The discharge from ships with scrubbers is causing significant harm to the Baltic Sea. According to a recent study from Chalmers University of Technology, Sweden, these emissions have resulted in pollution that has led to socio-economic costs of over EUR 680 million between 2014 and 2022.
The study reveals that the shipping companies’ adoption of this technology, which involves “washing” exhaust gases and discharging them into the sea, has resulted in substantial cost recouping for most ships. This has allowed the industry to generate billions of euros by running its ships on cheap heavy fuel oil instead of cleaner fuel.
“We see a clear conflict of interest, where private economic interests come at the expense of the marine environment in one of the world’s most sensitive seas,” says Chalmers doctoral student Anna Lunde Hermansson, who is one of the authors of the new study, published in Nature Sustainability.
The urgent need to address the potential ban of scrubber water discharge from ships’ exhaust gas cleaning systems has prompted extensive discussions at various levels, including the International Maritime Organization (IMO) and the EU. This issue is also under consideration at the Swedish Parliament, although a decision on a ban is pending.
Anna Lunde Hermansson, along with Chalmers colleagues Erik Ytreberg and Ida-Maja Hassellöv, have conducted extensive research on the environmental impact of shipping. In a previous study, they revealed that over 200 million cubic meters of environmentally hazardous scrubber water are discharged into the Baltic Sea each year.
Furthermore, their research has starkly demonstrated that scrubber discharge water significantly contributes to up to 9% of the total emissions of certain carcinogenic polycyclic aromatic hydrocarbons (PAHs) into the Baltic Sea, posing a grave threat to marine ecosystems.
Recent research conducted by Chalmers researchers has meticulously assessed the external costs of scrubber water discharge and the financial performance of over 3,800 vessels that implemented scrubber technology. Regarding the detrimental impact on marine ecosystems, the study reveals that between 2014 and 2022, scrubber water discharges caused pollution at a staggering cost of over EUR 680 million in the Baltic Sea area.
These calculations are conservative estimates, as they do not encompass direct costs linked to heavy fuel oil spills from ships employing scrubbers. Additionally, they do not include the substantial expenses associated with cleaning up oil after ships have leaked, as exemplified by the Marco Polo incident on the Swedish coast of Blekinge last autumn.
“If the scrubbers had not existed, no ships today would have been allowed to run on this dirty residual fuel. That is why the scrubber issue is highly relevant to push the shipping industry towards less negative environmental impact,” says Lunde Hermansson.
From the shipowner’s perspective, the costs of installing and maintaining scrubber systems were carefully considered, along with the monetary benefits of using heavy fuel oil instead of more expensive low-sulfur alternatives. Based on calculations, most shipping companies that invested in scrubbers have already broken even, with a total surplus of EUR 4.7 billion expected for all 3,800 vessels by the end of 2022. The research also indicates that over 95% of common scrubber systems recoup their costs within five years.
“From the industry’s point of view, it is often stressed that shipping companies have acted in good faith by investing in technology that would solve the problem of sulfur content in air emissions and that they should not be penalized. Our calculations show that most investments have already been recouped and that this is no longer a valid argument,” says Lunde Hermansson.
Denmark recently announced a ban on scrubber water discharge within 12 nautical miles of the coast. Similarly, several other countries, including Germany, France, Portugal, Turkey, and China, have implemented national bans or restrictions.
Although there is no general ban in Sweden, certain ports like the Port of Gothenburg have prohibited scrubber water discharge in their area.
“We now hope that the issue will also be given priority in the Swedish Parliament. This is a low-hanging fruit where we can reduce our negative impact on the vital marine environment,” says Lunde Hermansson.
Journal reference:
- Anna Lunde Hermansson, Ida-Maja Hassellöv, Tiia Grönholm, Jukka-Pekka Jalkanen, Erik Fridell, Rasmus Parsmo, Jesper Hassellöv & Erik Ytreberg. Nature Sustainability, 2024; DOI: 10.1038/s41893-024-01347-1