By Dag Olav Halle, DNV Petroleum Services.

Two months into the implementation of MARPOL Annex VI, ships plying international routes are steadily incorporating regulations 14 and 18 on fuel sulphur limits, sampling procedures and bunkering documentation into shipboard practice.

These vessels invariably have to overcome teething problems expected with the introduction of any new requirements. On the other hand, there are a number of major issues which can threaten the success of MARPOL Annex VI if they remain unresolved.

At the time of writing, several countries with substantial bunker supply volumes have not yet ratified MARPOL Annex VI. These include the Netherlands, Belgium, France, Italy, Australia, Brazil, Venezuela, Canada, USA, Egypt, Iran, Iraq, South Africa, the Philippines, South Korea, the United Arab Emirates and China. Among them are some of the world’s top crude and fuel exporters.

Since MARPOL Annex VI became effective on May 19, vessels have been confronted with complications resulting from taking bunkers in non-signatory countries before sailing to a destination where the regulations are in force. Particularly, if the ship is entering or flying the flag of a signatory state, she must show evidence of using bunkers not exceeding 4.5% (m/m) in sulphur content. The attendant sampling and documentary requirements are not always met with ready cooperation from the supplying party.

To pre-empt possible difficulties, ship operators should order fuels against ISO 8217 and also specify in the bunker purchase contract that the supplied fuel must comply with regulations 14 and 18 of MARPOL Annex VI.

While the supplier is responsible for providing the MARPOL sample for each grade of fuel delivered, the ship crew should ensure the right procedures are followed, regardless of whether MARPOL Annex VI is applicable in the bunkering port concerned.

If the supplier fails to meet any of the requirements, for instance the bunker delivery note (BDN) is missing or a representative MARPOL sample is not passed to the vessel for retention, the ship crew should send a note of protest (NoP) to the flag administration and take their own MARPOL sample according to the specified procedures.

For authentication purposes, the bottle label for the MARPOL sample prepared by the ship crew must be counter-signed by the supplier’s representative. And if the vessel is subsequently subjected to port state inspections after leaving the bunkering port, the ship crew should present both the issued NoP and their own MARPOL sample to the officials.

Regulatory considerations aside, a study of worldwide fuel sulphur levels by DNV Petroleum Services has yielded some interesting findings.

Firstly, the study reveals that over the past two years, approximately 0.2% of global marine fuel deliveries contained more than 4.5% sulphur. This figure implies that the actual number of high sulphur deliveries on a global scale is relatively insignificant and as such a worldwide 4.5% sulphur cap alone would not do much to reduce overall sulphur emissions.

On the other hand, DNVPS statistics however do suggest that bunker deliveries with sulphur content above 4.0% have risen over the same period (see table below).

Worldwide sulphur levels in marine fuels

During the six weeks after MARPOL Annex VI came into force, some suppliers appeared not to have managed to remove their >4.5% sulphur fuel cargoes from the market yet.

As reported in a recent DNVPS bunker bulletin, several deliveries in Singapore last month marginally exceeded the MARPOL Annex VI 4.5% sulphur limit. Deliveries containing up to 4.8% sulphur were also detected in a few Italian ports.

Not surprisingly, the suppliers involved disputed these findings.

In analysing fuel sulphur content, DNVPS applies the ISO 8754 test method specified in Appendix VI of MARPOL Annex VI. Before reporting any results found to have exceeded ISO 8217 (maximum 5% m/m) or MARPOL Annex VI limits, the fuel samples are re-tested and the published data derived by averaging two or more readings obtained on the same sample.

The high sulphur fuels from Singapore last month were in fact retested at two DNVPS labs, both ISO 17025 accredited, and the separate results matched one another.

As part of their quality assurance efforts, DNVPS laboratories participate in two round robin programmes, namely, the Shell Main Products Correlation Scheme and the American Society for Testing and Materials (ASTM) Inter-Laboratory Cross-Check Programme on Fuel Oil. Their consistently good showing in these programmes lends support to the reliability and accuracy of DNVPS’ test results.

Accurate reporting of fuel quality is clearly important as it can influence operational decisions. In this regard, high sulphur fuels are known to contribute to low temperature corrosion of engine parts and this in turn affects crew and cargo safety.

Ship operators should also note that fuels from some areas may generally contain higher levels of sulphur, and that this element has a negative impact on fuel energy content.

Fuel sulphur comes from the crude slate used in the refinery. During the different stages of crude and fuel refining, sulphur accumulates in the bottom residue, from which nearly all marine fuels are produced.

Hence, if the original crude oil contains high sulphur content and severe refining techniques are also in use at the refinery, bunker buyers can expect more sulphur in the manufactured marine fuels.

The apparently increasing fuel sulphur levels observed in certain regions could be due to a more extensive use of high sulphur crudes combined with heavier and more viscous fuels delivered to the ships. Compared to a fuel oil with, say, 2.5% sulphur, bunkers with 4.5% sulphur would contain 1.5% to 2% less energy per kilogram of fuel. This translates into a relative loss of about US$4/t at today’s heavy fuel oil prices.

Whether the 4.5% global sulphur cap and the 1.5% limit in the forthcoming Sulphur Oxide Emission Control Areas (Secas) can effectively lower SOx emissions remains to be seen.

For now, DNVPS fuel quality statistics suggest that even as most deliveries are within the 4.5% sulphur limit, fuel sulphur content in certain areas and involving specific suppliers are apparently on the rise.

It would be interesting to observe if the supply of high sulphur fuels in some areas will be balanced by lower sulphur levels in other regions, or whether the introduction of the Secas will lead to the trading of higher sulphur fuels in other parts of the world.

We can however predict with much greater confidence that if worldwide sulphur levels in marine fuels do go up, the International Maritime Organisation and the European Union will press for a further reduction to the sulphur cap.

Rather than taking a protectionist approach towards their respective bunker industries, ports states can play an important part in lowering SOx emissions by ensuring that the requirements spelled out in MARPOL Annex VI are adhered to and that fuels from their suppliers stay well within the stipulated sulphur limits.

Bunker buyers and suppliers who need further clarification on MARPOL Annex VI issues can consult the flag state, the port state, classification societies, fuel testing companies and maritime bodies such as Intertanko, Intercargo, IBIA and Bimco.

Dag Olav Halle is Technical Task Force Manager at DNV Petroleum Services. He is based in Singapore. For enquiries on marine fuel management or MARPOL Annex VI issues, please email singapore@dnvps.com.