THE ENERGY SYSTEMS ANALYSIS WITH A MULTI-CRITERIA DESIGN TOOL TO DECARBONIZE MARITIME TRANSPORT

It is estimated that today maritime transport is responsible for approximately 3% of sulphur oxides (SOx), 15% of nitrogen oxides (NOx), and 2.5% of carbon dioxide (CO2) globally emitted per year and, if no measures are taken, these numbers are going to increase significantly in the next years.In this context, the phase-out of conventional marine gas oil (MGO) engines represents a crucial measure to reduce the environmental impact of maritime transportation.As the interest in low-carbon innovative technologies is growing fast and many alternatives are possible, it is important to have tools and decision instruments to compare all the possible solutions for energy production and storage on board also considering the constraints related to the vessel type.This paper aims to present an innovative multi-criteria tool for the comparison of alternative and conventional on-board energy systems for maritime vessels, both for hotel and propulsion loads, depending on the mission taken into account.The tool, developed in MATLAB environment and named HELM (Helper for Energy Layouts in Maritime applications), includes an extended and up-to-date market database for many technologies in terms of power units (i.e.engines, fuel cells) and fuel (H2, NH3, CH4, CH3OH) storage systems, resumed in a wide range of maps that correlate costs, volumes, weights, emissions and fuel environmental hazards with the installed power and the operational hours, given by the user as input.The navigation route, the vessel typology, and its dimensions are also considered in the analysis to better identify the case study and the constraints.In this work, two different vessel typologies and applications are analysed to investigate the applicability of alternative fuels in maritime transportation: i) a passenger ferry and ii) a large container ship.For both cases, a sensitivity analysis of fuel market prices and taxes on CO2 emissions is carried out to consider their impact on the economic sustainability of different solutions.It is worth noting that the multi-criteria analysis carried out has a general approach, allowing to give preliminary information on the energy system, in order to respect new requirements (e.g.more and more stringent normative in terms of pollutant emissions in ports and restricted areas).Furthermore, the HELM database can be easily extended to other power generators and storage technologies, as well as to different types of vessels.