Using Liquefied Natural Gas (LNG) as a Fuel for Ferries in Stockholm, Sweden

Context of Transport Climate Action

Fuel used for shipping is often highly polluting (both in terms of Greenhouse Gas GHG and local emissions) and the use of LNG can reduce the amount of these pollutants and GHG emissions by 15 %[1]

Using LNG reduces NOx levels by around 92%and SOx emissions are almost entirely eliminated. It is therefore considered as an interesting alternative fuel for heavy road transport, inland, short sea and maritime shipping.

The Port of Stockholm now allows vessels to bunker (store) this fuel on board.

The construction of LNG storage infrastructure is also in line with the European Union’s Alternative Fuels Infrastructure Directive.

One of its goals is to create a network of LNG fueling points in Europe’s main ports to allow the industry to shift to using more LNG and away from traditional marine fuels.

Also, the storage facilities enable more LNG powered vessels to be used and meet the stringent rules of the ECA (Emission Control Area) in the Baltic Sea and North Sea.


The Viking Grace was the first large passenger ferry in the world to operate on LNG.She works out of the Port of Stockholm, where 6 times a week she is refueled by a special purpose vessel. The bunkering vessel lies alongside the Viking Grace to transfer LNG. The creation of the LNG storage and refueling facilities were crucial for the Viking Grace to operate on LNG. The ferry is now fully operational now and the benefit include GHG emission reductions and other local air pollutants.

It’s success required the cooperation of the ship owner, the port, and the gas company. Numerous actors had to work together to this project work:  Kari Granberg from Viking Lines stresses the importance of the partners: the  Swedish Transport Agency (KlasJungmark), the Finnish Trafi (Sten Sundberg), the gas supplier AGA (Jonas Åkermark), Meyer Turku ( VesaAiraksinen), Wärtsilä (Ingvar Öst), Lloyd’s Register (Jan von Bergmann) and many more.


Bunkering a full-size ferry had never been done before, so the ship owner Viking Lines collaborated closely with the port authorities and AGA, the gas supplier to find the best way to do this.The main partners were Viking Line, actively delivering passenger transport services in the Baltic, the Port of Stockholm, owned by the Swedish state and the municipality of Stockholm, and AGA, a leading gas company in Northern Europe. The project was co-financed by the European Union within the TEN-T  program. This collaboration developed  the first LNG ferry to operate in Stockholm and built a special purpose bunkering vessel to optimize the bunkering procedure.

Apart from the technical challenges in the development of the bunkering facilities, safety, operational and legal aspects are very important when using LNG as marine fuel. Some of the operational challenges were ensuring the security area of 25 m around the bunker vessel and complying with the visual safety requirements from both vessels’ bridges.In addition, special training was needed for the crew members. Emergency exercises for the crew, theoretical courses for the engineers and simulation based training for engineers were also set up.

Due to the complex nature of this project and its high potential for CO2 emission reductions,  the project received a grant of € 28 million.


Using LNG as a fuel for shipping can reduce the CO2 emissions by up to about 25 %[1]Using LNG however leads to unburnt fuel emissions,so called “methane slip”, which has a slightly negative effect on the overall emission gains. Therefore, the total Green House Gas reduction may only be 15%.

The emission of local air pollutants is lowered significantly (NOx by about 92%, SOx and soot almost entirely). In addition, the vibrations and noise on board are reduced, improving the passengers’ experience on board.

The port of Stockholm can now also facilitate other LNG powered vessels.

Potential for scaling up

The port of Stockholm now has the facilities to bunker LNG vessels. The concept can be further optimized, more special purpose fueling vessels can be ordered to allow more ship-to-ship bunkering, and other ports can learn from the experience, which is gained in Stockholm.

In Europe there are about 950 car ferries from with about 90 in the high capacity category (including the Viking Grace). It is hoped that this Viking ferry can serve as an example for other ferries..Ports can also develop bunkering facilities which target other market segments as well, the  inland shipping industry for example is also starting to adopt LNG.

[1]In direct CO2 emissions.

Selected references



Europe, Sweden






Europe, Sweden, mitigation, Technology, Freight, Passenger, Partnerships,


Viking Lines, Ports of Stockholm, AGA


Kari Granberg

“There was a great teamwork from all stakeholders. We all had the same goal: that Viking Line's new cruise ferry would have LNG as fuel. We managed to do what no-one had done before:to bunkerLNG simultaneously with the boarding of passengers and loading and unloading of cargo was a real challenge”
-Kari Granberg, Project manager NB, Viking Line.