More shipping companies are turning to sail power in the pursuit of fuel savings and ecological integrity
Two of the most recent groups to embrace what is technically known as wind-assisted propulsion are France’s Louis Dreyfus Armateurs (LDA) – which in July announced it would install an Airseas kite system on the roro Ville de Bordeaux which delivers Airbus parts around Europe – and another French group Neoline, which has ordered the first of two, 136-m long roro cargo vessels featuring four soft, fold-away sails. The group says these will complement a 4,000-kw diesel-electric propulsion system and cites a delivery date for the first of the vessels as the end of 2021.
The main attraction with this technology is clearly fuel costs. Neoline expects to slash fuel consumption by an astonishing 80-90% from no less than 4,200 m2 of sail area. Neoline’s roro, which will be built by a Pays de la Loire-based collective called Neopolia Marine, will connect western France with North America. It seems that the two roro vessels will be the first sail-assisted ships to be built by Neopolia Marine. According to its website, its most recent delivery was a river cruiser.
LDA president, Edouard Louis-Dreyfus, is optimistic about the future of the technology for his group, which boasts a fleet of more than 100 owned and chartered vessels. “We are very excited by the development of wind solutions as a key answer to the decarbonisation challenges we are facing today,” he said in a statement. As a sign of his enthusiasm, in July Louis Dreyfus became the latest member of the not-for-profit International Windship Association (IWSA). The group declined to answer more detailed questions about its plans for sail-assisted power, but it is known that the shipping company is involved in further tests and, a source suggested it has signed non-disclosure deals with several wind-specialist companies.
These latest commissions conclude a bumper couple of months for wind-assisted technologies. In June, Japan’s K Line committed to installing up to 50 Airseas kite systems, subject to test results. Dipping its toe in the water, K Line will mount a kite, known as a Seawing, on the bow of one of its bulkers. The crew will not however be expected to battle with billowing sails – the kite is controlled from the bridge by a simple switch that automatically unfolds or refolds it. If the K Line deal goes ahead as expected, it would mark the biggest-ever individual investment in wind-assisted power in merchant shipping.
On top of K Line’s announcement, two important yards, Samsung Heavy and Hyundai Heavy, have unveiled their own rotor sail technologies for very large crude carriers.
Just a start
According to IWSA secretary-general Gavin Allwright, the latest announcements are just the start of something big in the 21st century commercial fleet. “Wind-assisted and primary-wind propulsion is increasingly being viewed as a credible and economic option,” he said. “All of the technologies have great potential of 5-20% and up to 30% as retro-fits, and significantly more as optimised new builds.” With more than 100 members, IWSA is in the middle of launching regional hubs around the world, starting with Nantes, France, dedicated to Europe and the Atlantic. In July, a red-letter month for IWSA, classification society Bureau Veritas jumped aboard the organisation. “A key focus area for Bureau Veritas is supporting safety and new technology to reduce emissions,” says the society’s global technology leader for sustainable ships, Panos Koutsourakis. “The time is right to further develop the wind propulsion sector.”
A growing number of shipping groups seem to agree. Also in July, American Bureau of Shipping and consultancy Marin joined up with several other parties to assemble hard data. They include Finland’s Norsepower, China’s Ship Scientific Research Centre, Dykstra naval architects in the Netherlands, Germany’s Eco Flettner, Anemoi, a Flettner rotor specialist, and FinOcean. “A major barrier to the use of wind energy on board is the shortage of transparent and independently verified methods to predict the performance of wind propulsors,” argues Marin’s senior project manager for ships, Patrick Hooijmans.
Yet there are reasonably robust numbers out there, although estimates by shipping companies and consultants tend to vary, in part because the potential savings depend on the route, prevailing winds, target speeds and other factors. Louis Dreyfus expects savings of about 20% on its European run while the Netherlands’ wind-propulsion specialist eConoWind reports that one of its units installed on the cargo ship Lady Christina posted savings of 800 litres a day during a good stretch on its 25-day maiden voyage between Emden to Plymouth, then Plymouth to Rami and Pietersari. The minimum claimed savings for the vessel are 10%. Meantime studies posted by IWSA cite savings of 10-30% for motor vessels retrofitted with wind-assisted technologies, up to 60-70% in favourable winds, and average annual savings of over 50% for pre-designed hybrid wind and motor vessels. Pure wind-driven vessels, albeit fitted with auxiliary engines, can deliver up to 100% per cent savings.
The attractions are more than mere fuel savings though, explains IWSA’s Mr Allwright, citing a number of downstream benefits. “An increasingly important factor is that wind propulsion technology can be linked with other changes such as vessel and voyage optimisation,” he explained. “This reduces the amount of alternative low carbon fuel required, potentially less storage capacity and total power requirement. Thus [the technology] also facilitates the uptake of those systems in the market.”
On the water
Elsewhere, and among other developments Maersk is testing a Flettner rotor on the tanker MV Pelican and Viking Lines is following suit. Dalian Shipbuilding and China Merchants Energy are testing wing sails on a VLCC; and Blue Planet Shipping already has four Flettner rotor bulkers in operation.
To date, Flettner rotors, a century-old concept that ‘spins’ the wind, seem to be dominating. There are already rotor-assisted tankers, bulkers, roro ships, ferries and general cargo vessels on the water. A drawback of rotors, according to some studies, is that they require clear deck space and are unsuitable for certain types of vessels, such as roro and container ships. But other technologies are attracting interest, notably kites, which have been under development for a decade, and many versions of hardsails: “There will be a number of announcements in this sector in the next couple of months,” predicts Mr Allwright. Other alternatives include yacht-like soft sails, as on the Neoline roros, and even aircraft-like wings, also known as Ventifoils, that maximise thrust. “The first commercial installation [of wings] will be made quite soon,” says Mr Allwright.
Brussels, an advocate of wind-harnessed commercial shipping, estimates there will be some 10,000 installations worldwide by 2030. But if the current round of tests and installations delivers the promised gains, that prediction may prove to be conservative in the post-2020 world of greener seas.