The global greenhouse gas emissions from the shipping sector should be reduced by 50% by 2050 compared to 2008, according to a recent decision by the International Maritime Organization (IMO). To reach this there is a need for low-emitting alternative fuels as other measures are not enough. Thus, the shipping sector is in a stage of searching for new energy carriers that can fulfil present regulations and also be a bridge to coming, discussed or foreseen demands and regulations.

The total fuel use for shipping globally is estimated to around 300 million tons/year meaning that the replacement of all fuel oil used today with non-fossil alternatives will likely involve many different alternatives. A newly finished project within the Swedish Energy Agency and f3 collaborative research program Renewable transportation fuels and systems has had a goal to make an initial assessment of the role of renewable fuels in the global shipping sector, and to contribute with scientifically based decision support for the choice of alternative marine fuels to industry, policy makers and other stakeholders. The project, titled Prospects for renewable marine fuels, includes a synthesis of current knowledge on alternative marine fuels, an assessment of e.g technical, envi­ronmental and economic factors influencing the choice of marine fuels, and a multi-criteria analysis of selected alternative marine fuels providing a structured assess­ment of the fuels.

The project concludes that there has been an increased interest in alternative marine fuels in recent years, where a range of different options with different characteristics are discussed. Some perform better in terms of envi­ronmental performance and others in terms of economy, infrastructure, availability and volume. Performing an overall comparison is thus a complex task, confirmed by the project’s refer­ence group of shipping related stakeholders stating that the choice of marine fuels is influenced by the climate impact of the fuel, reliable supply of fuel, fuel price, safety, investment cost and acidification impact. Also, different marine fuels are better suited for different kinds of shipping, depending on the ship type, maximum power requirement, area and type of operation, operational profile and the limitations of cargo capacity.

According to the mentioned multi-criteria decision analysis, overall economic criteria are considered more important for stakeholders’ choice of marine fuels than technical, envi­ronmental and social factors. However, different stakeholder groups (ship owners, authorities, engine manufactures and fuel producers) weigh the criteria differently, resulting in different fuels turning out as the most interesting option.

At this point, a summary report is available. The multi-criteria analysis is presented in a scientific publication that will be linked as soon as it is accepted.

The project has been lead by Julia Hansson, IVL, with participants also from Chalmers.