POSTED 25 DECEMBER 2007 - 11:00am HST

Rethinking the sail

image above: Commercial Ship deploys SkySail computer coordinated towing technology

Covered in the December 2007 Utne Reader &

Hamburg based SkySails uses a combination of conventional engines and giant, computer-maneuvered kites to power ships. With kites ranging in size from 160 to 5,000 square meters, the systems can cost a few million dollars to install.

By the use of a SkySails-System fuel costs can be lowered between 10-35% on annual average depending on actual wind conditions and achievable operational period. Under optimal wind conditions, fuel consumptions can temporarily be reduced up to 50%. Thus large amounts of expensive oil can be saved and the burden on declining oil reserves is reduced (see development of the oil price).

According to an up-to-date study from the University of Delaware (USA), the world trade fleet consumes approx. 280 million tons of oil or 2 times more than Germany (approx. 125 million tons) (see resources).

Since cargo ships run on extremely sulphurous fuel oil, their emissions damage our environment considerably (see toxicity).

Experts from Lloyd’s Register Quality Assurance (London) estimate that shipping traffic generates 7% of the total worldwide output of sulphur dioxide (SOx), and is thus one of the main causes of climate-damaging gases (see climatic impact). Through the consistent global use of the SkySails technology worldwide, it would be possible to cut over 146 million tons of CO2, which equals approx. 15% of the CO2 emissions of Germany.

In accordance with new regulations from the “International Maritime Organization” (IMO) ship owners will, in future, have to significantly reduce the toxic emissions of their ships. (see statutory provisions).

Development of the oil price
Since the fossil energy resources on our planet are limited, the prices of these resources are rising continuously. During 2005, numerous resource prices reached an all-time peak due to high demand (report "World Commodity Prices 2005 to mid-2007" of the resource working party of the AIECE (“Association d’Instituts Européens de Con-joncture Économique“ or “Association of European Conjuncture Institutes“). At the beginning of September 2005 the oil price reached an all-time high of 67 US dollars per barrel for Brent oil and over 70 US dollars for the WTI price (West Texas Intermediate = crude oil quality for pricing).

Current prognoses are for a continuing significant increase in oil prices: The high growth of demand can not be covered even by increasing output or opening up new oil resources. This is the conclusion of the study “strategy 2030 - energy resources” carried out jointly by the Hamburg-based Berenberg Bank and the Hamburg-based Welt-Wirtschafts-Institut (HWWI) (world economic institute). With regard to the development of energy resources markets, director Prof. Dr. Thomas Straubhaar from HWWI notes: “With a predicted annual average growth of the world economy of 2.8% for the period, the oil price, starting at just under 40 US-Dollars per barrel in 2004, could rise to 120 US Dollars by 2030.”

High oil prices considerably increase a ship's operating costs. Fuel costs already amount to more than half of the operating costs of a ship. Ship owners often deploy special “Fuel-Saving-Groups” to reduce fuel consumption in ship new builds.

Increasing efficiency using ship diesel has almost reached its maximum potential and is also extremely expensive. According to the calculation of an expert on ship propulsions, shipping companies would have to invest up to 500,000 Euros in order to reduce a ship’s fuel consumption by 1%. Fuel savings of 5% would be a fantastic performance for ship owners, according to Niels Stolberg, managing partner of Bremen-based shipping company Beluga Shipping GmbH.


Increasing economic globalisation and the concomitantly increased exchange of goods, has brought high growth rates in shipping, which have continuously outstripped the growth rates of the world economy. Thus, the capacity of the world trade fleet rose by 5.7% in 2005, while the global economy grew by just 3.1%. In 2002 experts of the WGBU (Wissenschaftlicher Beirat der Bundesregierung Globale Umweltveränderungen) (scientific advisory board of the German federal government on global environmental changes) predicted average growth rates of 1-4% for the coming years. According to the WGBU's data, the entire world trade fleet in 2001 consisted of approx. 41,000 cargo and passenger vessels (over 300 RT), within which were 10,000 tankers, 6,000 ships for dry bulk articles, 2,600 container ships, 18,000 general cargo and roll-on-roll-off-freighters, 2,500 combined cargo-passenger ships and ferries, as well as 1,500 passenger ships.

According to “Lloyd’s Register” a total of approx. 90,000 civil ships with over 100 gross register tons cross the oceans.

According to an up-to-date study from the University of Delaware (USA), the world trade fleet consumes approx. 280 million tons of oil or 2 times more than Germany (approx. 125 million tons) (see resources).

The biggest environmental problem is that 90% of ship diesels (the standard propulsion for medium to large tankers, bulk barrier and container ships are slowly-operating two-stroke diesel engines) run on a comparatively cheap, but highly contaminated fuel oil. The low-grade fuel oil is a viscous substance, which is a by-product residual at the end of crude oil production. It consists of all the components of crude oil unusable for the production of petrol or diesel fuel.

Fuel oil with low sulphur levels (MDO/MGO quality) costs almost twice as much as the IFO 180 and IFO 380 qualities predominantly in use.

During the combustion of fuel oil large quantities of toxic substances pass into the air. In comparison to other substances fuel oil has characteristics causing considerable environmental pollution. Fuel oil contains up to 5% sulphur depending on its origin. Low sulphur levels have to be calculated at a cost of a minimum of 20 (currently approx. 50) Euros per ton and percent (according to the ISL (Institute for maritime traffic economy and logistics) 2001; from: special survey 2002 WGBU (Scientific advisory board of the federal government global environmental changes)).

