Debunking bunkers

If shipowners want the cheapest fuel possible they have to accept that it may be of variable quality.

Residual fuels are not going to get any better. The oil majors point out that residual fuel is a product blended to meet ISO standards — but the reality is that the blending consists of adding just enough distillate to the leftovers from the refining process to meet those standards. This at least means that residual fuel should not get any worse. That said, a glance at the ABS bunker quality report (see Markets) will show that not all deliveries meet these standards.

Shipowners can take one of two courses of action: extra clauses or extra vigilance. Some owners keep adding additional clauses to the fuel purchase agreement to outlaw the latest undesirable elements, others prefer to look at what has been delivered and see if it can be used.

There are attractions to adding additional clauses to the fuel purchase contract. If the fuel does not meet an owner’s full specification he can demand that the supplier pay the cost of debunkering – but the supplier is unlikely to pay if the ship’s equipment can make the fuel useable. However, these additional demands effectively increase the cost of producing residual fuel, and the oil companies have other alternatives such as coking — indeed some refineries in the US have already decided to coke all residue. So it is a fine line between ensuring premium quality residual fuel and an owner pricing himself out of the market.

The other approach is to have the fuel analysed and see if the treatment system can make it useable without causing excessive work for the crew. But this can only be done if it is know exactly what is in the bunkers — and that means fuel analysis. Analysis of fuel samples usually include a measurement of its density and viscosity along with the percentage of water, ash and sulphur. Also measured is micro carbon, aluminium and silicon, sediment and vanadium. Most lab results also include the CCAI.