Assessment of a Mediterranean Hydrogen Generation Hub powered by Offshore Floating Wind for the Decarbonization of the Maritime Shipping Sector

Nowadays around 80-90% of global trade is performed via maritime shipping and as indicated by the International Maritime Organization, by 2050 this number could increase up to 115% with respect to 2020 levels. The shipping sector is responsible for around 3% of the annual global greenhouse gas emissions on a carbon dioxide equivalent basis and approximately 13% and 12% of the annual global nitrogen oxides and sulfur oxides emissions, respectively. Considering that about 99% of the energy demanded by the international shipping industry is met by fossil fuels, the utilization of alternative fuels is needed to mitigate the CO2 and GHG emissions. Among the alternative fuels, hydrogen can be used in fuel cells, as a fuel mixture with traditional fuels and as a substitute in combustion processes. In maritime application, it can be stored on board as compressed gas, liquid, or chemically bounded. The storage of compressed gaseous hydrogen require enormous volumes for long-range routes, due to its low volumetric density. The volumetric density of liquid hydrogen is instead 71 times higher than that of the gaseous form. Therefore, in maritime shipping one alternative could be to store this fuel in the cryogenic liquid phase. In this master thesis, the assessment of a hydrogen generation hub for ship refueling powered by offshore floating wind in the Mediterranean Sea has been performed. The ship refueling is intended to be performed directly on the sea. The Mediterranean Sea has been selected in this work because it is one of the most busiest shipping areas of the World, accounting for around 15% of the global shipping activity. First of all, the most suitable plant location in the Mediterranean Sea has been evaluated considering different constraints as vessel route density, bathymetry, wind resource, distance from coast, geological context, habitats preservation and maritime boundaries. The annual hourly liquid hydrogen production for the specific plant location has been then calculated, considering a floating offshore wind farm of 300 MW of rated capacity located in the Strait of Sicily. The wind farm power output has been calculated through the use of the WAsP software, while the hourly wind farm production and the hourly liquid hydrogen production have been calculated through the use of Matlab. Moreover a techno-economic analysis has been performed considering different scenarios.