IMO removes regulatory barriers for biofuel blends

Interest in using biofuels and biofuel blends is increasing within the shipping industry. It is a ‘drop-in’ fuel so shifting to its use is relatively simple, and it can offer potential greenhouse gas (GHG) reductions, which includes carbon dioxide (CO₂).

But concerns have been raised over a potential increase in nitrogen oxide (NOx) emissions when an engine burns biofuels and blends. NOx is an air pollutant and is regulated by MARPOL Annex VI, and some parties are concerned that changing over to biofuels will impact the vessel’s compliance with the NOx Technical Code and, consequently, MARPOL Annex VI.

MARPOL Regulations

Regulation 18 of MARPOL Annex VI encompasses biofuels and blends, stating: “fuel oil for combustion purposes derived by methods other than petroleum refining shall not… [.2.2] cause an engine to exceed the applicable NOx emission limit…”

Up until now, proving that changing to a biofuel did not exceed NOx emission limits was onerous, typically requiring the testing of onboard emissions and fuel-specific validation testing, or requesting an exemption from Flag State.

Unified Interpretation

A new Unified interpretation (UI), approved by the IMO’s Marine Environment Committee in June 2022, removes this barrier. Now, blends that contain up to 30% biofuel (B30) will be treated the same way as fossil fuel oils – no NOx emission assessment is required and there is no need to seek an exemption from Flag State.

Furthermore, B30 to B100 biofuels are now allowed to be used without further NOx assessment in engines certified in accordance with Regulation 13 (Nitrogen Oxides) of MARPOL Annex VI, on the condition that there are no changes to NOx critical components or settings/ operating values set out in the engine’s approved Technical File.

Lloyd’s Register has conducted trials on vessels using biofuels. They found that no changes to engine settings were needed to operate on biofuels, including B100. They also report that NOx emissions were not significantly higher than comparable fossil fuels.

The UI will be issued as MEPC.1/Circ.795/Rev.6 and is already in effect at the time of writing.

Find out more

For more information on using biofuels and blends and decarbonisation guidance in shipping please see links to North’s Biofuel and blend articles and Navigating Decarbonisation website.

Our Decarbonisation Journey – d’Amico International Shipping

Article: Getting to know biofuels and blends

Article: Biofuels enter the sustainable fuel mix

Expertise Area: Navigating Decarbonisation