-- Commencing Proposal Activities for Hydrogen-Capable Solutions Supporting Energy Transition --
- With hydrogen co-firing specifications for KU Series gas engines widely used as a cogeneration system, MHIET contributes to the decarbonization of distributed power sources
- Available as a natural gas-fired system designed for future hydrogen co-firing, requiring only minimal modifications
TOKYO, Aug 27, 2026 - (JCN Newswire) - Mitsubishi Heavy Industries Engine & Turbocharger, Ltd. (MHIET), a part of Mitsubishi Heavy Industries (MHI) Group, has established a hydrogen co-firing specifications for its KU Series gas engines (output 3.65-5.75 MW), used in cogeneration systems across a wide range of industries, and has begun proposal activities.
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MHIET previously confirmed stable combustion at rated output with a hydrogen co-firing of up to 50% by volume (50 vol%) using a single-cylinder test engine for a 5.75MW gas engine for power generation.(1) Actual operations, however, require stable combustion across a wide load range. In addition, abnormal combustion such as knocking and pre-ignition(2), which are challenges in hydrogen-fueled engines, must be suppressed across the entire power range. To address these concerns, MHIET has used CFD (computational fluid dynamics) analysis and combustion reaction models to elucidate the mechanism behind these problems. Based on these findings, MHIET developed technologies to suppress abnormal combustion across the entire operating load range and established specifications for hydrogen co-firing operation. Furthermore, assuming use in a cogeneration system, the specifications are developed to support hydrogen co-firing for the whole system, including the engine and the integrated control system.
Features of the KU Series Gas Engine for power generation with hydrogen co-firing capability
1. Flexible operation according to hydrogen fuel availability
Changing the operating mode allows the operator to switch from natural gas-fired operation to any desired hydrogen co-firing ratio, even while the equipment is in operation. This enables flexible operation tailored to customers' hydrogen availability.
2. Supports the gradual expansion of hydrogen use
Design changes from the current natural gas-only specifications have been minimized, ensuring performance equivalent to existing natural gas-only operation. New installations can initially be configured for natural gas-fired operation while maintaining equivalent performance and later converted to hydrogen co-firing through addition of the required equipment. This allows MHIET to respond flexibly to customers' installation plans according to the state of hydrogen infrastructure, while also contributing to the reduction of CO2 emissions.
3. Hydrogen co-firing specifications enhances the value of existing engines and contribute to their continued effective use
KU Series gas engines can also be retrofitted for hydrogen co-firing with minimal modifications to the existing engine, eliminating the need for complete engine replacement. This allows customers currently using KU Series gas engines on natural gas to enhance the value and achieve continued utilization through hydrogen co-firing. The KU Diesel Engine (KU30A) can also be converted to hydrogen co-firing via gas engine conversion, contributing to the effective utilization of existing diesel equipment.
Contribution of gas engines to a low-carbon or decarbonized society and MHIET's initiatives
Gas engines, which offer high power generation efficiency and excellent load-following capability, are widely used as on-site power generation equipment in institutions and factories, and for district heat supply. In recent years, they have also been used to support grid stability and power wheeling service. With electricity demand increasing globally, the need for gas engines is rising. At the same time, by supporting hydrogen co-firing, hydrogen-only firing, and utilization of e-methane (synthetic methane), gas engine power generation systems help the realization of a low-carbon or decarbonized society.
MHIET previously released a hydrogen co-firing specification for the natural gas-fired GS6R2 engine with power output of 450 kW.(3) In addition to the newly established hydrogen co-firing specifications for the KU Series gas engine, MHIET will further expand the range of hydrogen capable models in its gas engine lineup, contributing to enhanced value in distributed power generation systems.
(1) For details on the confirmation of stable combustion at 50 vol% hydrogen, see the following press release. https://www.mhi.com/news/23110101.html
(2) Knocking and pre-ignition are types of abnormal combustion. Knocking is when ignition occurs too early or the compression ratio is too high, causing the unburned mixture (a blend of fuel gas and air that has not yet ignited inside the combustion chamber) to be compressed after the start of normal combustion, causing ignition to start before the flames reach, and causing a sudden rise in the pressure inside the combustion chamber. Preignition is when the combustion of the fuel-air mixture begins naturally prior to ordinary ignition, causing a rapid rise in pressure inside the combustion chamber. Frequent occurrence of either issue can cause damage to internal engine components.
(3) For details on the launch of the 450kW gas cogeneration system capable of hydrogen co-firing, see the following press release. https://www.mhi.com/news/25070402.html
Reference Material
* Contribution of MHIET's KU Series Gas Engine for power generation
Technical Review Vol. 62 No. 2 (2025)
"CO2 Reduction and Hydrogen Utilization Technology for Power Generation Gas Engine KU30GSI"
https://www.mhi.com/technology/review/abstract-62-2-100
About MHI Group
Mitsubishi Heavy Industries (MHI) Group is one of the world's leading industrial groups, spanning energy, smart infrastructure, industrial machinery, aerospace and defense. MHI Group combines cutting-edge technology with deep experience to deliver innovative, integrated solutions that help to realize a carbon neutral world, improve the quality of life and ensure a safer world. For more information, please visit www.mhi.com or follow our insights and stories on spectra.mhi.com.
Source: Mitsubishi Heavy Industries (MHI)
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