What fuel is used in ships today?
Ships are fuelled with heavy oil which is formed as a residue when the refining process turns crude oil into lighter fractions such as diesel, gasoline, etc. This oil, known as Bunker C or simply ‘fuel oil’, contains on average three percent sulphur and forms sulphur dioxide when it is burnt. This contributes to acidification. However, Wallenius sets a limit on the maximum allowable sulphur content of fuel oil purchased. The average for the whole fleet must not exceed 1.5 percent. Heavy oil, which is almost like tar, requires chemical additives and heating in order to become liquid so that it can be pumped. The oil also needs to be filtered and separated in a large onboard installation before it can be utilised in the engine.
Why can’t you just fill up ships with ordinary diesel, like a car?
In theory, you could do this, and we would certainly like to. In practice, however, it would be far too expensive, as the price difference between heavy oil and diesel is too great.
How can you reduce the dependence on fossil fuel?
There are various possibilities depending on how long into the future you look. In the short term, we’re thinking about reducing fuel consumption by streamlining energy use. This could be, for example, through recycling waste heat and the design of the vessels. In the longer term, we hope and believe that a combination of alternative energy where fuel cells running on hydrogen or methanol is the key, complemented by solar cells, wind power etc.
Recently, there’s been a lot of talk about the ballast water problem. What is it?
Ballast is seawater pumped into a vessel to increase its stability. If a ship has a small and light cargo, water is pumped into ballast tanks to weigh down the ship and increase its stability. When the cargo increases in weight, this ballast water has to be pumped out, otherwise the vessel would be too heavy. The problem is that this water contains a large number of undesirable organisms that can spread into a new environment. Since many of them are moved long distances, they sometimes have no natural enemies in their new homes and can propagate themselves and damage or destroy the local marine environment very quickly and easily.
How do you prevent organisms from moving between the different oceans?
Ballast water can be purified before it is pumped out. Our sister company Wallenius Water has developed a technology that purifies ballast water without leaving any damaging residues in the water. The technology is called Wallenius AOT™, and is the heart in the ballast water treatment system PureBallast, which has been developed by Wallenius Water and Alfa Laval. PureBallast is the first chemical free system in the world that has obtained IMO (International Maritime Organization) approval.
What do you use for painting ship bottoms?
As long ago as 1996, we stopped painting ships with tin-based bottom paints (TBT paints), which were subsequently banned by the IMO in 2003. That is why we continue to test non-toxic paints that use material such as silicon to create a very smooth surface to which living organisms cannot attach themselves.
The main reason for painting the bottom of a ship is to prevent the growth of organisms which attach themselves to the ship's bottom. These increase the resistance in the water which works to reduce speed and raise fuel consumption. This also increases the emissions that we do not want. Another issue is that bottom paints often contain toxic materials.
Why don’t you use wind power for electricity generation when the ship is on the open sea?
Today we are looking at the possibilities of applying wind power without loss of speed or reliability while at sea. We should be able to use sails of various types to tap the power of the wind to reduce fuel consumption. There are also tests being undertaken concerning the deployment of large ‘skysails’ to harness wind power to augment forward propulsion. Another possibility is to use wind turbines.
What do you do with the waste produced on board?
All our waste is sorted on board and deposited ashore at appropriate locations. Food residues are ground on board and dropped into the sea as fish food. Cardboard is burned on board in incinerators. Glass is sorted into dark or light and deposited ashore, as are plastics, metal, tins, batteries, fluorescent tubes, etc. The difficulty is that few ports around the world take our sorted waste and handle it properly. We are also trying out baling machines which compress cardboard etc into bales to be taken ashore.