Obayashi Corporation, Iwatani Corporation, and Komatsu Ltd. successfully conducted Japan’s first on-site proof-of-concept (PoC) test using a medium-sized hydraulic excavator equipped with a hydrogen fuel cell system (FC excavator). The test was carried out at the Joshin-Etsu Expressway (Rockfall Countermeasure) Kitanomaki (No.2) Construction Project, under contract from the East Nippon Expressway Company Limited Kanto Regional Head Office.
The need for carbon nuetral alternatives on the job site
Approximately 70 percent of CO2 emissions at construction sites originate from diesel fuel. In efforts to reduce these emissions, the introduction of hydrogen-powered construction equipment, alongside the adoption of biodiesel fuels and electrification technologies, is considered to be one effective approach.
Since 2023, Komatsu has been conducting PoC tests of its FC excavator, showing successful performance and high operability comparable to diesel engine-powered models, along with the added benefits of zero exhaust emissions and reduced noise and vibration. Compared to battery-powered models, hydrogen-powered systems offer higher energy density and output, making them a promising power source option for achieving carbon neutrality at job sites that use medium-sized hydraulic excavators.
Overview and results of the on-site PoC test
With support from the Nagano Construction Office, Kanto Regional Head Office, East Nippon Expressway Company Limited, the three companies carried out an on-site PoC test from December 10 to 23, 2025, at the Joshin-Etsu Expressway (Rockfall Countermeasure) Kitanomaki (No.2) Construction Project site (a temporary storage yard). The test involved using the FC excavator for relocating surplus soil and refueling of the onboard hydrogen tanks on-site. The aim was to assess the practical feasibility of the FC excavator on an actual construction site and to identify potential areas for improvement in hydrogen supply and refueling methods.
Based on the results of the test, the FC excavator demonstrated work performance equivalent to conventional diesel-powered models. The test also confirmed additional benefits, including reduced operator fatigue, reduced engine-induced vibration, as well as improved situational awareness due to lower noise levels.
There were also several challenges to commercialization that were realized during the testing phase, including the need for an increased onboard hydrogen supply and faster hydrogen refuelling. In addition, as the conditions of the construction site evolved alongside the project, it became clear what kind of job sites are suitable for the safe and efficient use of hydrogen-powered equipment, taking into account the legal regulations on hydrogen refuelling. These insights will be instrumental in shaping future implementation models and establishing criteria for site selection.
