Investing in technologies that prevent emissions affecting the marine environment or causing air pollution is relatively inexpensive compared to the societal costs caused by these emissions. This is shown by new findings from the research project EXIT, funded by the Swedish Transport Administration.

Since 2020, under the EU’s so-called Sulphur Directive, the sulphur content in marine fuels must not exceed 0.5 percent. Even stricter regulations apply to the Baltic Sea, the North Sea, and the English Channel, where only fuels with a sulphur content of no more than 0.1 percent are permitted.

"The Sulphur Directive has been very effective in reducing actual sulphur emissions and thereby the socioeconomic costs. In the Mediterranean, for example, the cost of emissions has decreased from almost four billion euros per year to around half a billion euros per year since 2020," says Rasmus Parsmo from IVL, one of the researchers in the EXIT project – External Costs, Policy Instruments and Cost-Effective Measures for Sustainable Shipping.

The installation of scrubbers – purification systems that wash ship exhaust gases of sulphur pollutants – has been a relatively inexpensive solution from a business or shipowner perspective compared to using low-sulphur fuels. However, scrubbers have also caused significant socioeconomic damage, as the polluted wash water, which contains heavy metals and other harmful substances, is often discharged directly into the sea.

"Reducing this type of discharge – so-called marine ecotox emissions – could potentially be even more cost-effective than reducing air pollution. Preliminary estimates indicate that the cost of these emissions in the Baltic Sea amounts to around 16 billion euros per year. For example, there are non-toxic alternatives to traditional antifouling paints that could save society large sums. For shipping companies, it may even be cheaper to use biocide-free, silicone-based paints than traditional copper-based variants," says Parsmo.

In this three-year research project, the researchers have mapped the societal impact of shipping through a framework for calculating the external costs of various emissions and their effects on human health, climate, and the marine environment. They have also analyzed policy instruments for more sustainable shipping, focusing on what is cost-effective from the perspective of shipping companies. Additionally, they have examined how policy analysis and external costs can be combined in scenarios that assess the future impact of shipping on the environment, health, and climate.

When it comes to nitrogen oxide (NOx) emissions, which affect human health and contribute to eutrophication and forest acidification, better policy instruments are needed. Although the societal costs of these emissions have decreased somewhat in recent years, shipping still accounts for a large share of the transport sector’s NOx emissions.

"If the shipping sector is to meet established climate targets, better policy instruments are also needed to reduce greenhouse gas emissions. The current price of emission allowances in the EU ETS is far too low to drive reductions. It is therefore cheaper to continue using traditional fuels and buy allowances than to switch to fossil-free fuels. FuelEU Maritime, which came into effect this year, is more effective as it imposes direct requirements on the shipping sector. All vessels over 5,000 gross tons calling at European ports must gradually reduce the greenhouse gas intensity of the energy used onboard," says Rasmus Parsmo.

The report EXIT – External Costs, Policy Instruments and Cost-Effective Measures for Sustainable Shipping was authored by Rasmus Parsmo (IVL), Erik Ytreberg (Chalmers), Selma Brynolf (Chalmers), and Erik Fridell (IVL).