Global demand for green and sustainable energy is ever rising. Scientists are tapping all the possible sources of renewable energy available on the earth. Many creative and innovative concepts are being implemented. Researchers have always eyed on the new developments in the wind energy technology. As per the Greenpeace International and the Global Wind Energy Council, wind turbines are expected to account for 12% of the overall electricity generation worldwide by 2020.
One of such novel technology of producing electricity from renewable resources is the new type of wind energy converters named as Airborne Wind Energy Systems (AWESs). The market for AWEs is going to be directly proportional to the rising demand for the green energy.
An airborne wind turbine is a very novel concept. These AWESs have been conceived to harvest the wind energy at high altitudes. Though the basic research had started in the late seventies, it actually was rapidly accelerated in the last decade. Quite a few systems based on radically different concepts have been analysed and simulated at the design stage. Several prototypes are developed all over the world and the results from the experiments are very encouraging.
In the Airborne Wind Energy Systems, the rotor of a wind turbine is suspended in air without the support of a tower. Actually, weight and cost of the tower supporting the rotor in present wind turbines is one of the major factors which stimulated scientists of AWESs. This unique innovative design of the wind turbine offers aerodynamic and mechanical benefits. This new generation of systems makes use of flying tethered wings or aircraft, to reach winds blowing at atmosphere layers which are not accessible by traditional wind turbines. These turbines curb the need for devices such as slip rings and reduce the spending and time on tower construction and yaw mechanisms; they offer very high velocity and greater efficiency at higher altitudes.
The idea of suspending a heavy rotor in the air to produce electricity looks weird. But in a lay man’s language, this can be very easily explained – a kite generating electricity. We fly a kite; it catches the wind energy and transmits it to earth either by the onboard generators or by pulling cables that act on a ground-based generator. There has been a lot of criticism about this when the research started, but the prototypes are proving all these critics wrong. And AWESs are most likely to produce electricity commercially in future.