Guidelines for alternative fuels further considered by IMO

A suite of guidelines for the safe design and operation of ships using alternative fuels (ammonia, hydrogen, LPG and other low flashpoint fuels) were considered further by IMO’s CCC Sub-Committee (CCC 9) held from 20 to 29 September 2023. Whilst progress was made on some aspects, and the draft LPG Guidelines finalised with a view to adoption at MSC 108 in May 2024, the draft guidelines for other alternative fuels require further work intersessionally for consideration and finalization at CCC 10 in September 2024 with a view to adoption at MSC 109 in December 2024.

Specific provisions associated with the bunkering of the alternative fuels, in respect of mitigation of the risks to the ship associated with the fuels, were considered in detail for ammonia and hydrogen. From the discussions it is clear that both present unique risks that require detailed consideration and provisions to mitigate those risks.

For ammonia it is not just the risks associated with toxicity, for example, to the extent that it may prevent the concept of safe-haven/refuge on board being applicable for certain ship types, that requires mitigation but also the corrosivity of the product and its effect on materials and so design of equipment. For storage, among the three different storage options for ammonia, i.e. refrigerated ammonia, semi-refrigerated ammonia and pressurized ammonia, only the former two should be considered for the purpose of the interim guidelines as a first stage, and that the use of pressurized ammonia systems would be possible through the alternative design process; portable tank provisions for ammonia should not be specifically developed.

For hydrogen the difficulty of containing leaks presents safety challenges and it was agreed that during bunkering operations leaks of hydrogen should be able to freely escape without accumulating to mitigate risk of fire or explosion. In this regard, as small leakages may form hydrogen pockets and coupled with hydrogen’s lower explosion limit and that it is impossible to de-energise electrical equipment in time, Emergency Shut-Down (ESD) principles have been removed from the current draft Guidelines.

Concerns were also expressed that ships using fuels such as LNG and methanol were being built with inadequate arrangements to debunker fuels (e.g. for pre dry dock preparations and emergencies (grounding, collisions)), due to a lack of related provisions in the IGF Code or Guidelines. It was decided not to include any such provisions at this time, but may be included when developing the draft interim guidelines for other alternate fuels such as hydrogen and ammonia.

A summary of progress is provided below.

Interim guidelines for the safety of ships using hydrogen as fuel

These draft guidelines have been developed further. They are goal-based and provide provisions for the arrangement, installation, control and monitoring of machinery, equipment and systems using hydrogen as fuel to minimise the risk to the ship, its crew and the environment. Additional intersessional work will be carried out with the aim to present the progress to CCC 10 (September 2024) with a view to finalization and adoption at MSC 109 in December 2024.

Interim guidelines for the safety of ships using ammonia as fuel

These draft guidelines have been developed further and provide an international standard for ships using ammonia as fuel. They are goal-based and will provide provisions for the arrangement, installation, control and monitoring of machinery, equipment and systems using ammonia as fuel to minimise the risk to the ship, its crew and the environment. Additional intersessional work will be carried out with the aim to present the progress to CCC 10 (September 2024) with a view to finalization and adoption at MSC 109 in December 2024.

Interim Guidelines for Use of LPG Cargo as Fuel

Due to the urgent industry need, CCC 9 developed these draft guidelines to provide unified specific guidance for ships using liquefied petroleum gas (LPG) cargo as fuel. Written in a goal-based manner they are expected to be agreed at MSC 108 in May 2024

Interim guidelines for the safety of ships using low flashpoint oil fuels

These guidelines are expected to provide an international standard for ships using oil-based fossil fuels, synthetic fuels and biofuels with a flashpoint between 52°C and 60°C. A Correspondence Group will continue to consider them and submit a report to CCC 10 (September 2024).