Sail power is back.
The MV Beluga SkySails, a cargo ship rigged up with a billowing 160-meter sail from SkySails, used approximately 20 percent less fuel than it would have without the sail during a two-month voyage. Put another way, that's 2.5 tons of fuel, or $1,000 a day, in operating costs. Beluga Shipping ultimately hopes to save $2,000 a day with the technology.
The ship left Bremen, Germany, on the 22nd of January, sailed to Venezuela, and then headed toward the Norwegian port of Mo-I-Rana, docking on March 13. In all, the ship sailed 11,952 nautical miles. The sail was up, depending on the winds, from between 5 minutes and 8 hours a day.

In the picture, look in the sky past the end of the ship. That's the sail up there. The sail is attached to a tether that runs 100 to 300 meters long. This is an actual shot from the ship--until now, the company has had to use artists' renderings.
The company says that the sail, by their calculation, could cut fuel consumption by 10 to 35 percent on ocean voyages, depending on the conditions, the size of the ship, and other factors. More testing will be conducted this year. SkySails will double the size of the sails and attach them to larger, heavier ships. A big question will be how well the economics--buying a sail versus using diesel--work.
Other companies working on reducing emissions and fuel consumptions on ships include Solar Sailor, which has created sails with integrated solar panels. A ferry with the sails already prowls Sydney Harbor. San Francisco may get one in 2009.