Feasibility of retrofitting Ro-Pax ferries to utilise hydrogen propulsion and storage technology

Pressure to reduce greenhouse gas emissions is increasing across the global maritime sector, with major changes required across nearly all vessel types. Adoption of alternative fuels, such as hydrogen, will be vital to achieving decarbonisation, however, for operators, transition pathways to hydrogen adoption across their fleets are still subject to uncertainties, such as the competitiveness against other emerging fuel options, potential fuel cost reduction trajectories, time-to-maturity of key technologies and development of the required infrastructure. This study explores some of these uncertainties with techno-economic modelling and concept-level engineering of a real conversion case. Three different retrofit alternatives are explored, the first option utilises compressed hydrogen storage with dual-fuel engines, while the other two make use of 100% hydrogen-powered propulsion systems (fuel cells and internal combustion engines), coupled with liquid hydrogen storage. A Total Cost of Ownership (TCO) model is created to assess the cost of conversion for the options presented, considering the fuel OPEX of blue and green hydrogen and retrofit CAPEX of each technology, presenting a comparison with the conventional diesel-powered baseline vessel. Finally, a sensitivity analysis is performed, exploring the impact of government subsidies and locational factors (e.g., hydrogen transport distances).