Decarbonization of shipping: Hydrogen and fuel cells legislation in the maritime industry

The maritime industry is a significant component of the transportation sector. Ships are the major element of the maritime industry, and propulsion power comes from fossil fuels, such as heavy fuel oil or marine diesel oil. These fossil fuels are used in conventional marine diesel engines and result in high levels of harmful emissions. These emissions contribute to the greenhouse effect and global warming, which is why efforts have been made to regulate and limit them within specific boundaries through various rules and regulations. However, with current technology, it is not possible to stay within these regulations. Therefore, the maritime sector has embarked on the quest for alternative power sources, and as a result, alternative fuels and fuel cells have gained importance. Hydrogen, one of these alternative fuels, is a promising solution with a carbon-free structure for the maritime industry to move toward sustainability. However, ships are considered high-risk areas, which is why specific standards need to be established for the use of hydrogen and fuel cell technology in ships. Hydrogen bunkering, onboard storage, and power system design, limits, and operational aspects must be properly elaborated. Although there are several substantial international standards and regulations for gas, liquid, and dangerous cargo, there is a lack of specific and detailed regulations for the use of fuel cells and hydrogen fuel onboard ships. This paper reviews the relevant regulations and standards while showing the regulatory gap concerning hydrogen and fuel cells by discussing the main barriers and highlights the current and future agenda of the industry toward decarbonization vision.