How “green” is very low sulphur fuel oil (VLSFO)?

In recent years, international shipping has increasingly been subjected to criticism for its environmental record. It was in this context that the regulation issued by the International Maritime Organisation (IMO) prohibiting vessels from burning fuel with more than 0.5% sulphur content from 1 January 2020 onwards met with a generally favourable reception. As most ocean-going vessels had previously been burning fuel oil with a sulphur content of 3.5%, it was generally assumed that the very low sulphur fuel oil (VLSFO) would have a positive environmental impact, especially when ships are in port. So how about an initial fact check?

Supply shortages

Although it is still too early to identify longer-term trends, one or two key consequences of the IMO ruling have already become clear. The first, and most obvious, question is whether there is enough VLSFO for the world’s commercial shipping fleet of some 50,000 vessels. Initially, the answer was clearly no. For a variety of reasons, the bunker supply side was not ready for January 1. As early as mid-January, for example, Indian ports were running low on VLSFO, as refiners had not expected such high demand. Producing VLSFO is a challenge, especially if the crude oil a refinery receives is of high sulphur content, which is not unusual. However, refineries responded to the increased demand by tinkering with the technology. The number of fuel oil non-availability reports (FONARs) filed to the IMO fell sharply from 41 in January to just six in February. This was not only due to supply-side adaptation. The COVID-19 outbreak in Asia caused bunker demand to fall in February and the global spread of the coronavirus since then has dampened demand even further worldwide. In the meantime, it is not VLSFO unavailability that is the problem but a shortage of the more sulphurous variety (HFSO). To meet the growing demand for VLSFO, refiners have switched production away from HFSO and outside the main ports, HFSO has often been in short supply.

Dubious environmental credentials

A second question is just how environmentally friendly VLSFO actually is. A submission to the IMO funded by the German Environment Agency and assisted by the class society DNV GL and engine maker MAN ES shows that VLSFO causes higher black carbon emissions than high sulphur fuel oil. The higher emissions – between 10% and 85% – are most evident when engines are running at less than full capacity. As a result, various NGOs have already called for the use of VLSFO to be banned in ships sailing through Arctic waters. Black carbon is a potent climate-warming component of particulate matter. In the atmosphere it absorbs sunlight and re-emits the energy as heat; on ice or snow, it also causes the surface to absorb more sunlight, causing ice or snow to melt. This is particularly significant as the Arctic ice mass has been declining dramatically in recent summers.

Exceptional circumstances

Vessels are still allowed to burn heavy fuel oil if scrubbers are fitted. Although many ocean-going vessels do not have such scrubbers, they need not worry if they are passing through the Suez Canal. In January, the Suez Canal Authority (SCA) kindly announced that it would allow ships to burn conventional heavy fuel oil and not require them to use open-loop scrubbers when transitioning the waterway. The reasoning was interesting: the Arab Republic of Egypt has yet to ratify MARPOL Annex VI, IMO’s VLSFO regulation. Besides, the SCA pointed out, the wash water from exhaust gas cleaning systems was apparently polluting Egyptian waters. As a result, ships are now required to turn off their open-look scrubbers when navigating the Suez Canal so pollutants are released into the air rather than the water. Early days yet, but VLSFO does not appear to the entirely environment-friendly solution it was heralded to be. Stay tuned for more revelations as the year develops.

Meanwhile, you may have a look at the Vessel Emission Log feature of FleetMon. Receive estimated CO₂ emission calculations for any vessel within a selected time frame or for recent voyages. Visit the detail page of any vessel and select the Emission Log tab. The Emission Log records CO₂ emission for arbitrary date ranges of the vessel. FleetMon uses the vessel’s historical track from AIS signals as well as vessel particulars to estimate the amount of CO₂ emissions. For example, have a look at MARIBO MAERSK’s emission reports of recent voyages.