FuelEU Maritime is designed to reduce greenhouse gas emissions from shipping. But the same climate benefit can have very different consequences for air quality and the marine environment. A new report from the Swedish Environmental Research Institute (IVL) shows that fuel choices will determine whether the transition also cuts emissions of nitrogen oxides, particulate matter, and polluted scrubber water.

The debate on shipping's transition typically focuses on how greenhouse gas emissions can be phased out by 2050. To support this development, the EU has introduced regulations such as FuelEU Maritime, which will progressively reduce the greenhouse gas intensity of marine fuels. However, low climate emissions do not automatically mean low environmental impact. A new study by the Swedish Environmental Research Institute (IVL), funded by the Swedish Transport Administration, shows that ships meeting exactly the same climate requirements can produce very different levels of nitrogen oxides, sulphur oxides, particulate matter, and contaminated scrubber water.

“Climate targets can be achieved using several different fuels, but the consequences for air quality and the marine environment may vary considerably depending on the fuel chosen,” says Julia Hansson of IVL, who led the project Potential Environmental Effects of FuelEU Maritime Focusing on Swedish-Related Shipping.

FuelEU Maritime entered into force in 2025 and introduces increasingly stringent requirements for the greenhouse gas intensity of fuels used by larger vessels. The intensity must be reduced by 2 percent in 2025, 6 percent in 2030, and then gradually to 80 percent by 2050. How shipping companies meet these requirements is up to them. Options range from biofuels and biogas to methanol, ammonia, hydrogen, and electricity.

So, how will FuelEU Maritime affect the environmental footprint of Swedish-related shipping? Using a model based on more than 12,000 vessels, the researchers compared eleven future scenarios in which ships operate on fuels including biofuels, LNG, biogas, methanol, ammonia, hydrogen, and electricity.

“In our scenarios, emissions of sulphur oxides and particulate matter decreased more rapidly with gas-based fuels such as LNG and LBG. In that respect, they have an advantage over other biofuels and electrofuels. However, methane slip remains an important issue to address for gas-based fuels from a greenhouse gas perspective.”

FuelEU Maritime also enables so-called pooling. This allows a shipping company to group several vessels into a common pool and calculate compliance based on the performance of the fleet as a whole rather than on each individual ship. If a company exceeds the requirements by using more renewable fuel than necessary, it generates a surplus that can be sold to other operators that are struggling to meet the targets.

“The pooling mechanism has encouraged several actors to invest in renewable fuels on a larger scale than they otherwise would have. That effect came quickly. The market and industry stakeholders solved it faster than one might have expected, largely because some actors were early movers.”

However, there is a paradox. The pooling model is based on the fleet doing exactly enough to avoid penalties and no more. As a result, investments in alternative fuels tend to be concentrated in the vessels where they have the greatest impact, meaning that fewer ships are actually converted. Consequently, more conventional vessels can continue operating on fossil fuels, leading to higher emissions of sulphur oxides (SOₓ), particulate matter (PM), and continued use of scrubbers.

According to the report, signs of this development can already be seen in Sweden. Individual vessels with high fuel consumption are using LBG (liquefied biogas) to offset continued fossil fuel use in other parts of the fleet.

The report Potential Environmental Effects of FuelEU Maritime Focusing on Swedish-Related Shipping was authored by Nils Jutblad, Elin Malmgren, Julia Hansson, and Erik Fridell at the Swedish Environmental Research Institute (IVL).