IMO Regulatory Update - A Boost for Biofuels!

Chemical tanker ship - on deck - low res

Biofuels can play an important part in helping to lower carbon intensity for shipping. However, MARPOL Annex VI’s rules on bunker emissions which apply also to biofuels and biofuel blends, impose a challenge to the wider use of biofuels. Apart from limits on sulphur content, Regulation also requires that such fuels shall not “… cause an engine to exceed the applicable NOx emission limit…”. Whilst it is not a challenge for biofuels to meet applicable sulphur limits, it has been more challenging to demonstrate that biofuels do not cause engines to exceed the applicable NOx emission limit.

A new “Unified Interpretation (UI)” on the application of Regulation 18.3 MARPOL Annex VI in relation to biofuels was approved by the IMO’s MEPC in June 2022. According to the International Bunker Industry Association (IBIA), the UI means that biofuel blends up to 30% (B30) will be regarded in the same way as regular oil-based fuels. The UI also allows the use of B30 to B100 biofuels for “engines certified in accordance with regulation 13 of MARPOL Annex VI which can operate on a biofuel or a biofuel blend without changes to its NOx critical components or settings/operating values outside those as given by that engine’s approved Technical File”. 

The UI has been issued as MEPC.1/Circ.795/Rev.6, replacing MEPC.1/Circ.795/Rev.5.

Members are directed to the UK P&I Club's webinar: UK P&I Club Live Webinar (Series 14): Biofuels - Benefits and Barriers (, and Q&A Biofuel: Benefits and Barriers webinar - Q&A ( for additional information on this subject. 

Members are directed to Unni Einemo's article on IBIA's website for additional details. 

Jacqueline Tan

Legal Services Manager