Japan’s 4,500-gt Kiko Maru has completed a two-hour demonstration voyage in Osaka Bay using what is claimed to be the world’s first hydrogen-only marine engine, according to a statement from the Nippon Foundation.
The vessel covered about 33 km on 25 September using the pilot-ignition engine and cut CO2 emissions by about 1.2 tonnes compared with operation on conventional fossil fuel.
The Nippon Foundation said the development of a vessel fitted with a hydrogen-only engine and its demonstration voyage were world firsts, based on its own research as of September 2026.
The trial is part of the Zero Emission Ship Project, launched in 2022 to develop vessels with zero CO2 emissions as Japan targets carbon neutrality in domestic shipping by 2050.
Yanmar Power Solution developed the hydrogen-only engine and related hydrogen equipment through one of the project’s three consortia. Kiko Maru owner and operator Ueno Transtech carried out the vessel retrofit and trained crew for hydrogen-fuel operations.
The project previously achieved zero-emission operation of offshore wind service vessel Hanaria using hydrogen fuel cells in April 2024. Demonstration tests involving the other two consortia are planned by the end of fiscal 2026.
The Nippon Foundation is the organisation behind the Zero Emission Ship Project and coordinates its three development consortia.
Ueno Transtech is a Japanese corporation founded in 1869 with operations focused on energy transportation.
Yanmar Power Solution is a Japanese corporation responsible within the consortium for developing the hydrogen engine and associated hydrogen equipment.