Integration of a tank storage solution for alternative fuels on a RoRo ship

Abstract

In order to achieve the International Maritime Organization’s vision of 50 % carbon emission reduction by 2050, it is crucial to push forward the decarbonization of ships. This goal can be reached only using carbon-free/carbon-neutral fuels such as liquified natural gas, hydrogen, ammonia and methanol. The energy transition is not exclusive to newbuilt ships but shall include the ones in service. A transition onboard a RoRo ship running on heavy fuel is investigated in this context. A multi-criteria evaluation based on several environmental, technical and economic factors is used to select the best alternative fuel. Methanol and ammonia are the most promising. The integration onboard of these fuel solutions starts by determining storage tank locations while respecting the structural limitations of the ship’s structure, in addition to the required equipment and systems adapted for fuel handling. The viability of methanol and ammonia is studied by determining the impact of the retrofitting process on the ship’s carrying capacity and operating range. Moreover, the amount of CO2 emissions related to each fuel from well to wake is quantified. Altogether, the economic viability of the fuel solutions is determined by calculating the total cost of ownership.