The International Maritime Organization (IMO) has set a 4.5 percent cap on sulphur content in marine fuels with the MARPOL 73/78 Annex VI Regulations. The regulations aim to prevent air pollution from ships, and entered into force on 19 May 2005.

Following a study by Dag Olav Halle of DNV Petroleum Services (DNVPS), it was found that the sulphur levels in marine fuels had actually gone up.

"DNVPS statistics indicate that bunker deliveries with sulphur content above 4.0 percent have risen over the last two years, even though just 0.2 percent of global marine fuel deliveries contained more than 4.5 percent sulphur. This implies that the actual number of deliveries exceeding 4.5 percent sulphur is relatively insignificant, which in turn could mean that a worldwide 4.5 percent sulphur cap alone may not do much to reduce overall sulphur emissions," says Dag Olav Halle.

Emissions could rise
Following the trend documented by the study, it was reported in a recent DNVPS bunker bulletin that several deliveries in Singapore last month marginally exceeded the MARPOL Annex VI 4.5 percent sulphur limit. Deliveries containing up to 4.8 percent sulphur were also detected in a few Italian ports.

"So there's a chance that total sulphur emissions are actually rising, despite the 4.5 percent cap imposed by the new Marpol regulations," says Dag Olav Halle.