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Set sail for a greener world

5 propulsion methods to reduce emissions

The maritime industry is changing, with official regulations, new technology, and, not least, the environmental zeitgeist playing an important role. Shipping is becoming greener. The basic approaches to environmentally friendly freighters and other vessels are diverse—some are already on the horizon, while others currently only exist on paper. Here is an overview five propulsion methods that can reduce CO2 emissions.


Liquefied natural gas (LNG) is a fuel that is beginning to take off. From cruise ships to oil tankers, around 200 ships will soon be using natural gas for powering their combustion engines. And this trend will continue to rise, thanks to environmental regulations such as the global sulfur cap set by the IMO. In comparison to diesel or fuel oil, LNG reduces CO2 emissions by approximately 25–30 percent.

Flettner rotors

In 1924, the Magnus effect was first used by a ship. This technique, which for a long time was disregarded, is now gaining popularity again. Rotor ships feature large rotating cylinders, known as Flettner rotors, which are mounted on the deck and use the Magnus effect to increase propulsion. Two examples of this concept are the E-Ship 1 freighter—a diesel-wind power hybrid completed in 2010—and a tanker experiment currently being conducted by Maersk. Even in the 21st century, Flettner rotors could still have a significant role to play.

Kite shipping

Kites generate immense traction in strong winds. And ships equipped with kite sails can use this phenomenon to their advantage. A large kite pulls these giants of the ocean at a force of up to 6,800hp, reducing fuel consumption by as much as 20 percent. As an upgrade for today’s ships, the technology is comparatively quick to implement and use. However, in practice the system is currently not particularly widespread. At present, there are only a handful of commercially operated ships equipped with kite sails.

Wind solar panels

At sea, there are three elements: water, wind, and sun. By using EnergySail, technology company Eco Marine Power is interested in just the latter two in order to get through the first. Panels installed on the ship convert wind and sunlight into power. One advantage of this is that a vessel can recharge for free when in the docks. The engine is effectively an add-on for existing ships and is combined with a LNG-powered combustion engine. The panels are currently being tested in active operation, with a view to starting production next year. It will be interesting to see how the technology progresses.

Windship concept

If the Norwegian, Terje Lade, has his way, giant windships will be sailing the seas in the future. His ultimate vision is that freighters will emit 60 percent less fuel and 80 percent less exhaust fumes. The basis for this is a combination of LNG and wind power. Therefore, his Vindskip (Norwegian for windship) has no sails—it is its own sail. The shape of the almost 50-meter tall vessel somewhat resembles an iron—its large surface area is designed to catch the wind and convert it into powerful force that propels the ship forward. But can this ship design really be put it into practice on the world’s oceans?


While cleaner shipping concepts are diverse, many of them leverage the wind. The advantage of this resource is clear: it doesn’t cost anything, it is emission free, and there is an unlimited supply of it. However, as today’s alternative propulsion methods do not provide the same amount of force as fossil fuels, hybrid solutions are inevitable. Ultimately, they do show that the industry is realigning and has already set sail for a greener world.