International shipping is a major source of sulfur, nitrogen oxide and carbon dioxide emissions. Replacing conventional shipping fuel with liquefied natural gas, LNG, makes it possible to greatly reduce the environmental impact of shipping.

The international shipping industry now accounts for about 4 percent of annual global emissions of sulfur, 7 percent of emissions of nitrogen oxide and less than 3 percent of carbon emissions. Environmental innovation in the maritime sector plays an important role in the efforts to tackle global climate change. In addition, the shipping industry emits other particles that have been proven to be harmful to humans.

There are also tougher regulations on sulfur content in crude oil-based marine fuels on the horizon. The International Maritime Organization, IMO, has set upper limits for sulfur content. The Swedish shipping industry will impose even stricter requirements than many of its European counterparts. It is becoming a commercial necessity to find alternative solutions to ensure a competitive and environmentally friendly shipping industry.

Liquefied natural gas

LNG is a potential solution to the shipping challenges, and there is already a commercially viable option for smaller vessels. In Norway, some ferries run on LNG with more to come. LNG offers the ability to reduce sulfur oxide and nitrogen oxide emissions significantly. Potentially, carbon emissions could be cut by 20 percent.

Today, the sulfur content in marine fuel must be at most one percent. By 2015, marine fuels should contain at most 0.1 percent sulfur. Perhaps using LNG can help attain this goal.


In May 2011, AGA opened the Baltic Sea’s first LNG terminal where the gas is transported in liquid form. During transport, the fuel is cooled to minus 162 degrees, shrinking the volume by a factor of 600. This makes transport more efficient as more fuel can be transported at a lower cost and with less emissions. Other Baltic terminals are planned.

Good but not perfect

The benefits of LNG are fairly obvious. It offers significantly lower emissions of sulfur, nitrogen oxide and particulate matter compared to conventional shipping fuels. Carbon dioxide emissions are also lower.

The infrastructure for processing LNG, however, is still inadequate. It will take time and require significant investments to increase the percentage of ports that can provide vessels with LNG.

It is therefore likely that boats (passenger ships, ferries) that traffic the same harbors will be the first to use LNG.

Construction lead times in the shipping industry are also long. This means that it will take time for a significant portion of the world’s fleet to change its fuel.

In addition, it costs a lot of money to convert motor systems to use LNG. At the same time, outfitting a ship to run on LNG means that it no longer needs cleaning equipment that is required for other fuel. The working environment on board is also improved.


The proportion of vessels using LNG as a fuel is low, but increasing. It is by no means a perfect fuel from an environmental perspective. Some emissions still occur. But compared to conventional shipping fuels there are many advantages. LNG is a fuel that can be used in an economically sustainable way with existing technology.

It is therefore likely that LNG will in future play an increasingly important role in the shipping industry’s efforts to reduce their environmental impact.

The article was published in November 2011