Applicable Convention of the use of biofuels on ships

What conventions apply to fuels used on ships?

There are SOLAS flash point regulations, MARPOL Annex VI Regulation 4 sulfur content regulations, and MARPOL Annex VI Regulation 18.3 fuel quality regulations.

What treaty rules apply to biofuels?

MARPOL Annex VI Regulation 18.3.1 or Regulation 18.3.2 is applied according to conditions such as biofuel mixture ratio and engine modification.

What is the difference between MARPOL Annex Regulations 18.3.1 and 18.3.2?

For “fuel oil derived by petroleum refining”, regulation 18.3.1 of MARPOL Annex VI applies.

For "fuel oil derived by methods other than petroleum refining", regulation 18.3.2 of the MARPOL Annex applies.

What conditions does the above regulation apply to biofuels?

MEPC78 clarified how to apply MARPOL Annex VI Sections 18.3.1 and 18.3.2 when using biofuels, and approved a Unified Interpretation.

*The point is to confirm that the fuel oil specification shall not cause an engine to exceed the applicable NOx emission limit in MARPOL Annex VI Regulation 18.3.2.

①A fuel oil which is a blend of not more than 30% by volume of biofuel should meet the requirements of Reg. 18.3.1 of MARPOL Annex VI.

This is interpreted as "treated in the same way as petroleum-derived fuels" without the requirement that the NOx regulation value is not exceeded by using the fuel concerned" in regulation 18.3.2 of MARPOL Annex VI.

②If fuel mixed with more than 30% biofuel is used, regulation 18.3.2 of MARPOL Annex VI will be applied.

MARPOL Annex VI 18.3.2 Regulations regarding the handling of the requirement that "the NOx regulation value shall not be exceeded by using the fuel concerned" shall be dealt with in the NOx critical components in the approved technical file or in the setting/operating value in the technical file. Depending on whether or not there is a change that exceeds the stated range, an evaluation may be required to ensure that the NOx regulation value is not exceeded.

Please check the Class NK website information page for various precautions regarding the use of biofuels, including the above.

Class NK Information services link

https://www.classnk.or.jp/hp/en/info_service/bio/