Handling of the use of biofuels on ships
Biofuels are renewable fuels produced from biological organisms (biomass) in which the primary raw materials used are vegetable oils. Biofuels do not emit sulphur oxides (SOx) during combustion; moreover, they are generally considered to be carbon neutral because the amount of carbon dioxide (CO2) they do emit during combustion tends to be absorbed by source plants, etc. during their growing stage. In addition, biofuel usage can also be advantageous when used as a drop-in marine fuel (depending on fuel type) because modifications of existing marine diesel engines converted over to biofuel use are typically not required.
For these reasons, the number of biofuel trials being held has been increasing in recent years; this, in turn, has led to a corresponding increase in the number of inquiries received related to biofuel usage. Since these inquiries tend to be about various matters and not just general information requests, we have prepared the following questions and answers for your reference in order to better support safe and proper operation when using biofuels on ships.
For better understanding of the use of biofuels on ships
|What type of biofuels are usually used?
For marine use, currently main candidate biofuels are of the following three types.
|Are there any IMO statutory requirements regarding CO2 emission accounting when using biofuels?
Biofuels do emit CO2 when burned, but they are, for the most part, considered to actually generate zero CO2 emissions (i.e. they are carbon neutral) because the CO2 that is released into the atmosphere is eventually absorbed by plants, etc. during their growing stage . However, regarding the consideration of the GHG emission reduction effect (conversion factor in IMO EEDI and EEXI as well as emission factor in IMO DCS and CII) from ships using biofuels, a procedure for evaluating the CO2 reduction effect of biofuel in life cycle accounting is currently being developed by the IMO, Interim Guidance (MEPC.1/Circ905) was approved on the use of biofuels under IMO DCS and CII. For details on the interim guidance, please refer to Technical Information TEC-1307.We will provide updates on IMO progress in developing this procedure as such information becomes available to us.
|What IMO statutory requirements may be applicable to the use of biofuels?
Use of biofuels can be subject to requirements for quality of fuel oils of Reg. 18.3 of MARPOL Annex VI in addition to requirements applicable to conventional petroleum-based fuel oils (e.g. flash point requirements of SOLAS, sulphur content requirements of Reg. 14, MARPOL Annex VI, etc.).
|What biofuels does Reg. 184.108.40.206 “fuel oil...shall not cause an engine to exceed the applicable NOx emission limit...” apply to?
With regard to the use of biofuels, Unified Interpretation (UI), which clarifies the application of Reg. 18.3.1 and 18.3.2 of MARPOL Annex VI, is approved at MEPC 78. Also, amendments to the UI, which add a synthetic fuel to the applicable scope, are approved at MEPC79. The outline of UI (MEPC.1/Circ.795/Rev.7 paragraph 13) is as below.
1. A fuel oil which is a blend of not more than 30% by volume of biofuel or synthetic fuel should meet the requirements of Reg. 18.3.1 of MARPOL Annex VI. (i.e. Such a fuel oil is not be subject to the Reg. 220.127.116.11 “fuel oil...shall not cause an engine to exceed the applicable NOx emission limit...”.)
2. A fuel oil which is a blend of more than 30% by volume of biofuel or synthetic fuel should meet the requirements of Reg. 18.3.2 of MARPOL Annex VI. For application of the Reg. 18.104.22.168 “fuel oil...shall not cause an engine to exceed the applicable NOx emission limit...”, it should be interpreted that:
(i) Where a marine diesel engine can operate on a biofuel or a synthetic fuel, or blends containing these fuels without changes to its NOx critical components or settings/operating values outside those as given by that engine’s approved Technical File, such a fuel oil should be permitted to use without having to undertake the assessment as given by the Reg. 22.214.171.124.
(ii) Where a marine diesel engine can operate on a biofuel or a synthetic fuel, or blends containing these fuels with changes to its NOx critical components or settings/operating values outside those as given by that engine’s approved Technical File, such a fuel oil shall be required to undertake the assessment as given by the Reg. 126.96.36.199. For the assessment, onboard simplified measurement method according to 6.3 of the NTC 2008 is available. Also, as applicable to possible deviations when undertaking measurements on board, an allowance of 10% of the applicable limit may be accepted.
|What biofuels and synthetic fuels does the UI above-mentioned on No.4 apply to?
1. A biofuel is a fuel oil which is derived from biomass and hence includes, but is not limited to:
(i) Processed used cooking oils;
(ii) FAME (Fatty Acid Methyl Esters);
(iii) FAEE (Fatty Acid Ethyl Esters);
(iv) SVO (Straight Vegetable Oils);
(v) HVO (Hydrotreated Vegetable Oils);
(vi) BTL (Glycerol or other biomass to liquid type products).
2. A synthetic fuel is a fuel oil from synthetic or renewable sources similar in composition to petroleum distillate fuels.
|What precautions should be taken when using biofuels?
FAME is a fuel in which various issues may arise over time; so, it is important to take appropriate countermeasures and use the biofuel up as soon as possible.
|What are the recommendations for using biofuels?
Prior to using biofuels, it is recommended to consult with the engine and fuel supply system manufacturer about the suitability of biofuel and the necessity of modifications/adjustments for equipment.
For any questions about biofuels, please contact:NIPPON KAIJI KYOKAI (ClassNK)
Machinery Department, Administration Center Annex, Head Office
Address: 3-3 Kioi-cho, Chiyoda-ku, Tokyo 102-0094, Japan