The combustion of fuel oil mainly produces nitric oxides (NOx). A 90-95% reduction of NOx emissions through, for example, the installation of ship catalysts, requires the investment of approx. 40,000 Euros per Megawatt (MW) installed propulsion power. Additionally, costs for operating supplies and increased fuel consumption have to be covered.

Nitric oxides (NOx) react with hydrocarbons (HC) under the influence of sunlight, generating ozone and leading to smog. Sulphur oxides can aggravate respiratory illnesses and are a cause of “acid rain”. Ozone leads to breathing difficulties in humans and damages flora.

image above: ship under way with towing assist from SkySail

Climatic Impact

Cargo shipping is one of the main causes of climate-damaging emissions and thus contributes substantially to environmental pollution. According to a study from the University of Delaware (11/2003), cargo shipping emits the same amount of nitric oxides as the entire USA. Additionally, according to investigations by the German journal “Bild der Wissenschaft 1/2006”, commercial shipping is the 3rd largest source of climate-effecting toxic substances after industry and road traffic.

Experts from Lloyd’s Register Quality Assurance (London) estimate that, with an annual output of 10 million tons, shipping traffic generates 7% of the total global output of sulphur dioxide (SOx).

A special survey of the WGBU (2002) reaches a similar conclusion: global shipping traffic is responsible for approx. 7% of the CO2 emissions of the traffic sector, or for approx. 2% of global CO2 emissions. Furthermore shipping accounts for approx. 7% of all SO2 and 11-12% of all NOx emissions.

According to current calculations by scientists from the Hamburg-based Max-Planck-Institute for Meteorology (Prof. Hartmut Graßl, 11/2005) climate will change more quickly than ever before in the coming century. This is the conclusion of the latest climate model calculations of various scenarios up to 2100. Global warming, resulting from climate change, is already noticeable worldwide in the form of extreme weather, such as Hurricane Katrina in the USA. Expert opinion predicts that such extreme weather occurrences, including those involving heat aridity and precipitation, will become more frequent and more extreme in the future.

Greenhouse gas concentrations are presently higher than they have been at any point in the last 650,000 years. This is the opinion of a European research team in collaboration with scientists from the Alfred-Wegner-Institute of Polar and Maritime research. Prof. Dr. Thomas Stocker from the Physical Institute of the University of Bern substantiates this fact: “Analysis shows that, at 0.38 parts per thousand by volume, today's level of atmospheric hydrocarbon is 27% percent higher than the highest level measured during the last 650.000 years.”

Dr. Veronica Eyring from the Institute of Physics of the Atmosphere (Deutsches Zentrum für Luft- und Raumfahrt e.V.) (German Centre for Aerospace) notes the following global toxic emissions of the shipping industry in 2002:

CO2: 813 million tons per year (in 2001)

NOx: 21.4 million tons per year (in 2001)

SO2: 12.0 million tons per year (in 2000)

Statutory provisions

Substantial cost pressure will arise for ship owners in future due to the introduction of emission-dependent charges in cargo shipping.

The ‘International Maritime Organisation’ (IMO), a sub-organisation of the UN, is responsible for ship safety and the prevention of pollution caused by ships at an international level. In order to reduce air pollution caused by ships the IMO enacted laws on 19th May 2005 (MARPOL 73/78, Annex VI) regulating threshold values for the emission of SOx and NOx and controlling the emission of ozone-reducing substances by ships. These laws include the stipulation of a maximum sulphur level of 4.5% in heavy oil internationally, and a maximum sulphur level of 1.5% in ‘SOx Emission Control Areas’. The English Channel is a SOx Emission Control Area, as the Baltic Sea will be from the beginning of 2006, and the North Sea from the beginning of 2007. The regulation stipulates that ships can either be fitted with a flue able to clean waste gases or with an arbitrary technology which reduces SOx emissions.

Additionally, the IMO is preparing for the implementation of a CO2-indexing-scheme in order to reduce the CO2-emissions of ships. Ships with low CO2-emissions will be in a favourable position with regards to emission-dependent charges.

Reducing greenhouse gases through the installation of a flue able to clean waste gases comes with high costs for shipping owners. According to Stephan Brabeck, development manager at SkySails in Hamburg, fuel consumption rises by up to 3% due to increased drag in the exhaust pipeline. Along with servicing and lubricant costs, investing in a catalyst costs approx. 40,000 Euros per 1,000 kW propulsion power of a ship. The highly toxic residues of purification plants have to be disposed at harbours at considerable expense.

Somebody remembered how to do it
by Juan Wilson on 25 December 2007

image above: The Royal Clipper, the largest sailing vessel afloat

The Royal Clipper, built in 2000, is the first fully-rigged square-rigger with five masts since her inspiration, The Preussen, in l902. Preussen was the largest sailing vessel ever built to that time. Fully rigged means squaresails on each of the masts. Royal Clipper approximates Preussen in all major measurements. She is by far the largest true sail vessel afloat anywhere today.

Classification and registration: Royal Clipper as flagship of Star Clippers joins Star Flyer and Star Clipper in being built to high safety, construction and rigging standards, confirmed by Lloyd's Register of Shipping. .The steel-hulled vessel carries the highest rating possible: (Sailing Passenger Vessel) " spv +100 A1" and is designed to pass all safety and equipment ratings of the United Nations, and of U.S. Coast Guard.

She is registered out of Luxembourg and will operate under the respected high standards of the Belgian Maritime Authority. Royal Clipper has been built at Merwede Shipyard, near Rotterdam, The Netherlands. Dimensions: Length is 439 feet. Beam is 54 feet Draft is 18.5 feet Gross Tons: 5,000 (compares with 2,298 gross tons for sister ships, Star Flyer and Star Clipper). Size of crew: 105, of whom only 20 are needed to handle all sails.