SkySails Group GmbH is a successor company to SkySails GmbH, which was founded in 2001 by Stephan Wrage and Thomas Meyer in Hamburg.
The company, while technically successful at cutting shipping costs and carbon emissions, has faced economic difficulties. Head of business development Henning Kuehl has said:
There's a structural problem slowing down the process: ship owners (who have to make the investment) often don't pay for the fuel – that's the charterer's duty. The charterer on the other side doesn't charter the ship for long enough a period to make low-carbon technologies pay back.
The lack of carbon emissions regulations for shipping and low fuel prices have added to these difficulties.
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In the weak economy of 2012, a time of low investment by shipping companies, the company laid off half of its 80 employees. On March 7, 2016, SkySails GmbH, as part of the SkySails Group, was forced to file for insolvency and was dissolved on April 5, 2016. Since then, SkySails Group GmbH, as the successor company, has continued business operations and has developed a further business area in the form of the SkySails Power division.
The company's headquarters are in Hamburg. The assembly of ground stations of the airborne wind energy systems takes place in Lower-Saxony.
Technology
The SkySails propulsion system consists of an automatically controlled foil kite of some hundreds of square meters, an electronic control system for the kite, and an automatic system to retract the kite.
The ram-air kite, while 1-2 orders of magnitude larger, bears similarities to the arc kites used in kitesurfing. For multiple reasons, ram-air kites give many times the thrust per unit area of conventional mast-mounted sails. Additionally, a control pod is used rather than direct tension on multiple kite control lines; only one line runs the full distance from kite to ship, with the bridle lines running from kite to control pod. Power to the pod is provided by cables embedded in the line; the same line also carries commands to the control pod from the ship.
The kite is launched and recovered by an animated mast or arm, which grips the kite by its leading edge. The mast also inflates and deflates the kite. When not in use, mast and deflated kite fold away.
A conventional ship with a SkySails system burns less fuel, and has two propulsion methods, making it a type of hybrid vehicle. SkySails' kite propulsion from upper wind power is a traction use of high altitude wind power. Up to 100 million tons of carbon emissions every year could be saved by widespread use of SkySails technology, according to the International Maritime Organization.
Other companies, such as California-based KiteShip, have built similar technology.
Technology
Driven by the wind, the automatically controlled power kite rises in figures of eight. As it gains altitude, it unwinds a tether from a winch on the ground. The tractive force drives a generator inside the winch that produces electricity. Once the tether has reached its maximum extension of 800 meters, the autopilot steers the kite into a neutral position with minimal drag and lift. While consuming only a fraction of the energy generated before, the generator now acts as a motor and reels-in the tether. The system continuously repeats this process, flying the kite at an altitude of 200 to 400 meters. Energy generated by the Airborne Wind Energy System can be fed into the grid, stored in batteries, or directly consumed.
