As the shipping industry moves to decarbonize, huge sails could be making a comeback. The China Merchant Energy Shipping company (CMES) has taken delivery of a new supertanker, whose four large sails will cut down average fuel consumption by nearly 10%.
Sails, of course, were the primary source of power for large ships for thousands of years. Then German inventor Rudolf Diesel got his first engine up and running in 1897, and the first diesel-powered ships took to the water in 1903. Safer and more efficient than steam engines, they slowly took over the shipping world and have been a pillar of international commerce ever since. They're filthy, though, with some 50,000-odd merchant ships in service contributing around 1.7% of global greenhouse emissions, and while methanol and ammonia are viewed as promising cleaner energy alternatives, the technology is far from settled at this point.
Sails, however, are very well understood, and for at least 10 years we've been seeing concepts and plans to bring large airfoils back to the cargo and passenger shipping industries. Ireland's B9 Shipping put forth the idea of a 100% sail-powered cargo ship back in 2012, although it doesn't seem much has come of it. Wallenius offshoot Oceanbird has now bumped back the launch date for its first retractable rigid sail-powered ship from 2024 to 2026.
But China's Dalian Shipbuilding Industry Co (DSIC) has now delivered. The M/V "New Aden" is a 333-meter (1,093-ft) supertanker in the "very large crude carrier" class. Launched on September 24, this colossus runs a relatively modest, but groundbreaking wind power system. Four retractable sails, each rising 40 m (130 ft) from the deck and presenting a 1,200-sq-m (~13,000-sq-ft) surface, are mounted near the middle of the long deck.
These lightweight, corrosion-resistant carbon fiber composite blades can be raised or lowered at the touch of a button. An "Aerofoil Sails Intelligent Control" system is designed to constantly monitor the prevailing conditions, as well as navigation data, and continually adjust the angle of the sails to make maximal use of available wind.
As a relatively small implementation of the auto-sailing concept, this system isn't designed to be the primary driver. The ship will still burn lots of diesel. But on an example shipping route between the Middle East and Far East, it's expected to reduce average fuel consumption by more than 9.8%, saving an estimated 2,900 tons of carbon dioxide emissions each trip.
The New Aden is a crude oil supertanker, so for all its promise as a testbed for green technology, its primary purpose is still to ferry somewhere around two million barrels of heavily polluting fossil fuel around the world. But whether or not you'd view it as a greenwashing exercise, it'll clearly prove – or disprove – the economics involved with adding these huge sail systems to large, modern ships, and is thus an impressive achievement and a significant piece of technology.
Source: China Classification Society
