MARPOL Annex VI - Fuel Quality Requirements

April 2006

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Earlier Steamship Mutual website articles have given details of the Air Pollution regulations brought into force under MARPOL Annex VI and of the INTERTANKO clauses prepared to assist owners and charterers to comply with the regulations and similar European regulations.

Regulation 18 of Annex VI refers to the fuel oil quality supplied by Charterers. The requirements are more or less identical to the general fuel specification requirements of ISO 8217.

Clarifications of the requirements of Regulation 18 are found in Resolution MEPC 96 (47) "Guidelines for the sampling of fuel for determination of compliance with Annex VI of MARPOL 73/78". It is expected that the guidelines will be used by Port State Control authorities as the standard for determining compliance. Useful guidance is also given INTERTANKO's "A Guide to Bunkering of Ships for the purposes of Annex VI to MARPOL" (The Guide can be obtained from the INTERTANKO online bookshop)

The Bunker Delivery Note (BDN) must record any fuel oil delivered onboard for combustion purposes. A BDN shall be presented for every barge delivery and every grade of fuel. The Sulphur content (%m/m) must be specified. A declaration should be signed and certified by the fuel suppliers' representative, to the effect that the fuel is in conformity with Regulations 14 and 18.

Resolution MEPC 96 (47) recommends that the seal number of the associated MARPOL Annex VI fuel sample is included in the BDN for cross reference purposes and that the volume of the sample bottle should be no less than 400 ml, due to a potential need for repetitive testing, INTERTANKO recommends that the sample volume is not to be less than 750ml. It should be noted by Charterers that the practical purpose of this sample, is to enable port states to verify the sulphur content of the fuel, as well as to verify that the fuel oil quality is in accordance with Regulation 18.

The Annex VI fuel sample is not primarily to be used for commercial purposes. Vessels participating in a fuel oil quality testing scheme, e.g. DNV Petroleum Services, the Annex VI sample should be considered as the 4th sample (in addition to the sample sent to the laboratory for testing, the suppliers sample, and the retained onboard sample). Keeping an Annex VI sample onboard in case of Port State Control inspections is good practice.

To satisfy Regulation 18 the Annex VI fuel oil sample should be taken by continuous drip and at the receiving ship's bunker manifold. Analysis of the onboard Annex VI sample would normally be carried if an incident occurred with the vessel following bunkering which could possibly be related to the bunker quality.

Class Surveyors, Port State Control inspectors and the agents of other interested parties will scrutinise onboard documentation and records (e.g. sampling procedures, fuel change-over procedures, Engine Log Books, BDN's etc) as well as the fuel oil sample inventory.

It should be noted that the limitations in sulphur content applies to all fuel oils (heavy fuel oils, marine diesel oils and marine gas oils) and regardless of their use onboard i.e. in combustion engines, boilers, gas turbines etc.

Currently the average sulphur content in Heavy Fuel Oils (HFO) is in the region of 2.7%. General indications from fuel testing data shows that only 0.2% of the fuel tested had a sulphur content exceeding the required 4.5%. However, tests also indicate that only 4% of the fuel oils supplied today have a sulphur content of 1.5% or less. It has been estimated that demand for the low sulphur fuel oil in the SOx Emmission Control Area's (SECAs - see below) will be in the region of 14-20 million tons per year, of which approximately only 0.7 million tons per year is available in North Western Europe today.

It is generally acknowledged that the requirements of the Annex VI will lead to increased prices for low sulphur fuels. It is uncertain at this stage whether low sulphur (1.5%) supply will be sufficient to meet demand. Low sulphur fuels are, in general, only available to suppliers with contract agreements with Oil Majors. Future spot availability is thus dependent on the market demand and price after entry into force of the Baltic Sea SECA in May 2006 and the North Sea and English Channel SECA in August -November 2007 (see below).

Low sulphur fuels may lead to additional quality problems such as instability, incompatibility, ignition and combustion difficulties and an increase in catalytic fines.

