Life-cycle cost assessment of alternative marine fuels to reduce the carbon footprint in short-sea shipping: A case study of Croatia

The reduction of emissions generated by internal combustion engines represents one of the most important research topics in the marine sector. This especially refers to carbon dioxide (CO2) which is a major greenhouse gas. This paper deals with the viability of alternative fuels to reduce CO2 emissions in the Croatian short-sea shipping sector over a ship lifetime. The aim of the study is to identify appropriate alternatives to diesel-powered options, taking account of environmental and economic criteria. Besides diesel, which is currently the main marine fuel in Croatia, an analysis was conducted of electricity, methanol, dimethyl ether, natural gas, hydrogen and biodiesel, and the results are illustrated on three different Croatian ro-ro passenger ships, operating on short, moderate and relatively long routes, respectively. Life-Cycle Assessment (LCA) indicated the most environmentally friendly power system configuration with alternative fuel. The investigation from an economical point of view was performed by Life-Cycle Cost Assessment (LCCA) which also considered potential carbon allowance scenarios. The results highlighted an electricity-powered ship as the most ecological as well as the most cost-effective option among those that are investigated, taking account of the real Croatian electricity mix that includes 46% of renewable sources.