H2 – By the book

H2 – by the book is a project that aims to analyze and clarify the steps included in the alternative design process for hydrogen-powered ships, according to MSC.1/Circ.1455 Guidelines for the approval of alternatives and equivalents as provided for in various IMO instruments .

The project has been based on a real ship design that is under development, the Beluga 24, which is a high-speed passenger ship planned to be equipped with fuel cells and compressed hydrogen as fuel. The ship is covered by EU Directive 2009/45/EC on safety regulations and safety standards for passenger ships, which has been incorporated into Swedish law through the Swedish Transport Agency's regulations (TSFS 2019:120) on passenger ships on domestic voyages. In the absence of specific rules for hydrogen, a fuel with a low flash point, the functional requirements found in the IGF code become dimensioning. However, interim guidelines for hydrogen are in the process of being drawn up within the IMO.

The project has carried out the following activities:

Analysis of applicable rules and requirements.
Basic risk analysis (HAZID, workshop 1) for the hydrogen installation on Beluga 24
Technology categorization of hydrogen storage, bunkering and fuel cells according to MSC.1/Circ.1455 (workshop 2).
Gap analysis of selected functional requirements from the IGF code (workshop 2).
Further analysis of "medium" and "high" risk scenarios (workshop 2).

The project discusses the status of existing and upcoming regulations and guidelines for hydrogen-based ships, as well as how the design process for other ship types would differ. The conclusions are that the process for alternative design is complex and resource-intensive, but that at the same time it should not come as a surprise that goal- and function-based regulations are difficult to meet when there are no prescriptive rules to follow. A critical part of the work is to establish acceptance criteria that correspond a conventional design. At the same time, there is rapid development of prescriptive rules for hydrogen that will facilitate the design process going forward.

The project also suggests some areas for further research, such as standardization of assessment criteria in the initial risk analyses, assessment of hydrogen emissions via vent mast, certification and approval of vessels covered by TSFS 2017:26 and development of final design. In addition to this report, a Quick Guide has been produced to clarify the key steps in the alternative design process.