IMO Clears Path for Greater Biofuel Use with New Guidance

The IMO has approved new guidance allowing bunker ships to carry higher biofuel blends. Image Credit: IMO

The IMO has taken a significant step toward enabling wider adoption of biofuels in shipping, following the approval of new interim guidance during the 83rd session of the Marine Environment Protection Committee (MEPC 83) held last week.

The updated guidance raises the allowable blend ratio of biofuels from 25% to 30% by volume for carriage on conventional bunker vessels.

Blends above this threshold can only be transported on IMO type 2 tankers.

This decision reflects the shipping industry's growing interest in decarbonisation pathways and follows years of trialling biofuels as either drop-in replacements or blend components alongside conventional marine fuels, FOBAS, part of Lloyd's Register, said in an emailed statement on Monday.

It argues that most marine biofuels in current use are blended at ratios between 20% and 30%.

The revision supports the IMO's broader strategy to reduce GHG emissions from shipping and opens new opportunities for both suppliers and operators to expand their use of biofuel blends.

However, regulatory challenges remain, particularly around nitrogen oxide (NOx) compliance.

Under existing MARPOL Annex VI rules, non-petroleum-derived fuels must not cause engines to exceed NOx limits, unless exempted by the vessel's flag State.

To help ease this hurdle, MEPC has also approved updated interpretations clarifying that biofuel blends of up to 30% can be treated the same as conventional fuels, without requiring additional NOx emissions testing.

For blends above 30%, NOx trials are still not needed, provided the engine's settings remain in line with its original Technical File.

Despite these developments, the new interpretations are not binding.

Shipowners are advised to seek written confirmation from their flag administration before using higher-percentage blends, FOBAS said.