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Tethered Sails Power Cargo Ships with Wind

Credits: ©2009 SkySails & KiteShip

It’s an idea that has been tested: a giant sail is attached to a heavy cargo ship, or smaller boat, to capture wind power, thereby reducing fossil fuel consumption, costs and pollution. One company, SkySails, reports that its kite sail will help reduce annual fuel costs by ten to 35 percent, with fewer harmful carbon emissions. The large towing kite resembles a paraglider and is shaped like an aircraft wing to enable it to take advantage of different wind directions. It operates at 100-300m above surface level - much higher than a normal sailing craft - where winds are stronger and more stable. The kite can be used in winds of 12-74km/h (7-40 knots) and not just when the wind is blowing directly from behind the ship. Here, we look at two different kite systems from two companies, SkySails and KiteShip.


Kiteship in Ocean

California-based company KiteShip makes “very large free-flying sails”— basically, giant traction kites that harness the wind to pull very large free-floating objects, such as cargo ships. ©2009 Kiteship


Maritime shipping is entirely dependent on oil. Over the past 20 years, crude oil prices have risen annually by 10 percent on average. This development places tremendous financial pressure on the shipping industry as fuel costs account for more than half of a ship's operating expenses already today.

Irrespective of the current economic crisis, there is no end in sight to this trend: The IEA (International Energy Agency) projects an average oil price level of US-$ 100 per barrel over the period 2009 to 2015 and expects prices to double to approx. US-$ 200 by the year 2030. According to the IEA the main reason for this price increase is the continuing decline in oil production rates (6.7% p.a.) facing a growing demand of 1percent per year. Without massive investments, this development will ultimately lead to a widening gap in supplies and further price increases.

According to SkySails, use of its technology can save large quantities of fuel. Consequently, ship operating costs drop significantly, and economical acquisition and operating costs for the SkySails-System lead to short amortization periods of between three and five years according to the company.

So far no sail system has been able to meet the requirements of today's maritime shipping industry. SkySails is offering a wind propulsion system which meets these requirements.

The technical possibilities resulting from the spatial separation of the ship and the “sail” or towing kite give SkySails an entirely new performance spectrum. The towing kite of the SkySails propulsion can be navigated “dynamically”. This means that the autopilot can perform flight maneuvers with the towing kite such as the figure of eight in front of the ship. SkySails easily generate five times more propulsion power per square meter sail area than conventional sail propulsions. Plus, the ship's regular crew is adequate for operating the system and no additional personnel costs will arise.

The textile towing kite is easy to stow when folded and requires very little space on board ship. A folded 160m² SkySails for example is only the size of a telephone booth. In contrast to conventional sail propulsions the SkySails-System has no superstructures which may obstruct loading and unloading at harbors or navigating under bridges, since the towing kite is recovered as soon as the 3-mile zone is reached. Unlike conventional forms of wind propulsion, the heeling caused by the SkySails-System is minimal and virtually negligible in terms of ship safety and operation. The SkySails-System is used parallel to and for relief of the main engine, if wind conditions allow. The main engine's propulsion power remains fully available if required.

Virtually all existing cargo vessels and new builds can be retro- or outfitted with the SkySails auxiliary wind propulsion system. Its universal design opens up an attractive market for the SkySails-System: Some 60,000 of the worldwide approximately 100,000 ships listed in Lloyd’s Register and about 1,100 of the 1,900 newly built vessels joining the world's merchant fleet each year are predestined to be outfitted with SkySails propulsion.

SkySails plans to equip 1,500 cargo ships and fish trawlers, as well as numerous super yachts, with SkySails propulsion by the year 2015. This represents a cumulative revenue potential that is far in excess of 1 billion euros. A total of about 10,000 SkySails-Systems are expected to be in operation by 2027.

Thanks to its broad applicability in the shipping sector, the SkySails-System can make a major contribution to curbing climate change. The systematic and worldwide use of SkySails technology would make it possible to save over 150 million tons of CO2 a year, an amount equivalent to about 15% of Germany's CO2 emissions.

