Mitsubishi Shipbuilding Develops Basic Design for Large-Scale Ammonia Carrier

Mitsubishi Shipbuilding, Mitsui O.S.K. Lines, and Namura Shipbuilding developed a large-scale, ammonia-fired ammonia carrier and obtained approval in principle (AiP) from Nippon Kaiji Kyokai (ClassNK). Prior to approval, ClassNK evaluated basic design drawings and performed a hazard identification study, both of which exceeded the detail necessary for typical AIPs.

The vessel will be bigger than modern very large gas carrier/very large ammonia carrier (VLGC/VLAC) models, improving marine transport efficiency. Its ammonia engine is intended to minimize greenhouse gas emissions. This ship design also satisfies Japan’s port entry restrictions at major power plants and ensures compatibility between ammonia loading/unloading terminals and cargo handling connections equivalent to current VLGCs.

Very large ammonia carrier; image credit: MOL Group

In late August 2024, Mitsubishi Shipbuilding, Imabari Shipbuilding, Japan Marine United Corp. and Nihon Shipyard formed a joint study with a collection of shipping companies, including “K” Line, NYK Line, and MOL, to establish standard specifications and designs for liquefied CO₂ (LCO₂) carriers. The joint study also enables LCO₂ carrier construction at additional shipyards in Japan.

The consortium will collaborate with industry stakeholders and shipyards, advancing Japanese decarbonization and construction supply chains by developing low-emission ships using low-carbon fuels, such as ammonia. The demand for LCO₂ carriers is expected to grow alongside CCS projects that transport CO₂ to storage sites by sea. Considering this market trend, the construction and supply of LCO₂ carriers will strengthen the CCS value chain and improve economic efficiency.

On January 1, 2025, a joint venture between Mitsubishi Heavy Industries (MHI) and Imabari Shipbuilding—MI LNG Co.—was renamed to MILES Co. The acronym stands for “Marine-design Initiative for Leading Edge Solution”. MILES will start designing and developing LCO₂ carriers to meet growing demand and create functional designs for alternatively fueled commercial ships.

MILES originally designed and sold LNG carriers but, in July 2023, it signed an agreement with Nihon Shipyard to perform design work for commercial ships besides LNG carriers. This consortium started joint studies to set standard specifications and designs for LCO₂ carriers. In the wake of decarbonization initiatives in the maritime transportation sector, demand is increasing for low-carbon, LNG-fueled ships. The demand for ammonia- and methanol-powered vessels is growing as well.

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In February 2025, Mitsubishi Power successfully delivered its hydrogen-ready M701 JAC gas turbine to Aluminum Bahrain’s (Alba) Power Station 5 Block 4 combined-cycle power plant, completing the project one month ahead of schedule. The company also signed a long-term service agreement to ensure the gas turbine’s availability, reliability, and performance, allowing Alba to leverage uninterrupted power generation for aluminum production and domestic industrial growth.

Also in February, the National Office of Electricity and Drinking Water (ONEE) awarded Mitsubishi Power a contract to supply two M701 JAC gas turbines and auxiliary equipment for its Al Wahda Open-Cycle Power Plant in Ouazzane, Morocco. The company also signed a long-term service agreement with ONEE for parts provision, repairs, and services, reinforcing the equipment’s high availability and reliability. The plant is expected to begin operation in 2027.