The maritime industry is turning toward wind power. The International Maritime Organisation has strict rules about cutting the emissions. Three years ago, it prohibited the use of sulfur rich fuels by vessels. A decision that was controversial, some scientists believe that sulfur emissions actually were helping the atmosphere to create more clouds and clouds were reflecting the sunlight, countering the effects of climate change and global warming.
Anyway, the International Maritime Organisation has also set a zero emission target for navies and vessels by 2050. And many giant cargo firms are starting to search for other sources of energy. Battery technology cannot at present power ratings work much beyond small craft operating on short routes. But wind power is becoming more alluring. On the other hand, little infrastructure exists to make and distribute green fuels like biofuels, hydrogen and ammonia, and these fuels are still quite expensive. Hence, even for ships that use alternative fuels, harnessing the wind will help reduce costs and emissions further.
The concept of vessels using wind power through some other instrument than sails, has been around for more than 100 years. An odd vessel made its way across the Atlantic and arrived in New York in 1926. This sailing vessel was renamed Baden-Baden after being transformed. Its two masts were demolished, and in their place were two 15-meter-tall rotating cylinders fixed to the deck. Before cheap oil caused interest to diminish, the rotors were regarded as a significant achievement at the time (praised by Albert Einstein, among others). It was called Flettner cylinders. Flettner rotors are still a desirable option. The rotation of the revolving cylinders causes an area of high air pressure on one side and reduced air pressure on the other as the wind blows around them. The Magnus effect, which also aids in the curvature of spinning balls, produces a force at an angle to the direction of the wind as a result of this pressure differential. It produces lift on a horizontal airplane wing. On a vertical rotor, it facilitates forward ship propulsion. The rotors may be “trimmed” to the dominant wind conditions by turning them in different directions and at varied speeds. As everything is done automatically, no extra workers are required.
One of the firms that supplies Flettner rotors nowadays is Norsepower, a Finnish company. It claimed to have struck the largest wind-propulsion agreement ever earlier this year when it was ordered to equip each of the three newly constructed cargo ships for French shipping magnate Louis Dreyfus Armateurs with six 35-meter rotors. The European aerospace company Airbus will be the charterer of the vessels. Each will transport enough half built aircraft—wings, tails, and fuselages—for six A320 airliners to be put together in Airbus’s American plants.
Source: Economist
