Biodiesel reduces up to 81% of ships’ soot emissions

The measurements with 100 percent biofuel were made during a three-day voyage on the vessel Falstria Swan from Uni-Tankers. The collected data has been analyzed and compared with baseline measurements made with conventional diesel on the same vessel. (Photo: Danish Technological Institute)

Soot particles, also known as black carbon, are among the most harmful emissions from shipping, both for the climate where they contribute to global warming and ice melting in the Arctic, and for public health through reduced air quality.

Now experts from the Cleanship project document that the use of 100 percent biodiesel (B100) in real sailing can reduce black-carbon emissions by up to 81 percent at low engine load and up to 61 percent at high engine load compared to traditional marine gasoil (MGO).

“We knew that biofuel would provide cleaner combustion, but the size of the reduction—especially at low loads—is a positive surprise,” said Simon Bastrup Spangenberg, a consultant and measurement expert in alternative fuels and emission reduction at the Danish Technological Institute. “It illustrates that biodiesel can not only reduce net CO2, but also black carbon, which is of great importance for shipping’s overall climate footprint. At the same time, the measurement technology allows us to monitor emissions in much more detail than before.”

Monitoring emissions in real time

The measurements were made on board the tanker Falstria Swan from the shipping company Uni-Tankers.

Here, an advanced, online black-carbon sensor from Green Instruments, developed in collaboration with the Danish Technological Institute, has made it possible to monitor emissions in detail and in real time during the ship’s normal operation.

For Uni-Tankers, the measurements are directly translated into new, practical knowledge.

“The new data on pure biodiesel (B100) under real operation gives us a solid basis when planning investments in green transition—both for us at Uni-Tankers and for the rest of the industry,” said Troels Reppien, the technical director at Uni-Tankers.

Although biodiesel documents a significant reduction in black carbon, global biofuel production can only cover a small part of the energy needs of the international fleet.

Therefore, the Cleanship project continues to analyze data and work on recommendations for how black carbon and other emissions can be effectively reduced in shipping.

The results of the measurement campaign have now been submitted to the International Maritime Organization in the form of a white paper.

The documentation is intended to contribute to international efforts to reduce black-carbon emissions, especially in Arctic regions where soot particles have a particularly large climate impact on ice and the environment. 

The white paper has been included for consideration at the IMO’s 13th meeting of the Sub-Committee on Pollution Prevention and Response, which will take place Feb. 9-13.

Cleanship is a Danish research project (2024-’26) led by the Danish Technological Institute in collaboration with partners Uni-Tankers A/S, Green Instruments, Mærsk Mc-Kinney Møller Center for Zero Carbon Shipping, Danish Shipping Companies and Danish Maritime.

The project aims to reduce harmful maritime emissions through testing and demonstration of biofuels, energy-saving technologies and operational optimizations.

The project is supported by the Danish Environmental Protection Agency’s MUDP program with a grant of approximately USD$2.9 million.

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