Study on biodiesel-bunker fuel blends as marine pollutants
Among the alternative fuels currently being deployed, biodiesel blends based on Fatty Acid Methyl Esters (FAME) and Hydrotreated Vegetable Oil (HVO) represent a near-term, “drop-in” solution compatible with existing marine engines and infrastructure. Blends such as B20, B30 and B50, used with Marine Gas Oil (MGO) or Very Low Sulphur Fuel Oil (VLSFO), enable emissions reductions without requiring major technical modifications. However, their behaviour as marine pollutants and the suitability of existing response measures in the event of accidental spills are not yet comprehensively documented.
This lack of documentation introduces uncertainty for authorities, operators, and responders, and highlights the need for a structured, evidence-based assessment. Conducted jointly by the World Maritime University (WMU) and Cedre, this study is the first under the EMSA framework contract and aims to support the maritime sector by strengthening spill contingency planning, preparedness, and response as the transition to alternative fuels accelerates.
The study was structured around four main activities (Tasks), covering the full chain from fuel properties and hazards to regulatory frameworks and operational response. Together, these activities provide a comprehensive assessment of biodiesel blends as marine pollutants and identify practical, proportionate adaptations needed within existing response systems.
The first report discusses:
Task 1 – Current knowledge on alternative marine fuels: properties, hazards, and behaviour
Task 2 – Regulatory review and gap analysis
Task 3 – Response measures, technology, and equipment analysis
Task 4 – Conclusions, best practices, and recommendations
Overall, this study provides clear reassurance that the transition towards biodiesel blends as marine fuels can be supported by existing oil spill response frameworks, without the need for fundamentally new response systems. By optimising current technologies, adapting operational practices, and addressing identified regulatory gaps, authorities and operators can manage accidental releases effectively and proportionately.
By integrating scientific evidence, regulatory analysis, stakeholder input, and practical recovery testing, this report delivers a comprehensive and actionable reference for authorities, operators, and responders. It supports informed decision-making at both operational and policy levels and provides a clear pathway for safely managing accidental releases of biodiesel blends while facilitating the maritime sector’s transition towards alternative fuels.
This report is available and well worth detailed study at: