MHIET Establishes Hydrogen Co-Firing Specifications for the KU Series Gas Engine for Power Generation
Mitsubishi Heavy Industries Engine & Turbocharger, Ltd. (MHIET), part of the Mitsubishi Heavy Industries (MHI) Group, has established hydrogen co-firing specifications for its KU Series gas engines, covering power outputs from 3.65 MW to 5.75 MW, and has begun proposing the technology to customers.
The KU Series engines are used in cogeneration systems across a wide range of industries. The new specifications are designed to enable these engines to operate with hydrogen alongside natural gas while maintaining stable combustion across the engine’s operating range.
MHIET had previously confirmed stable combustion at rated output with hydrogen co-firing of up to 50% by volume using a single-cylinder test engine for its 5.75 MW gas engine. However, practical operation requires stable performance under varying load conditions, while hydrogen combustion can create challenges such as knocking and pre-ignition.
To address these issues, MHIET used computational fluid dynamics (CFD) analysis and combustion reaction models to investigate the mechanisms behind abnormal combustion. Based on the findings, the company developed technologies to suppress knocking and pre-ignition across the operating load range and established specifications for hydrogen co-firing.
The specifications cover the complete cogeneration system, including the gas engine and integrated control system, rather than focusing solely on the engine itself.
The hydrogen-capable KU Series also allows operators to adjust hydrogen use according to fuel availability. By changing the operating mode, customers can switch from natural gas operation to their desired hydrogen co-firing ratio while the equipment is operating. This provides flexibility for customers whose hydrogen supply may vary over time.
MHIET has also minimized design changes compared with its existing natural-gas-only configuration. This means new installations can initially operate on natural gas and later be upgraded for hydrogen co-firing by adding the necessary equipment as hydrogen infrastructure becomes available.
The company said this approach allows customers to gradually increase hydrogen use while maintaining performance comparable to conventional natural-gas operation and supporting reductions in CO2 emissions.
The new technology can also be applied to existing KU Series engines. Customers currently operating KU Series gas engines on natural gas can retrofit them for hydrogen co-firing with relatively limited modifications, avoiding the need to replace the complete engine.
MHIET said the retrofit capability can increase the value of existing equipment while extending its effective operating life. The KU30A diesel engine can also be converted for hydrogen co-firing through conversion to a gas engine, providing another pathway for utilizing existing generation equipment as hydrogen availability increases.
Gas engines are widely used for on-site power generation at factories and institutions, as well as for district heating and cogeneration. Their high power-generation efficiency and strong load-following capabilities have also made them increasingly useful for supporting grid stability and power-wheeling services.
With electricity demand rising globally, MHIET expects demand for gas-engine power generation to remain strong. At the same time, the company is developing technologies that can support lower-carbon operation through hydrogen co-firing, hydrogen-only firing and the use of e-methane, or synthetic methane.
MHIET previously introduced hydrogen co-firing specifications for its 450 kW GS6R2 natural-gas engine. The addition of the KU Series expands the company’s portfolio of hydrogen-capable gas engines.
MHIET said it will continue expanding hydrogen-capable models across its gas-engine lineup, with the aim of increasing the value of distributed power-generation systems and supporting customers as hydrogen infrastructure develops.
