Hydrogen Engine Generator Set Ready for In-house Evaluation

TOKYO, May 29, 2024 – (JCN Newswire via SeaPRwire.com) – Mitsubishi Heavy Industries Engine & Turbocharger, Ltd. (MHIET), a part of Mitsubishi Heavy Industries, Ltd. (MHI) Group, has been working on commercialization of hydrogen combustion engines as a key product to support MHI Group’s MISSION NET ZERO declaration that aims to achieve net zero emissions by 2040.

In 2021, MHIET established technologies to achieve stable combustion of 100% hydrogen in a single cylinder engine of 170mm cylinder bore and 220mm piston stroke developed from its GSR engine series through testing at Japan’s National Institute of Advanced Industrial Science and Technology (AIST).

As the next step toward commercialization, construction of a 6-cylinder hydrogen engine generator set(Note1) of 500kW-class output and of a hydrogen supply facility for supplying high-pressure hydrogen gas delivered on trailers to the generator set under reduced pressure has been completed. Starting with a trial run using Japan’s city gas, MHIET aims to confirm stable combustion at 100% load while running on hydrogen within this fiscal year.

As a part of this series of tests, a thorough evaluation of the newly-developed hydrogen engine will take place, including combustion stability, performance, and reliability. Considering the characteristics of hydrogen(Note2), an evaluation of the safety and other performance required for a generator set will also be conducted. The use of green hydrogen (produced using electricity derived from renewable energy with no CO2 emissions) is planned for the tests.

By basing the entire development process, from design to evaluation, at a single premise, it is possible to quickly implement improvements that the evaluation discovers. MHIET aims to accelerate the process for commercialization and is targeting FY2026.

Reciprocating engines have a unique structure allowing them to burn a variety of fuels. Hydrogen engines are considered a promising technology for the Energy Transition that is targeting carbon neutrality. In particular, generator sets that use a hydrogen engine can thereby contribute to the carbon neutrality of distributed power systems because they emit zero CO2 while meeting power needs. Through demonstration tests, MHIET endeavors to help achieve a carbon neutral society by expanding the use of hydrogen.

1A set of equipment required to generate electricity using a hydrogen engine, including a generator mounted on the engine’s output shaft, auxiliary equipment (piping systems for fuel gas, lubricating oil, cooling water, intake and exhaust gas, and a generator control panel) required to operate the generator set, and enclosures that house and protect the generator and auxiliary equipment.2Compared to natural gas, hydrogen is highly combustible and can ignite with an energy equivalent to static electricity and with a wider combustion range. Furthermore, because the molecules are small and leaky, hydrogen engine generator sets require strict safety measures such as redundant leak prevention, leak detection, a safe stop of the integral system, and ventilation to avoid gas accumulation.Previous Releases of MHIET’s Hydrogen Engine Development1. Stable Combustion of 100% Hydrogen on a Single Cylinder Engine

MHIET Conducts Combustion Test for Hydrogen Engine with Pure Hydrogen — Joint Project with AIST to Achieve Stable Combustion of 100% Hydrogen Fuel for a Carbon-free, Hydrogen Economy


Tested a single cylinder engine (cylinder bore 170mm, piston stroke 220mm) modified from a MHIET 4-stroke gas engine GSR series offered in 6-to-16 cylinders at Japan’s National Institute of Advanced Industrial Science and Technology (AIST). In a joint research project with AIST, stable combustion of 100% hydrogen fuel was achieved.

2. Test Operation of City Gas and Hydrogen Duel-fuel on Commercial Gas Engine for Cogeneration System

Successfully Conduct Test Operation of City Gas and Hydrogen Mixed-fuel Combustion in a Commercial Gas Engine for a Cogeneration System — Rated operation at 35% hydrogen mixed fuel burning ratio a first in Japan


Toho Gas and MHIET succeeded in rated operation at 35 vol% hydrogen mixed fuel in a test run, the first in Japan. The test was conducted at Toho Gas Technical Research Institute in Tokai, Aichi Prefecture, using one of MHIET’s existing gas engines.

3. Achieves Stable Combustion of up to 50 vol% Hydrogen for 5.75MW Gas Engine Cogeneration System

MHIET Achieves Stable Combustion of up to 50 vol% Hydrogen on Single Cylinder Test Engine


Using a KU series gas engine (3.65~5.75MW), a model well-proven in a variety of industries, a single cylinder engine developed based on a 5.75MW cogeneration system was tested. With the aim of lowering CO2 emissions, stable combustion with up to 50 vol% hydrogen admixtures at an output equivalent to its rating was verified.

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.

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