Japanese trading house Marubeni recently conducted the world's first international transport of hydrogen using a metal hydride alloy, a material that can store the gas and enable more efficient shipping.
The Demonstration Project
The alloy absorbed "green" hydrogen produced in Australia and was then shipped by container vessel to Indonesia. Marubeni took around a year to clear customs procedures and other regulatory hurdles.
The shipment from Australia in October 2025 was transported by truck to an industrial site outside Jakarta. There, Marubeni successfully extracted green hydrogen from the alloy and generated electricity with fuel cells.
"It was challenging, because there's no precedent for this," said senior commercial officer Seiichiro Aoyama of Marubeni's new energy department, which led the project. "But it was significant that we were able to demonstrate the costs and the safety measures required for transporting metal hydride alloys."
Why Green Hydrogen Matters
Green hydrogen, which is produced using renewable energy, is a promising next-generation fuel that could play a role in the transition away from fossil fuels. But procurement costs have been a persistent challenge. Various efforts are being made to produce hydrogen in regions with access to cheap renewable energy and transport it elsewhere.
Current Transport Challenges
Gaseous hydrogen occupies a large volume, so it is generally compressed or liquefied for transport. Compression offers only limited improvements in transport efficiency, while liquefaction comes with cooling costs and results in some vaporization during transport.
Efforts are also underway to transport hydrogen in the form of ammonia, created by reacting the gas with nitrogen. But ammonia is toxic and has a strong odor, creating additional challenges.
The Metal Hydride Solution
Marubeni focused on metal hydride alloy technology. The special alloys absorb hydrogen under pressure or when cooled, releasing it when depressurized or heated. While the alloy itself is heavy and ill-suited to long-distance transport, it has low maintenance costs and minimal energy loss.
The key alloy used in Marubeni's project was based on technology developed by an Australian company. The exact composition is undisclosed, but it is an iron-titanium alloy that absorbs hydrogen under pressure. Marubeni developed a storage device in which the alloy is packed into slender cylinders about 5 meters long and roughly 17 centimeters in diameter.
Storage Specifications
Each cylinder can store about 4 kilograms of hydrogen, equivalent to 50-60 kilowatt-hours of electricity — roughly one to two days' worth of power consumption for an average household. In theory, the containers can absorb and release hydrogen about 1,000 to 1,500 times.
Container Shipping Innovation
To improve transport efficiency, Marubeni chose to use standard shipping containers. The company developed a mechanism to load the cylinders into the 20-foot containers used worldwide in maritime shipping, enabling them to be transported along with other cargo on container ships. Because container shipping costs are based on volume rather than weight, this approach helps offset the disadvantage of the alloy's heaviness.
For the demonstration project, only one cylinder was used, but in theory a single container could hold at least 30, according to Marubeni.
Safety Advantages
Compressed hydrogen requires special high-pressure tanks and other equipment, and is regulated as a hazardous and flammable gas in Japan. Metal hydride alloys, by contrast, have a lower risk of exploding.
Even so, Marubeni took extensive safety precautions because there was no precedent for international transport. Hydrogen is lighter than air and naturally rises, so the storage system was designed in a way that any leaked gas would dissipate naturally through ventilation at the top.
"There were many things we learned that will lead to future business," Aoyama said.
The Customs Challenge
The most significant challenge involved customs approval. The alloy contains such materials as titanium, which have intrinsic resource value.
"It was difficult to explain that the alloy was simply a 'container' for hydrogen," Aoyama said.
If classified as a raw material, the alloy itself would be subject to tariffs. While the hydrogen was subject to tariffs, proving how much was actually stored in the alloy took considerable time. Marubeni spent around a year consulting with customs authorities in both Indonesia and Australia to secure approval.
