Sustainable supply chains for maritime biofuels - Insights into the link between technology and feedstocks

This study by Platform Duurzame Biobrandstoffen in collaboration with TU Delft is a review of the most viable biofuels for the maritime sector and how their sustainable production can be ensured from an early stage of supply chain design. It is based on up-to-date literature as well as on 14 expert interviews from the fields of combustion technology, biofuel production, biofeedstock growth, sustainability and supply chains. It further introduces the concept of biohubs, first developed during a BioMobilisation (BioMob) expert session organised by the Platform Duurzame Biobrandstoffen in 2018. Finally, the report demonstrates a feedstock selection approach for the design of inclusive and sustainable biofuel supply chains.

The review of maritime biofuels concludes that there is no one-size-fits-all solution for replacing heavy fuel oil and that the choice of alternative fuel is highly contextual. Most alternative fuels will require a compromise of some sort. For instance, short-chained oxygenates (such as alcohols, ethers and esters) produce a particularly clean combustion but may not be suited for long-distance transport due to their significantly lower energy content. Furthermore, the ecological and social sustainability of a biofuel depends largely on the choice of feedstock and its underlying agricultural or forestry practices. In addition, conversion technologies are currently shifting from feedstock-specific (e.g. biochemical) towards non-specific (e.g. thermochemical) processes. Thermochemical processes are maturing fast and their products will enter the markets in the mid 2020s. This lays the foundation for a large scale lignocellulosic biomass demand.

Indicative greenhouse gas (GHG) abatement costs were calculated for the considered fuel options, underlining the aforementioned contextuality through their broad ranges. Liquefied biogas (LBG) for instance, may be the most expensive option or may contend with the cheapest fuels, dependent on the feedstock's costs and greenhouse gas savings. Generally, it can be concluded that lignin oil appears to be a particularly cheap decarbonisation option from today's understanding, but advances in technology and markets may revert this picture in the near future.

From the feedstock and sustainability expert interviews, it became evident that the environmental and social impacts of a feedstock are highly contextual and do not allow for generic conclusions. For instance, waste stream potentials are often identified from a supply chain perspective, but without considering that these waste streams often already fulfill a local function. Any framework or feedstock selection approach therefore needs to allow for contextual adjustments. Certification schemes that address sustainability criteria for biomass growth can be applied as they have already been worked out for most types of biomass. In order to better address social sustainability of biomass growth, cooperation between biofuel producers and non-governmental organisations can be an effective measure.

Lastly, a structured feedstock research approach is presented that aims to ensure environmental and social sustainability from an early stage of the supply chain design. It aims to initially scope the feedstock search by defining a region for biomass growth and a final market to sell the biofuel to, as these two aspects already shape the political context of the resulting fuel (laws, regulation, support, ambitions) and the socio-economic-environmental context of the feedstock growth region and the market. This is followed by a stakeholder analysis that identifies key stakeholders within the value chain, their roles and interest, power distribution and room for improvement. Potential value conflicts and diverging interests can be analysed and supplemented with established social indicators for quantitative assessments. A landscape analysis then gains insights into unused biomass potentials, for instance via abandoned land or non-optimally managed forests or crops. It aims to analyse the status quo of land uses and ecosystems in the region of biomass growth, as well as the current climate and pressures on biodiversity. Finally, bioenergy crops are compared against residues in terms of their greenhouse gas savings potential, their contribution to food and biodiversity, their provision of ecosystem services and their usefulness for humans or nature. To better evaluate such a multi-criteria choice in a methodological manner, an analytical hierarchy process is recommended.

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