Technological solutions for boosting hydrogen role in decarbonization strategies and net-zero goals of world shipping: Challenges and perspectives

Facing the problems concerning greenhouse gas (GHG) emissions from international ocean shipping has meant that the latest regulations of the International Maritime Organization, issued on 1st January 2023, have come into force, with the aim of reducing GHG emissions from maritime activities. Hydrogen has been suggested as an alternative fuel to achieve decarbonization ambitions in the near future. Although hydrogen has been investigated and developed over the years, its application in ocean freight is still at an embryonic stage, with a very limited number of studies exploring its feasibility. Therefore, this work comprehensively reviewed the pertinent knowledge in the field, associated with the production, storage, and energy-derivation of hydrogen on ships and aims to identify the potential issues and provide possible solutions for fueling the shipping industry with hydrogen energy. It was found that the under-par development of hydrogen-based energy for the shipping industry can be explained by the following reasons: (i) the inability of space-limited ships to use the currently available hydrogen technologies; (ii) difficulties in hydrogen storage; (iii) under-developed infrastructure at hydrogen-bunkering ports; (iv) high retrofitting, maintenance, and operating costs; (v) incomplete guidelines, international rules and regulations for the implementation of hydrogen in fueling global shipping; and (vi) cheaper conventional fuels leading to the reluctancy of industry players to become involved in such a green transition. Finally, several suggestions relating to technological aspects and policy implications were given aiming at advocating the green transition of hydrogen-powered maritime industries for cleaner and more sustainable global trading.