Smoother sailing on kite-and-diesel hybrid ships

From sails to steam to diesel – and back to sails. That’s what some innovative shipping companies advocate to clean up the polluting cocktail of smokestack spew from tankers and yachts. As a proof of concept, this week the MV Beluga SkySails, a ship outfitted with a 160-square-meter kite, finished a breezy voyage from Germany to Venezuela, the United States and Norway, powered in part by wind across 11,952 nautical miles.

The Beluga SkySails system uses software that charts a course to find the best wind conditions, and compressed air to change the angle of the kite to match different wind speeds and weather. The European Union-funded company’s chief executive expects to see fuel savings of 10 to 35 percent using wind power, depending on the route. To achieve further increases, the company expects to move to a larger sail of about 320 square meters later in 2008.

Kites are more than just a gimmick; simple as they may be, they’re a legitimate avenue of research, along with investigations into speed reductions, the potential to switch to less harmful fuels from diesel, and the elimination of drag. For example, in 2005 a shipping company unveiled its “concept car carrier” – alas, not the platform upon which all concept cars are shuttled around to motor shows, but rather a zero-emissions, solar/wind/fuel-cell-powered tanker called the E/S Orcelle. But before that vessel makes it out into the open waters, we’ll more likely see ships run on gas, probably with sleeker profiles and improvements in propeller design. Consider, for example, a company called PAX Scientific that designs biomimetic, spiral-shaped turbines that could help ships cut through water more smoothly, improving their fuel efficiency by about 10 percent.

It remains to be seen whether retrofitting sails to tankers will catch on, but Skysails estimates the potential upgrade market for its system at more than 40,000 ships. Through 2013, Skysails is targeting less than 1% of that market—about 400 ships.

A key part of the success of sails will depend on incorporating satellite predictions and long-range weather forecasts to help chart courses that are energy-efficient without sacrificing much on speed. Past efforts to launch kite-based ship propulsion have floundered due to the unpredictability of wind conditions.

And there’s definitely room for improvement in long-distance shipping. A 2003 University of Delaware study found that the world shipping fleet consumes about 289 million tons of fuel each year, of course accompanied by a gargantuan emissions profile. According to Geotimes, “the world’s fleet of cargo ships, fueled by refinery leftovers — black sludge that’s cheaper and thicker than crude oil — emits more carbon dioxide than the world’s fleet of airplanes.”