, are expected to become a more important part of its revenue mix as global customers decarbonize. That puts the ammonia co-firing system in a strategic position as both a technology reference and a potential source of retrofit order backlog if power utilities commit to multi-unit rollouts. Shares of IHI (ISIN JP3134800006) closed on the Tokyo Stock Exchange at JPY 5,405 on 06/14/2026.

This article was a.i.-assisted and editorially reviewed. Product information without warranty; prices and availability may change at short notice. Not investment advice and not a buy or sell recommendation. Trading involves risk up to and including the total loss of invested capital.