Scrubber Technology Surpasses Low-Sulfur Fuels in Shipping
The International Maritime Organization’s 2020 cap on sulfur content in marine fuels has sparked a significant shift in the shipping industry. A recent study by researchers from MIT and Georgia Tech reveals that using exhaust gas cleaning systems, or scrubbers, with heavy fuel oil can be as environmentally friendly, if not more so, than burning low-sulfur fuels. This finding challenges previous assumptions about the environmental impact of scrubbers and highlights the need for comprehensive lifecycle assessments in fuel selection.
Understanding the Scrubber Advantage
Heavy fuel oil, commonly used by bulk carriers, has a sulfur content that exceeds the International Maritime Organization’s (IMO) cap of 0.5% in most ocean areas. This high sulfur content contributes to air pollution and health issues, prompting shipping companies to seek alternatives. The three main options available include burning low-sulfur fossil fuels, installing scrubbers to clean exhaust gases, or using biofuels. While the latter two options are viable, the installation of scrubbers has gained traction due to their cost-effectiveness and efficiency.
According to the study, which involved a detailed lifecycle assessment, burning heavy fuel oil with scrubbers can match or exceed the environmental performance of low-sulfur fuels when considering a wide range of factors. The researchers analyzed data from the production and operation of scrubbers and fuels, alongside emissions measurements from a cargo ship. Their findings indicate that, across nearly all ten environmental impact factors studied, including greenhouse gas emissions and ozone formation, the scrubber option is the least harmful.
Neil Gershenfeld, an MIT professor and senior author of the study, emphasized the importance of basing environmental claims on scientific data. Lead author Patricia Stathatou noted that the study fills a critical gap in understanding the holistic environmental impacts of scrubbers compared to low-sulfur fuels. The research, conducted in collaboration with maritime shipping firm Oldendorff Carriers, appears in the journal Environmental Science and Technology.
A Comprehensive Lifecycle Assessment
The researchers conducted a thorough lifecycle assessment, considering the entire supply chain of each fuel type. This approach is crucial, as producing low-sulfur fuels involves additional processing steps that contribute to greenhouse gas emissions. The study found that when accounting for these factors, heavy fuel oil emerges as a more environmentally friendly option than low-sulfur alternatives.
Inside the shipping team-up that helped manage the shift to very low sulphur fuel oil (VLSFO)
To gather accurate data, Stathatou spent a week aboard a bulk carrier in China, measuring emissions and collecting seawater and washwater samples. The results showed that scrubbers can reduce sulfur dioxide emissions by 97%, placing heavy fuel oil on par with low-sulfur fuels. Furthermore, the researchers tested washwater samples for over 60 chemical parameters, finding that most concentrations were significantly below regulatory limits set by the IMO and other environmental agencies.
These findings suggest that scrubbers, when used with heavy fuel oil, can be considered an environmentally sound choice. Scott Bergeron, managing director at Oldendorff Carriers, highlighted the study’s contribution to ongoing discussions at the IMO, advocating for regulatory decisions grounded in scientific evidence. The research underscores the necessity of incorporating lifecycle assessments into future environmental policies, ensuring that all fuel options are evaluated fairly.
