A secret to improving cargo ship efficiency: Go fly a kite
Designers look to giant kites, bubbles, and new propellers to save on fuel costs and reduce pollution.
from the April 3, 2008 edition
Page 3 of 4
When the cargo ship Beluga SkySails left the port of Bremen, Germany, in January, it carried with it a high-tech version of an ancient means of propulsion.
During its 11,952-nautical-mile voyage to Venezuela and back, the ship launched a giant kite from its bow, sending it hundreds of feet into the air to capture the stronger and more consistent winds found above. The 1,720-square-foot kite, controlled by onboard electronics, exerted enough pull on the ship to provide about 20 percent of the engine power required for the journey.
"We can once again actually 'sail' with cargo ships, thus opening a new chapter in the history of commercial shipping," said Capt. Lutz Heldt following his return.
Larger, more powerful kites are planned for the future. Savings of 10 to 35 percent will be possible, depending on specific routes and weather conditions, says Stephen Wrage, founder and CEO of SkySails, a company in Hamburg, Germany, that makes the kites. It is planning to equip as many as 35 ships with its kites in 2009 and hopes to increase that to 1,500 ships by 2015.
From kites to new propeller designs to blasting air bubbles along hulls to make them slicker, ways to make ships more energy-efficient have been gaining momentum. The reasons aren't surprising: Fuel costs have ballooned and public pressure to reduce the air pollution and greenhouse gases that ships emit has increased.
A scientific paper published in November showed that ship emissions result in about 60,000 additional deaths per year worldwide from air-pollution-related illnesses.
Cargo shipping is growing briskly, by about 5 percent a year, according to a 2007 study by the International Council on Clean Transportation. Air pollutants from oceangoing vessels include nitrogen oxide (NOx), sulfur oxides (SOx), and particulate matter, all of which have been linked to various health problems.
Ship emissions of carbon dioxide (CO2), a greenhouse gas that contributes to global warming, make up about 4.5 percent of total global CO2 emissions.
That's more than twice as much as those created by the aviation industry, which has come under heavy public criticism for its emissions, says a report sponsored by some member countries of the International Maritime Organization (IMO).
The report estimates that CO2 emission from oceangoing vessels will increase another 30 percent by 2020 if no action is taken.
The politics of marine fuel
The IMO is the United Nations body responsible for reducing the negative impact of ships on the environment. It's meeting this week to consider tightening standards for ship emissions. Commercial ships are not included in the Kyoto Protocol, the international agreement to cut greenhouse-gas emissions signed by most of the world's major emitters.
"There currently is no international agreement on greenhouse-gas emissions from ships," says Lee Adamson, a spokesman for the IMO. The group is studying CO2 emissions and originally had planned to propose regulations by 2010, but that deadline may be moved up, Mr. Adamson says.
The shipping industry continues to point out that moving freight by cargo ship is the most energy-efficient means of transporting cargo, vastly superior to trucking or rail on a ton-per-mile basis.
But the industry also realizes that changes are coming. The International Association of Independent Tanker Owners, which represents about 70 percent of independent tanker owners, and the Pacific Merchant Shipping Association favor ending the use of bunker fuel (see story, left), which emits a high level of toxic contaminants. Ships would switch to marine diesel oil (MDO), a fuel similar to that used by many trucks, buses, and cars. The cost of MDO, however, is currently about twice that of bunker fuel.
"A lot of companies have already embraced this [changeover to MDO]," says T.L. Garrett, vice president of the Pacific Merchant Shipping Association in San Francisco. "It is a public health issue. The industry is sensitive to that."
All that shipowners ask is for one consistent international standard for emissions that would apply worldwide – a "level playing field," Mr. Garrett says. Currently, ports in California, Canada, and Europe have tried to set their own emissions limits, essentially banning bunker fuel, because the IMO has been seen as moving too slowly.
Any increase in the fuel economy of ships would also cut emissions, so companies now have two motivations for trying new techniques.
Innovative propulsion – through bubbles and ballast tanks
Research has been under way for years using air bubbles blown along hulls or air cavities (recesses in the hull that emit air). Since air creates less drag on a hull than water, the design can save energy. Solar power and even wave action are also being looked at as auxiliary power sources.
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