Famous marine consultancy and classification firm Lloyd’s Register is old enough to have seen wind power come, go and come back again. The firm has just put its stamp of approval on a new type of sail that will help cargo ships meet the targets of EEDI, a key energy efficiency and carbon emissions index established by the International Maritime Organisation.
EEDI and wind energy for cargo ships
Wind power is free, but the shipping industry gave up on sails generations ago, after fossil energy entered the picture. Despite the recent move in a more sustainable direction, heavy “bunker” diesel is currently the fuel of choice.
“Many vessels still burn heavy bunker fuel, a viscous, carbon-intensive petroleum product left over from the crude oil refining process,” explain our friends at the technical engineering organization IEEE.
With thousands of cargo ships at sea, that’s a lot of bunker fuel. As the IEEE notes, cargo ships are a mainstay of the global economy (except for port communities, which have both land and sea pollution in their hotspots). The amount of cargo carried by water quadrupled to 10.3 billion metric tons from 1970 to 2016, and the number of ships operating today is approaching 100,000.
Decarbonizing the shipping industry will not be easy. Consumers might help by consuming fewer things, but consumers are only part of the complex web of interests that keep ships afloat.
The ultimate responsibility lies with industry, which has launched several industry-leading carbon reduction initiatives in recent years. Above those efforts is EEDI, the Energy Efficiency Design Index. Described as “the first legally binding agreement on climate change to be adopted since the Kyoto Protocol”, the EEDI was launched in 2011 under the United Nations International Maritime Organization.
“EEDI for new ships is the most important technical measure and aims to promote the use of more energy-efficient (less polluting) equipment and engines,” explains the IMO. “EEDI requires a minimum level of energy efficiency per mile of capacity (eg, ton mile) for different ship types and size segments.”
Here are Rotor Sails
EEDI is designed to gradually tighten energy efficiency targets. Progress has been slow, but electrification and alternative fuels are coming into play. Tweaks like route optimization can also reduce emissions, but the most exciting news from a cleantech perspective is the reintroduction of wind power, including retrofits for older ships as well as new builds (the retrofit comes under the IMO’s EEXI platform for energy efficiency).
Wind energy harvesting devices that vaguely resemble conventional sails are part of the mix. The shipping industry is also going further, into sails that don’t look like sails at all.
The Lloyd’s approved sail is a rotorsail. These are vertical cylinders that rotate and look like large chimneys. Although it is new on the boating scene today, the basic technology dates back to the 20th century. The initial concept is attributed to Finnish engineer Sigurd Savonius, and they were first tested on a trip across the Atlantic in 1926 by German inventor Anton Flettner, who gave the technology his name.
This brings us to the Lloyd’s Register and new principal approval for bulk carrier Newcastlemax, a new 210,000 DWT (deadweight tonnage) cargo ship designed by the Shanghai Institute of Merchant Ship Design and Research and fitted with rotor sails by Anemoi Marine.
“Newcastlemax AIP is part of a pioneering joint development project (JDP), signed in 2020, with Anemoi Marine Technologies, Lloyd’s Register and SDARI and brings together OEMs, classification societies, ship designers and ship owners to develop a range of energy efficient rotorcraft designs, ” explains Anomie, adding that Oldendorff Carriers is a partner of the shipowner.
“The installation of rotor sails on this bulk carrier, as part of our JDP with Anemoi, SDARI and Oldendorff Carriers, will significantly improve the efficiency of the vessel and is a clear example of how energy saving devices can support the maritime industry with the upcoming EEXI and CII regulations” , adds Lloyd’s.
Power of wind power
Digging into the weeds of EEDI is a whole ‘nother kettle of fish, so let’s just take Lloyd at his word for that double-digit improvement. As quoted by Anomie, Lloyd’s “confirmed that the newbuild Newcastlemax will have an EEDI score reduced from 1.92 to 1.37 (a 29% reduction) by fitting six 5x30m rail rotor sails and 1.47 (a 23% reduction) by fitting four old Rotor Sails 5x35m. ”
As for how it works, it’s easy. “The rotor sails are driven by the engine,” Anemoi explains. “When the wind flow meets the rotating rotor sails, a pressure difference is created. This causes a thrust force that provides auxiliary propulsion to the vessel and can be used to increase the speed of the vessel or reduce the consumption of the main propulsion unit.”
If you’re wondering how rotor sails handle bridges, that’s easy too. They can be designed to tilt to a horizontal position on the ship’s deck to accommodate a small clearance.
Anomie added an extra twist. To ensure that the sails do not interfere with cargo loading, their rotor sail system is both tiltable and movable.
“For vessels with complex cargo operations, such as Bulk Carriers, Anemoi has developed a patented rail deployment system. This allows our rotor sails to move along the ship’s deck so that the cranes can efficiently load and unload without obstacles,” the company explains. “Depending on the deck layout, the rotor sails can be moved from side to side (transverse) or along the length of the ship (longitudinal).”
Next steps for rotor sails
An EEDI improvement of 23-29% could be just the beginning. Last month, Dutch marine research organization MARIN launched a new EU-funded initiative called Optiwise, which aims to squeeze more action out of high-tech sails by optimizing ship systems around wind power, rather than treating wind power as an add-on.
“Our overall ambition is to develop and use holistic design and control methods for revolutionary new concepts of wind-powered ships, considering realistic operational scenarios. With these methods, we expect to achieve average energy savings of between 30% and 50% compared to equivalent conventional ships, while ensuring operational feasibility in a realistic wind climate,” explains MARIN.
The effort was put into full steam. Partners in Optiwise are Core IC, SSPA, AYRO, Chantiers de l’Atlantique, Flikkema Innovation Management & Consultancy, Wärtsilä Netherlands, Università degli Studi di Genova, Euronav and Anemoi Marine as a collaborator funded through the UK.
In addition, last month MARIN also partnered with the US Bureau of Shipping’s Service Classification Organization to launch the second phase of an initiative called WiSP, for wind-assisted ship propulsion.
“WiSP2 will focus on making evaluations within EEDI and EEXI, but also from real operational conditions. The aim is to prove the level of fuel savings that ship owners can expect, enabling them to make informed investment decisions while keeping in mind the upcoming CII requirements, they explain.
Like MARIN and Lloyd’s, ABS is another organization with roots in the sailing era. If America’s fossil energy interests encouraged the judicial death of the Clean Power Plan, they may want to put away those pom-poms and check out the ABS’s opinion on decarbonisation. Based in part on the rapid uptake of liquid natural gas as an alternative fuel, ABS is steering a course that has more to do with new clean technology and less with fossil energy business as usual.
Follow me on twitter @TinaMCasey.
Image: Rotor Sails courtesy of Anemoi Marina.
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