When a vessel is approaching a SECA, the fuel must be changed over to the 1.5% sulphur content fuel oils, with all original fuel being used/consumed, before the vessel actually enters the area. For ships with standard fuel oil systems consisting of one settling tank and one service tank, this will involve the filling of settling tanks with low sulphur fuel oil, adequate purification and subsequent filling of the service tank, as well as the flushing of all fuel service piping systems of high sulphur fuel, before entry into the area.

In order to simplify the operational processes, some Owners are already planning to install an additional set of fuel oil settling and service tanks for onboard separation of the dual fuel requirements and to simplify onboard fuel management. There is also an issue of whether to allocate or convert existing fuel oil tanks to tanks for the storage of marine gas oil. In any event, the conversion of additional and separate storage tanks to accommodate the low sulphur fuel, or the increased use of marine gas oil, will result in an escalation in fuel operating costs onboard.

There is increasing pressure on Charterers to utilise "modern" tonnage in order to comply not only with the SOx requirements but also the other Annex VI requirement in respect of low NOx emissions. Vessels with older machinery may find difficulties in complying with the NOx emission requirements, the NOx influencing components including injection timing/systems, combustion chamber conditions, compression in cylinders and turbocharger system efficiency. Ships in service are predominantly designed for HFO operation only with a relatively small tank capacity for marine gas oil.

A vessel's capability to segregate the dual fuels in use and provide proper dual fuel management/piping arrangements, will be factors which will influence a Charterer's decision as to which vessels to charter in the future.

Inadequate supplies of low sulphur fuel oils will mean Charterers to will need to bunker more frequently which would have significant effects on the vessel's daily operating costs. It would also have a pronounced effect of the cargo carrying capacity the vessel could uplift, plus port call delays and associated charges.

From an engineer's perspective, experience with 2 stroke engines has shown that long term operation on low sulphur fuels and the use of high base number cylinder oils may lead to abnormal build up on piston crowns, piston ring grooves and cylinder liner scuffing. Low sulphur fuels will require lower based cylinder oils to avoid such operational problems. The lower based lube oils should provide the operator with a reduction in lube oil costs. However, the need for two different cylinder oil base types to equate with the dual fuel specifications, with high and low sulphur levels presents further problems with segregated storage requirements and, possibly, capacity onboard.

The maximum operational time for the main engine to use fuel oils with low sulphur content and high base value lube oils appear to vary depending upon engine type and power output load profile. The relevant engine manufacturer and cylinder oil suppliers should be consulted prior to operation on low sulphur fuels, in order to avoid over based cylinder lube oils causing problems by over neutralisation of the acids formed from the combustion process, resulting in deposit generating calcium compounds forming on the piston crowns, piston rings and cylinder head valves.

In summary, Owners, Operators and Charterers will need to ensure that their bunker specifications, fuel supply agreements, and charterparties all take the new requirements into account. In addition, the possible impact of inadequate supplies of low sulphur fuel on operational costs will also need to be considered. For vessels operating in the SECAs, fuel change over procedures, fuel specification charts and associated documentation will additionally be required.


Important Dates: 

19 May 06 Baltic SECA enters into force (MARPOL Annex VI and EU directive 1999/32/EC). 

11 Aug 06 Maximum sulphur content of bunker fuel for passenger ships to/from EU ports - 1.5% (EU directive). 

11 Aug 07 North Sea and English Channel SECA enters into force under EU Directive while the IMO date is 22 Nov 07. How the three month period in between will be interpreted remains unclear. Members should probably plan for compliance with the earlier date to avoid possible problems. 

19 May 08 All ships must have obtained the IAPP (International Air Pollution Preventative) certificate. N.B.: This is the latest date. Many vessels will need to comply before then - see earlier article

01 Jan 10 Maximum sulphur content of bunker fuels for ships alongside berths in any EU port - 0.1%. Anchorages will probably also be included, subject to distance off shore. (EU directive).