In an advisory issued on October 28, CARB (the California Air Resources Board) said that ULSFO (ultra-low sulphur fuel oil) contains sulphur close to the 0.10% limit. This can be a high risk of non-compliance according to Californian low sulphur regulations. The shipboard in-use samples collected and tested by CARB staff have sometimes been found to exceed the regulatory limit. The California OGV Fuel Rule requires vessels to use only marine distillates within 24 nautical miles (nm) of its coastline except under a ‘research exemption’.
The (CARB) has warned ship operators that although the fuels were within the limit, “without taking precautions, there is a high likelihood of a violation”. The 0.10% sulphur limit applies to the North American emission control area (ECA), but also under the California Ocean-Going Vessel Fuel Regulation (OGV Fuel Rule).
Marine gas oil (MGO) sold in the US is very low in sulphur, averaging just 0.04%. Much of the MGO from other parts of the world is well below 0.10%. The alternative ECA fuels often referred to as ‘ULSFO’ are more likely to be blended products and based on heavy fuel oil (HFO).
CARB said the violations it had come across could be due to contamination of ULSFO at or near the 0.10% sulphur limit with higher sulphur fuels remaining in tanks, piping, and associated fuel handling equipment on board the vessel.
The possible steps to reduce the likelihood of noncompliance are as follows:
- Sourcing ULSFO with sulphur well below the 0.10% limit.
- Reduce the risk that residual high sulphur fuel oil (HSFO) in the vessels fuel system upsets the sulphur content in the product entering the engine.
- Avoid onboard contamination with even small amounts of HSFO in connection with fuel switching.
- Various onboard housekeeping that can reduce the risk of HSFO contamination in vessels’ fuel systems.
- Get the fuels tested by a reputable lab to verify product quality.
Source: Air Resources Board