For the first time in the history of commercial navigation, shipping companies are required to significantly reduce their ships' emissions for reasons of safeguarding the climate. Already today and in addition to the rising price of oil, operating costs are increasing considerably due to these legal regulations. In April 2008 the IMO approved a reduction in sulfur emissions for the shipping industry. From the year 2020 shipping companies either have to use distillate fuels with a limited sulfur content of 0.5 percent instead of heavy fuel oil or have to use scrubbing technology to clean their exhaust gases.

Already today the maximum sulfur content for ship fuels is limited to 1.5% in the so-called SECAs (Sulfur Emission Control Areas) on the North Sea and Baltic Sea. This threshold will drop to 1 percent starting in 2012. This is nothing more than a requirement to burn MDO/MGO, since it is not possible to reduce the sulfur content of heavy fuel oil to this level. For shipping companies using distillate fuels means a doubling of fuel costs in the future, since refined products such as MGO and MDO are considerably more expensive than highly sulfurous bunker oil.

In addition to that, the IMO is currently working on a regulation on the reduction of CO2 emissions from shipping in the form of a CO2 indexing scheme. Experts assume that corresponding regulations will be implemented in a timely manner. Thus, shipping companies will also be burdened with emissions-based levies in the future.

It is a simple issue: if no fuel is combusted, there are no emissions. SOx and NOx emissions can be reduced by retrofitting ships with exhaust-gas cleaning systems, however, technologies presently available to reduce emissions unfortunately and paradoxically increase fuel consumption and thus CO2 emissions. In addition to the high investment costs these technologies entail, operating costs increase by up to 5% as well. Obviously, it is smarter to reduce emissions by reducing fuel consumption, and this is exactly the solution the SkySails-System offers. Shipping companies thus benefit in two ways: they reduce emissions and their operating costs at the same time.

*The installation of emissions-reducing exhaust-gas cleaning systems entails tremendous costs for shipping companies. With such a system, fuel consumption rises by about 3 percent due to increased resistance in the exhaust line. Besides the expenses for maintenance and operation, the cost of procuring such catalytic converters runs about 40,000 euros per 1,000 kW of ship's power. Moreover, the highly toxic residues from the cleaning systems then have to be disposed of at great expense in port.

Within the framework of the pilot phase, the SkySails-System was being explored on board the MS “Michael A.” and the MS “Beluga SkySails” during regular shipping operations. Throughout these trials the system’s level of robustness and reliability is first of all being elevated to that demanded by our customers and its suitability for daily use established. Subsequently the system’s performance will be evaluated extensively and optimized.

On both ships – the “Michael A.” and the “Beluga SkySails” – the SkySails-System has been put into operation successfully. The customer vessels remain in regular commercial operation throughout the pilot phase. Initially, two to three SkySails engineers will be aboard of each ship. All components are being long-term tested during use of the SkySails-System on board. The results immediately flow into the process of improving and optimizing the product. Read full update…

On her maiden voyage, the Beluga SkySails set sail to Venezuela from Bremen on January 22, 2008 and reached the Norwegian port of Mo-I-Rana on March 13, 2008 after travelling a total of 11,952 nautical miles.

In January 2008, BBC News made the following report:
By Steve Rosenberg

BBC News, Bremerhaven, northern Germany
There is something rather magical about being up on deck of a giant cargo ship as it pushes its way out to sea.

Ten thousand tonnes of metal heaving through the water, the ship's giant masts glistening in the winter sun.

But there is something even more magical about being aboard MS Beluga SkySails.

On the face of it, this vessel - which is carrying parts of a timber production line to Venezuela - looks like any other cargo ship.

In recent months, commercial shipping has been criticised for not doing enough to tackle global warming.

Of all the CO2 being pumped into the atmosphere today, 4% comes from ships. That's more than the aviation industry, primarily because 90% of global trade is done by sea.

MS Beluga SkySails believes it has a solution. It has set sail on a mission to turn the oceans green.

Once the ship has reached the open sea, it reveals its brand new weapon in the fight against global warming: a kite.

Twisted spaghetti

The 160sq m (1,722sq ft) blue-and-white kite is winched up a mast, strings dangling like twisted spaghetti.

