MOL to begin construction of a novel green hydrogen-generating vessel in 2024

Japanese shipping major Mitsui O.S.K Lines (MOL) has designed a fully-autonomous unmanned ship concept that it describes as a "mobile hydrogen production plant."

PHOTO: Model of MOL's vessel designed as a hydrogen-producing plant. Mitsui O.S.K. Lines

Using primarily wind for ship propulsion with assistance from hydrogen fuel cells, the vessel is conceptualised to produce zero-emission hydrogen (green hydrogen) on board. This green hydrogen can then be supplied for offshore use.

According to the company’s fact sheet, the sails will generate wind energy for primary propulsion and also power underwater turbines. These turbines will help to electrolyse pure water from desalinated seawater to produce green hydrogen. Onboard, hydrogen will be stored in tanks in the form of methylcyclohexane (MCH).

MCH is a liquid organic hydrogen carrier (LOHC) made by reacting hydrogen with toluene. Chemically, MCH is a saturated hydrocarbon with a flash point of -4°C and is commonly used as a solvent.

While hydrogen is projected to be critical to decarbonising the shipping sector, it is highly flammable and has a low volumetric energy density. As a result, storage is difficult and expensive. LOHC technology can eliminate the risk of fire during large-scale fuel transportation.

In LOHC technology, hydrogen is chemically bonded to stable liquid organic carriers, which are derivatives of oil that react reversibly with hydrogen. It eliminates the need to compress hydrogen and makes transporting it safer and more cost-effective.

MOL explains that when the MCH tank reaches near capacity, the vessel’s automated sailing system will be activated. If wind power is insufficient, MCH can be dehydrogenated (chemically separating hydrogen molecules) to supply electricity to the ship's propellers for secondary propulsion.

During berthing, the excess MCH will be transported to land via a pipeline and it can be used offshore.

MOL has concluded its trial demonstration with a yacht in Omura Bay in Japan's Nagasaki Prefecture. Taking the same concept to scale, the company plans to build a large cargo ship by 2030.

By Konica Bhatt

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