Current wind power generation relies on rigid supporting structures and is limited to altitudes up to 200 m. Wind at higher altitudes is significantly stronger and more persistent. To access this major potential of renewable energy, the Kite Power research group is developing a technology based on inflatable membrane wings which are tethered to a motor/generator unit on the ground. The present kite power demonstrator system operates kites of 14, 25 or 50 m2 surface area in periodic pumping mode to generate 20 kW mechanical reel-out power. Systematic testing and improvement has resulted in more than 160 completed pumping cycles since January 2010, indicating a continuous increase in cycle efficiency.
Supporting research is addressing scientific challenges such as automatic flight control, structural dynamics and aerodynamics of tethered inflatable membrane wings. This includes development of physical models ranging from fast, real-time capable point mass or rigid body models up to accurate analysis tools based on Multi-Body or Finite Element discretisations. A second focal area is the design of efficient motor/generator units. Research into kite power generation was initiated by Wubbo Ockels in 1993, followed by a patent application for the laddermill technology in 1997. The research group has been established in 2005 and presently comprises 7 staff members and a similar number of MSc students. Airborne Wind Energy is the subject of two MSc-level courses at the Delft University of Technology, “Kite Power Generation & Propulsion” and “Wind Power”, both having attracted more than 70 students in 2010.