For half-an-hour or so, it sits there at the top of the mast, not doing a great deal. Wind power is a wonderful thing, but you do actually need some wind to make it all work - and there is not very much at this particular moment.

Half-an-hour later, though, the wind has picked up and the kite is flying hundreds of metres in the air - and helping to tug the ship along.

Kite power means the ship's engines down below can work on reduced power: and that means fewer carbon emissions.

It also means smaller fuel bills. With the price of shipping fuel having doubled in the past two years, kite power is promising big savings.

MS Beluga SkySails believes its fuel bill will be cut by £800 ($1,560) a day.

"We can demonstrate that you can combine economy and ecology," Verena Frank of Beluga Shipping explains.

"Economy, because you can reduce fuel consumption and fuel costs, and on the ecological side of things, we reduce emissions."

Magic wears off

The kite is controlled by computers. One computer helps it to fly in figures of eight in the sky - maximising the power it produces. Another computer adjusts the kite's direction.

If the project is successful, expect to see even bigger kites soon - some up to 5,000sq m (53,820sq ft) in size pulling ships across the seas and oceans.

After several hours on board the ship, the magic starts to wear off.

The sun has gone down, it is freezing cold. To warm myself up I start thinking of the ship's final destination - Venezuela.

But I will not be seeing the South American sun. By the evening, the ship has returned to chilly Bremerhaven to drop off the journalists, before setting sail - again - on its transatlantic journey.




New Wind Power Tech Could Change Cargo Shipping

KiteShip Making Breakthroughs
By: Terry McSweeney

SAN FRANCISCO, Sep. 21, 2007 (KGO) -

An East Bay company is hoping to harness wind power in a way that could change cargo shipping forever. It's a new twist on a very old technology.

The first sailing ship came into San Francisco Bay through the Golden Gate in 1775. There's nothing new about wind power. But there is something very new about the big plans to harness much more of that power.

A huge kite was on the Bay last weekend (Sept 2007) helping pull a 140 ton workboat from the Golden Gate Bridge to Alameda. KiteShip Corporation of Alameda put on the combination demonstration and experiment to promote this form of wind power. Company executives say it can reduce cargo ship fuel consumption by 10-25 percent -- which would be huge savings.

"Ships burn $1 million, $2 million, even $5 million dollars of fuel per year," said Dave Culp, KiteShip Corporation.

And it would clean up the air filling those kites.

"Every gallon of fuel not burned is three gallons of worth of CO2 that doesn't go into the atmosphere, its huge amounts of sulfur dioxide that doesn't go into the atmosphere, huge amounts of nitrous dioxide that doesn't go into the atmosphere," said Dave Culp.

KiteShip's Dean Jordan assessed the partially windpowered cruise -- not all went so smoothly.

"We didn't get a practice and we had to fabricate all the equipment we used on the vessel to steer the kite," said Dean Jordan, KiteShip Corporation.

There was trouble with one of the three wenches.

"The line would come on the wench and then lock up," said Dean Jordan.

Still the experiment was educational. Jordan and Culp worked together in the 90's on a kite for the Oracle/BMW team in the America's Cup Yacht Race. He says had those on board the yacht deployed their kite, which was an approved spinnaker replacement sail -- the USA would have defeated New Zealand and this type of wind power would be famous by now.

"Can you imagine Oracle wins America's Cup by flying a kite - It would have made headlines around the world!" said Dean Jordan.

KiteShip hopes its next video will allow it to make headlines by engineering a 13,000 square foot kite to co-power vessels up to 600 feet in length saving $300,000 dollars in fuel per year, per vessel.

It seems it's not a matter of if but when for this technology -- companies in Europe and Asia are all working on this technology. The folks at KiteShip say the future is near. That those huge kites will be helping to haul huge cargo ships in three to five years.

Copyright 2007, ABC7/KGO-TV/DT

Original article


  Mortality from Shipping Emissions Article 2007 (1,058 kb)

  Mortality from Shipping Emissions Supporting Material 2007 (1,162 kb)