For the 2020 deadline, there are basically four choices available:
- Switching from high-sulphur fuel oil (HSFO) to marine gas oil (MGO) or distillates: Switching to distillate fuels will mean a significant increase in fuel cost and may also require upgrading to a fuel treatment plant due to the significantly lower viscosity of the fuel. Fuel tanks previously used for HSFO must be carefully cleaned before bunkering MGO to avoid contamination and non-compliance problems.
- Using very-low-sulphur fuel oil or compliant fuel blends (0.50% sulphur): Low-sulphur-compliant fuel blends are expected to be available in the market through a variety of products. New fuel blends may experience compatibility problems, which will make fuel handling very important for safe operation. Quality control when bunkering to ensure that on-spec fuel is received will be important. The ISO Fuel Standards working group is planning to publish a Publicly Available Specification (PAS) in 2019, entitled “Considerations for fuel suppliers and users regarding marine fuel quality in view of the implementation of maximum 0.50% S in 2020”. The PAS is intended to provide guidance for both fuel suppliers and ship owners, and ensure a smoother transition towards 2020. IMO has also published a “Guidance on Best Practice for Fuel Oil Purchasers/Users for assuring the quality of fuel oil used on board ships”.
- Installing exhaust gas cleaning systems (scrubbers), which allows operation on regular HSFO: HSFO will still be an option after 2020. However, to be in compliance, it will require the installation of exhaust gas cleaning technology commonly known as SOX scrubbers. No changes will have to be made to the engines or fuel treatment plant, but the installation of a scrubber could be complex, especially for retrofits. There is a significant investment cost for the exhaust gas cleaning plant, and there will also be operational expenses related to increased power consumption and the possible need for chemical consumables and sludge handling for hybrid and closed-loop scrubbers.
- Using LNG or other sulphur-free fuels: LNG is expected to gain a more favourable position as an alternative for marine fuel for complying with the global sulphur cap. LNG as ship fuel is now a technically proven solution, and bunkering infrastructure is developing rapidly around the world. While conventional oil-based fuels will remain the main fuel option for most existing vessels, the commercial opportunities of LNG can be interesting for newbuildings. Taking the leap to LNG should only be made based on the best possible information and a thorough analysis.
There is a variety of emerging fuels that could also be considered as compliance options for the global sulphur cap. There are currently a few vessels operating with methanol as fuel, and several gas carriers have been ordered which use LPG as fuel. Switching to these types of fuel will need engines, fuel tanks and fuel management systems to be adapted.