Green Shipping | Part 3: Spotlight: Sulfur emissions

Green Shipping | Part 3: Spotlight: Sulfur emissions

October 2020 | The “green” in Vogemann Green Ship Token is no coincidence: the digital security invests in sustainable ships. In our series “Environmental protection in shipping” we explain which pollutants are actually produced and what Vogemann is doing to contribute to greener shipping. Our topic today: sulfur oxide emissions. 

The majority of ships on the world’s oceans are powered by heavy fuel oil. This is a waste product left over from the processing of crude oil in refineries. It is comparatively cheap – but also quite toxic. It contains heavy metals, nitrogen oxides and sulfur, among other things. 

In the North Sea region alone, 20 to 30 percent of the sulfur and nitrogen oxides come from shipping. Shipping accounts for 8 percent of global sulfur oxide emissions.


Share of shipping in global sulfur oxide emissions

Exactly these are the ones who are in for it now:

Since January 1, 2020, the sulfur content of marine fuels worldwide has been limited to 0.5 % instead of 3.5 % – in the interest of clean air and better environmental and health protection. This is because sulfur oxide (SOx) emissions from ships’ combustion engines cause acid rain and particulate matter, which can promote respiratory and cardiovascular diseases and reduce life expectancy.

In addition, there are regions with even stricter sulfur limits. Such “Emission Control Areas” (ECA) or “SOx Emission Control Areas” (SECA) exist, for example, in China, the USA and the North and Baltic Seas, where the limit was already reduced to 0.1% in 2015.

What technical solutions are available for implementation?

Shipping companies basically have two options for ensuring compliance with the sulfur limits:

  1. operating the ships with marine fuels that have a correspondingly low sulfur content

And those do exist – Low Sulfur Fuel Oil (LSFO) are heavy oils that have been desulfurized and have a sulfur content of less than 1%. Ultra Low Sulfur Fuel Oil (ULSFO) even has a sulfur content of less than 0.1%. These can be heavily desulfurized heavy oils, but for cost reasons they are usually the already low-sulfur marine gas oil, which consists exclusively of distillates. 

  1. installing a desulfurization system (so-called “exhaust gas scrubbers” or “scrubbers”) on board the ship.

Ships with an installed exhaust gas scrubber may continue to burn fuel with a high sulfur content of 3.5%. The installation of such a scrubber is associated with considerable costs in the millions. The amortization of the installation costs should be achieved by lower fuel prices for bunkers with a high sulfur content.

Two different installations are distinguished here: 

In “open loop” plants the sulphur waste water accumulated during the cleaning process is disposed of into the sea. With “Closed Loop” systems, the sulphur wastewater is then disposed of on land. “Hybrid” plants can represent both systems.

“Open Loop” systems are much cheaper than “Closed Loop” systems, where the sulfuric wastewater is disposed of on land, and therefore most of the scrubbers installed worldwide are also of this model. However, in many “ECA” or “SECA” areas their operation is not (no longer) permitted for environmental reasons.


How does Vogemann deal with the requirements?

Vogemann has decided against the installation of “scrubbers” for several reasons and operates its own fleet with low-sulfur fuels instead.

This again shows the ecological approach of the shipping company. After all, there are doubts about environmental friendliness, especially with “open loop” systems. In addition, the operation of “open loop” scrubbers is no longer permitted in many ports and regions. The special feature of Vogemann’s Handysize bulkers, however, is that their size and equipment make them particularly flexible in use and allow them to call at various ports that larger ships cannot call at due to restrictions.

These are further reasons why Vogemann relies on low-sulfur marine fuels:



Exhaust gas purification systems installed on ships are technically complex and require a lot of maintenance. In addition, there are risks of failure: 

Sulfuric acid is produced during the exhaust gas cleaning process. The use of exhaust gas cleaning systems can cause corrosion damage, which in extreme cases can lead to water ingress with flooding of the engine room. Various classification societies have issued corresponding warning messages, as can be read here.



The profitability of scrubbers depends mainly on the fact that marine fuels with a high sulfur content are permanently available and much cheaper than fuels with low sulfur content within the limits.

In this sense, a scrubber installation is a bet on low(er) prices of high sulphur fuel. In the course of 2020, however, this bet has not yet paid off: 

After “High Sulfur Fuel Oil” (HSFO) was still around 400 $/tonne cheaper than “Low Sulfur Fuel Oil” at the end of 2019, the price advantage has currently (as of 19 May 2020) fallen to below 50 $/tonne in Rotterdam, for example. With this price difference, a “closed loop” exhaust gas purification system for a handysize bulker only pays for itself after more than 20 years.


Operational use:

Vogemann operates a fleet of handysize bulk carriers that regularly call at remote ports with only rudimentary infrastructure. In these ports, the fuel availability of “High Sulfur Fuel Oil” (HSFO) is often not guaranteed, which is why even ships with an installed scrubber must bunkers “Low Sulfur Fuel Oil” in these ports.


Would you like to find out more about environmental protection measures in shipping and how the Vogemann shipping company is further expanding its pioneering position in Green Shipping? Here you can find the introduction to our series. You can read the first parts about CO2 and greenhouse gases here.