German company SkySails are developing wind propulsion systems for modern shipping. These systems are large kites similar to those you see powering kite surfers. Their target market includes cargo ships and large motor yachts.
The advantages of the kite system are that it can be flown in clean air well above the surface of the water and because it is tethered to the deck of the ship it doesn’t produce the leaning moment that would be experienced with a similar size sail on a mast.
The planned product range contains towing kite propulsion systems with a of up to 5,000 kW (about 6,800 HP). On annual average fuel costs can be lowered between 10-35% depending on actual wind conditions and actual time deployed. Under optimal wind conditions, fuel consumptions can temporarily be reduced up to 50%.