A German company Sky Sails is helping shipping companies power their ships with the aid of a huge kite.  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

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.

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.   The kite sail will help reduce annual fuel costs by 10-35%. Reduced fuel also means fewer harmful carbon emissions