Ferries in European ports emit more pollution than millions of cars

Road traffic is not the only enemy of clean air. The latest study shows that ferries are another one. In Europe, they emit more carbon dioxide than 6.6 million cars. Their exhaust fumes are also a source of huge amounts of sulfur oxides. Which ports are the most polluted?

Life by the sea is overrated

The analysis prepared by Transport & Environment (T&E), a group working for clean transport, examines emissions from ferries moored in European port cities and compares them with the harmfulness of car exhaust fumes. The results are very alarming.

Passenger and car ferries are an important part of the transport system in port cities, enabling access to nearby islands and relieving congested highways. Most of them operate regularly, day after day, with each voyage emitting huge amounts of carbon dioxide and sulfur compounds. In the EU, there are 904 ro-pax vessels and 1,012 passenger ferries in operation, accounting for 26 percent and 22 percent of the global fleet respectively. They spend more than 60 percent of their time within five nautical miles of densely populated areas, significantly contributing to coastal air pollution.

Currently, the highest ferry emissions are recorded in Dublin, the Canary Islands port of Las Palmas, and the Welsh port of Holyhead. The dirty ranking of ports compiled by T&E also includes Santa Cruz de Tenerife, Belfast, the Greek port of Piraeus, and the French port of Calais. The most polluting ferry route was identified as the connection between Helsinki in Finland and Travemünde in Germany, followed by the surprisingly short routes Calais–Dover and Helsinki–Tallinn.

More harmful emissions than cars

T&E experts calculated that in 2023, 1,043 ferries moored in European ports emitted a total of 13.4 million tonnes of CO2, equivalent to the annual emissions of 6.6 million cars. Even more worrying are the figures for sulfur oxides from fuel burned on ferries. In Barcelona, they are 1.8 times higher than those generated by car exhaust fumes. Ferries in Dublin and Naples also release more sulfur into the air than cars.

According to the T&E analysis, the average age of ferries in European fleets is 26 years. Outdated technology contributes to greater environmental pollution, but it also provides a reason for change.

Ferries should connect communities, not pollute them. Too many of them burn polluting fossil fuels, pumping toxins into the air of Europe’s port cities, said Felix Klann, shipping policy officer at T&E, summarizing the current reality.

Electric ferries as an opportunity for cleaner cities

The transition towards cleaner maritime transport was initiated by Annex VI of the International Convention for the Prevention of Pollution from Ships (MARPOL). It introduces so-called Emission Control Areas (ECA), specially designated sea areas where stricter emission standards apply. In 2026, these include the Baltic Sea, the North Sea and the Mediterranean Sea.

According to T&E analysts, the new regulations will support the electrification of European ferries, which by 2035 could cover up to 60 percent of the fleet. The expected benefits include a 42 percent reduction in CO2 emissions, improved air quality in port cities and, importantly for investors, a significant reduction in connection costs.

Currently, the biggest barrier to electrification is inadequate port infrastructure. T&E calculations show that around 57 percent of ports would require only smaller chargers with a capacity below 5 MW, but this still excludes a significant number of ferries. A further challenge is charging speed, which is a serious limitation for vessels operating without longer breaks.