Roadmap for Sustainable Fueling Options in the Maritime Sector

The maritime industry is at a crossway. Decarbonization of this sector is an essential part of efforts towards climate change mitigation. Especially the long-distance operations are challenging to decarbonize as electrification is not an option there. Therefore, more and more alternative fuels are being considered to decarbonize the shipping industry.

There are options such as PtX, biofuels, blue fuel (ammonia), and electro fuels. However, the choice of the fuel for the future requires an in-depth analysis of different costs, sustainability factors, and biomass availability. This study answers the question of the least cost fueling option given restrictions in greenhouse gas emissions (GHG) and biomass availability.

We use an open-source linear least-cost optimization model, which utilizes data on biomass availability, shipping demand, vessel expenditure, and fuel price to propose fuel transition roadmaps for the maritime industry. The necessary input  data are from the MarE-Fuel project and literature. The future fuel mix will be analyzed, including sustainable maritime fuels, which are essential to decarbonize the maritime industry in the long term.

The considered fueling options in this model are electrofuels (methanol and ammonia), biofuels (Refined Pyrolysis Oil, LBG), e-biofuel (Bio-emethanol), blue fuel, lower emission fossil fuels (LNG and VLSFO), and classical fossil fuels (HFO). The potential of these new fuels will be critically assessed by including the GHG emissions of the production process of these fuels.

This work aims to identify the main issues the industry is facing at present up until 2050 and provides an outlook on challenges and opportunities towards climate mitigation that the maritime industry might be developing in the future. We find a diversified picture of a decarbonized maritime future.

The future fuel mix is expected to be highly dependent on advancing technologies, ramping up fuel-production facilities, biomass availability, and safety advancements. In an ambitious GHG-emission reduction scenario with high biomass availability, one can see a gap between expected fuel demand and feasible fuel supply given the GHG-emission reduction constraints already from 2028 onwards.

In a low biomass availability case, this feasibility gap is even more significant. Given the efforts towards NetZero by 2050, this presents enormous challenges for the decarbonization of the maritime industry at present and for the following years to come.