Holistic energy efficiency and environmental friendliness analysis of inland ships with alternative power systems

In order to deal with the decarbonisation of the transport sector, many policies suggest the application of alternative fuels with an emphasis on the electrification, an increase in the energy efficiency of transportation modes and a shift of freight and passenger transport from road transportation to other modes of land transport such as inland waterway transport. The vessels engaged in the inland waterway transport are often outdated, powered by low-energy efficient diesel engines, operating near populated areas and thus directly impair the air quality of the nearby population. Therefore, their energy efficiency and environmental friendliness need to be improved. Furthermore, energy efficiency and environmental friendliness assessment of ships with alternative power systems represent a special issue, since such mathematical models regularly consider power systems that use fuel with carbon content only. In this paper, the retrofitting of different types of vessels (cargo ship and passenger ship) with alternative power systems (powered by electricity, methanol, natural gas hydrogen and ammonia) is considered, while the diesel power system configuration represents a baseline scenario. Their energy efficiency and environmental friendlies are assessed, considering their annual life-cycle emissions and benefit to the society, by means of the mathematical model recently published in the literature and applied to short- sea vessels only. Its applicability to other transportation modes/ship types is confirmed and differences in energy efficiency and environmental friendliness of different power system alternatives are outlined.