It was a milestone for shipping and the environment: Since January 2020, the maximum sulphur content of marine fuels worldwide has been 0.5 percent rather than the previous 3.5 percent. The new sulphur oxide (SOX) cap is part of the MARPOL convention adopted by the IMO, which obliges the maritime industry to reduce its sulphur emissions as part of the organization’s resolute efforts to make shipping greener.
The IMO 2020 regulation applies to all large vessel types, including cargo ships, tankers, cruise ships, ferries and offshore supply vessels. The classification society DNV estimates that the regulation impacts up to 70,000 vessels worldwide.
Low-sulphur fuel oil (LSFO)
Shipowners have various options to meet the requirements. The simplest one is to switch to using low-sulphur fuel (LSFO) or high-quality marine gasoil (MGO) – meaning fuels with a very low sulphur content. This had been a common practice already before 2020: When entering an emission control area (ECA), such as the North Sea or Baltic Sea, where the sulphur cap for fuel has been just 0.1 percent since 2015, ships already had to switch to these types of fuels in the years before 2020.
Since 2020, high-sulphur fuel oil (HSFO), the former standard, may only be used in combination with an exhaust gas cleaning system (EGCS), commonly known as a “scrubber”. These kinds of filtering systems can reduce sulphur emissions by up to 99 percent. The process involves spraying the exhaust gases with seawater, which reacts with the sulphur oxide to form sulphuric acid. In addition to sulphur, the scrubbers also filter particulate matter from the system.
As the third alternative for compliance, there is the “big solution” – namely, switching to a low-emission fuel, such as liquefied natural gas (LNG). The combustion of this gas eliminates virtually all sulphur oxides and soot particles. Emissions of nitrogen oxides (NOX) are reduced by up to 80 percent and CO2 by almost 30 percent. In order to be able to bunker the natural gas, which has been cooled down to minus 163 degrees Celsius, the ships must be equipped with a special liquid gas tank and a dual-fuel generator.
By now, LNG propulsion has proven its viability as an alternative and eco-friendly technology – and not only for ferries or cruise ships. In fact, LNG is also becoming a more popular alternative in the container shipping segment.A spectacular showcase project among ultra large container vessels is the retrofitting of the “Sajir”, now known as the “Brussels Express”. Hapag-Lloyd’s 15,000 TEU container ship was outfitted with a dual-fuel engine at a Shanghai shipyard that can burn both LNG and low-sulphur fuel oil as a backup solution. What’s more, Hapag-Lloyd recently commissioned the construction of in total 18 ultra-large container vessels with dual-fuel engines.
Owing to the high costs associated with retrofitting vessels to be able to use LNG, smaller ship segments are more likely to prefer ordering new LNG-capable ships instead of retrofitting. One source of uncertainty continues to be bunker costs, as no one can predict how the price of LNG will develop compared to that of marine diesel. Numerous market factors – such as the importation of liquefied gas from the United States – play a role in this. While the competition for a national LNG site is still ongoing in Germany, other EU countries have had such terminals for some time now. In any case, Germany does have a mobile solution. As part of a joint venture, the Schulte Group recently deployed the world’s largest LNG bunker supply vessel ship, the “Kairos”.