Commercial Viability Questions
Despite overcoming these hurdles, Aoyama warned that "at present, it's difficult to scale this as a business." Australian green hydrogen is relatively inexpensive, and the container transport improves efficiency. But the economics of the supply chain do not add up without stable, repeated demand for hundreds of shipments. The transport to Indonesia was conducted just once, and plans for future shipments are undecided.
Future Applications
Based on the trial, Marubeni is now envisioning container-based transport to remote islands. Multiple containers equipped with storage systems could be transported by ferry and installed directly on islands, where they could be used for emergency power with fuel cells in natural disasters and other emergencies. Because metal hydride alloys require no energy for storage, the company sees them as well-suited for long-term stockpiles.
Government Support and Framework
Marubeni's demonstration was chosen in 2021 to receive a subsidy from the Japanese Ministry of the Environment. It used green hydrogen production facilities built by Marubeni near Adelaide in southern Australia, a region with abundant solar energy. The subsidy aimed to use Japan's Joint Crediting Mechanism (JCM) to explore the potential use of carbon credits generated by the use of green hydrogen in Indonesia, one of Japan's partner countries in the JCM framework. Marubeni believes that the success of the trial could lead to other JCM business opportunities.
International Expansion Prospects
"Once we get approvals from Australia, similar projects are more likely to be approved in Europe, including the U.K., and in the U.S.," said Zuquan He, manager of hydrogen and ammonia business development at Marubeni.
Comparison of Hydrogen Transport Methods
Compressed gas: Limited efficiency gains; requires high-pressure tanks and hazardous material handling.
Liquefied hydrogen: High cooling costs; vaporization losses during transport.
Ammonia conversion: Toxic and odorous; additional safety and handling challenges.
Metal hydride alloy: Low maintenance; minimal energy loss; lower explosion risk; compatible with standard shipping containers.
Key Technical Specifications
Cylinder dimensions: 5 meters long, approximately 17 centimeters in diameter
Hydrogen storage per cylinder: 4 kilograms
Energy equivalent: 50-60 kilowatt-hours per cylinder
Cycle durability: 1,000-1,500 absorption/release cycles
Container capacity: At least 30 cylinders per 20-foot container
Alloy type: Iron-titanium base, absorbs hydrogen under pressure
Strategic Implications
The Marubeni trial demonstrates that metal hydride alloy transport is technically feasible, but several challenges remain before commercial viability:
Regulatory frameworks: Customs authorities worldwide will need clear guidelines for classifying hydrogen-bearing alloys.
Demand scale: Hundreds of regular shipments are required to justify supply chain economics.
Weight penalty: The alloy's heaviness remains a fundamental constraint on transport economics.
Safety certification: International standards for alloy transport need to be established.
Carbon credit integration: JCM framework could provide financial mechanisms to support early deployments.
Island Economy Applications
The vision of hydrogen-powered emergency systems for remote islands represents a compelling near-term market. Islands dependent on diesel generators face high energy costs and fuel supply vulnerabilities. Metal hydride systems could provide:
Emergency backup power: Resilience during natural disasters when fuel supply chains are disrupted.
Long-term storage: No energy required to maintain hydrogen in the alloy.
Scalable deployment: Multiple containers can be added as demand grows.
Clean energy transition: Replaces diesel with zero-emission hydrogen fuel cells.
The Path Forward
Marubeni's world-first demonstration establishes proof of concept for metal hydride hydrogen transport, but significant work remains to achieve commercial scale. The one-year customs approval process highlights the regulatory groundwork needed globally before this technology can be routinely deployed.
For Japan, the trial supports national hydrogen strategy objectives while exploring new JCM business models with partner countries. For the global hydrogen economy, it adds another potential transport pathway alongside compressed gas, liquefied hydrogen, and ammonia — one that may prove particularly valuable for remote island applications and emergency energy storage.
Whether metal hydride alloy transport becomes a mainstream hydrogen logistics solution or remains a niche application depends on resolving the economic, regulatory, and technical challenges identified in this first-of-its-kind demonstration.
