In their search for innovative technologies that can harness energy from renewable sources, a team of scientists from University of Delft, The Netherlands, has tested the use of kites as a substitute to conventional wind turbines.
Roland Schmehl, an associate professor in computational fluid dynamics, and his research group, believe that wind as an energy resource is not fully exploited. One of the main limitations that the team outlines is that wind turbines operate at low height. The higher in the atmosphere the wind power generator is located, the more likely it is that a continuous wind blow is reached.
Based on this, the scientists looked into developing the kite technology. Preliminary tests indicated that a 25 square meter sail can generate enough energy to power as many as 40 households. This is achieved by connecting the device to a ground-based generator unit. The better the generator module and the flight dynamics of the kite are synchronized, the more energy is produced.
The process consists of two cycles- the reel-out and the reel-in of the connecting cable. During the first cycle, energy is generated by conversion of the traction force created as the kite flies. When the maximum extend of the cable is reached, the kite is de-powered and let to align naturally with the apparent wind. Then, an automatic controller and the drum/generator module on the ground, pull the kite back to its initial position to repeat the cycle.
According to Schmehl, a large scale production process using the technology should cut down the cost of wind energy from eight down to two cents per kilowatt hour. The only limitation that the team foresees, is the fact that kites fly at heights that might interfere with regular aerial traffic and flight routes in Europe. This is also a reason why the scientists are now looking into possible use of the electricity generating kites in the rural areas of Africa.
Interestingly, companies and governmental organizations around the world are also looking for ways to use the constant wind flow at greater heights by developing various airborne wind technologies.