On 17 March 2025 ClassNK issued an approval in principle (AiP) for a large-size ammonia-powered ammonia carrier, jointly developed by Mitsui OSK Lines, Namura Shipbuilding Co, and Mitsubishi Shipbuilding Co, to transport large volumes of ammonia with low emissions. The certification demonstrates its feasibility from regulatory and safety perspectives.
Ammonia is expected to see wider use as a zero-carbon fuel and increased demand in power plants since it does not emit CO₂ when combusted. The carrier features larger cargo tanks than very large gas carriers (VLGCs) and very large ammonia carriers (VLACs), while also enabling low-emission transport with ammonia as fuel.
In addition, it meets the restrictions on entry into major power plants in Japan, while maintaining specifications consistent with current VLGCs in terms of connections to power plants and ammonia supply terminals during loading and discharging.
ClassNK reviewed the design concept of the vessel based on ‘Part C Guidelines for Ships Using Ammonia as Fuel (Edition 3.0.2)’ of the ‘Guidelines for Ships Using Alternative Fuels’ as well as the IGC Code, and examined the risk assessment through HAZID, focusing on the safety of ammonia toxicity. Upon confirming that the prescribed requirements had been met, ClassNK issued AiP.
At the initial stage of designing or before the specific target ship to be implemented is decided, the design is examined based on the existing regulations such as international conventions and ship classification rules, and an Approval in Principle (AiP) is issued as proof of conformity with requirements.
