Ανάλυση κύκλου ζωής υγρών βιοκαυσίμων με εφαρμογή στην ναυτιλία
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Keywords
Life Cycle Assessment (LCA) ; Marine biofuels ; Maritime decarbonization ; Shipping emissions ; Sustainable shipping ; Alternative marine fuels ; Well-to-wake analysis ; Hydrotreated Vegetable Oil (HVO)Abstract
This thesis examines, through a literature review, the Life Cycle Assessment (LCA) of liquid biofuels for maritime applications, aiming to understand the factors that determine their environmental footprint and their comparability with conventional marine fuels. The study begins with an overview of the shipping sector’s energy profile and the main pollutants associated with the use of heavy fuel oil (HFO) and marine distillates, highlighting the need for assessment beyond the combustion stage through well-to-wake and well-to-propeller approaches. In addition, the fundamental methodological choices of LCA are presented, including goal and scope definition, functional unit, system boundaries, impact categories, and the critical assumptions related to co-product allocation and data quality.
Subsequently, the thesis analyzes the main production pathways of liquid biofuels for maritime use, with particular emphasis on Fatty Acid Methyl Esters (FAME) and hydroprocessed fuels such as HVO/HEFA (Hydroprocessed Esters and Fatty Acids), which demonstrate high technical compatibility as drop-in fuels. At the same time, the role of fuels such as biomethane and biomethanol is examined within the broader framework of alternative marine fuels.
The synthesis of the literature indicates that LCA results exhibit significant variability, primarily due to differences in feedstock type, production energy mix, logistics, and allocation choices. Furthermore, hotspots are identified along the value chain, namely stages associated with disproportionately high environmental burdens, such as feedstock production or fuel conversion processes. Finally, issues related to scalability, fuel quality, certification schemes, and implementation risks are discussed, leading to the conclusion that liquid biofuels can make a substantial contribution to the decarbonization of shipping, provided that sustainable sourcing practices and consistent methodological assessment are ensured.