Emerging ship design principles for ammonia-fueled vessels

This publication builds on findings from previous MMMCZCS studies to present a comprehensive guide to the emerging solutions for ammonia-fueled vessels from a ship design perspective. The publication addresses oceangoing container ships, bulk carriers, and tankers, and does not consider coastal vessels and passenger ships.

Safety concerns are a major challenge for the adoption of ammonia as a marine fuel. A recent study provides advanced safety knowledge and understanding of ammonia handling and storage on board.¹ Our analysis further highlights the importance of several key design and operational factors that can improve safety on board ammonia-fueled vessels, such as the choice of ammonia fuel storage system, secondary containment mechanisms, ventilation, rapid and reliable sensors and alarms for ammonia leaks, and rapid and reliable shutdown of the fuel system.

Considering the shift toward dual-fuel propulsion in ship designs, there will be a need to create not only the correct equipment and control systems, but also new or revised procedures, work processes, and maintenance regimes. Within the Human Factors Considerations: Ammonia Fuel End-of-Stage Report, the MMMCZCS has provided a preliminary account of the human factors that should be addressed to prepare for the use of ammonia as a marine fuel.² The results point to the need for companies and the marine industry to apply human factors engineering principles, such as ergonomics, within the design of ammonia-fueled vessels to reduce potential crew exposure to ammonia.

The aim of this document is to help shipyards, ship designers, and operators/owners navigate through main decisions when developing new ammonia-fueled ship designs. Figure 1 presents the overall design flow leading to an ammonia-fueled vessel. The figure highlights the areas of ship integration and safety assessment that form the focus of this document.

Although many of the design aspects relevant to ammonia are already known from gaseous and low-flashpoint fuels, this document covers the ammonia liquid gas storage, handling, and safety aspects. This is to ensure that the readers who are not acquainted with alternative fuels such as methane can obtain a basic understanding of the design of gaseous fuel systems.

The document opens with a review of the key properties of ammonia (Section 2) and the key design aspects of ammonia-fueled vessels, including some example vessel designs (Section 3). This is followed by five main sections designed to enable easy access for readers to the sections of interest, as follows:

– Tools to assess ammonia safety during the design phase (Section 4)
– Safety considerations (Section 5)
– Regulatory outlook (Section 6)
– Ammonia ship technology systems (Section 7)
– Vessel design options with key considerations for ammonia fuel systems (Section 8)

Finally, the conclusion (Section 9) briefly summarizes the overall key messages of the document, and extensive further background and analytical details are supplied in two appendices: Appendix A focuses on a regulatory gap analysis that supplements Section 6, while Appendix B elaborates with comprehensive descriptions of the technology on board and the pertinent design practices.

Disclaimer

This publication has been prepared by Fonden Mærsk Mc-Kinney Møller Center for Zero Carbon Shipping (“Center”) for informational purposes only. The content herein is based on studies, research, and analyses conducted by the Center, as well as publicly available information as of the date of publication. While the Center has made every effort to ensure the accuracy and reliability of the information presented, it does not guarantee or warrant, either expressly or impliedly, the completeness, accuracy, or suitability of this information for any specific purpose.

This publication is not intended to serve as technical, regulatory, legal or other advice. Readers are encouraged to consult with their advisors before making any decisions or taking actions based on the information contained herein. Compliance with applicable laws, regulations, and standards, including but not limited to those related to safety, environmental protection, and design requirements, remains the sole responsibility of the reader.

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