Energetica India Magazine -October 2020

WIND POWER Energy Kites With a simple idea of energy kites, it might be possible to produce enough wind energy anywhere around the clock. However, the engineering required to realize this vision is still very much a work in progress on different aspects. Natural availability of free and abundance wind energy has always fascinated and encouraged human beings for its use in various applications. The basic princi- ple on which the wind turbines work is to convert the kinetic energy in the wind into mechanical power and this mechan- ical power can thus be used for specific tasks or can be converted into electrici- ty using a generator. With the changing scenario towards human dependence on electric energy, efforts have been direct- ed to convert wind energy into electrical energy which has led to the development of wind energy mills and their deployment in the form of wind farms in general and in coastal areas in particular. Wind farms could not get desired response of ac- ceptability from masses due to reasons of like, low efficiency, cost intensive, sound pollution, loss of useful land resources as well as confinement to specific locations. People have always associated the avail- ability of strong wing power as a function of altitude, latitude and direction. There- fore, in order to overcome all limitations associated with wind energy utilization at the ground level and to exploit its avail- ability as function of altitude, latitude and direction, scientists and engineers have come forward with a fascinating idea of energy kites as an innovation to harness maximum wing power overcoming the lo- cational hindrances with a possibility to go anywhere and everywhere where con- ventional wind turbines cannot go. Technology concept with advantages With all focus on the use of renewable energy sources to save the environment as well as to meet the growing demands of energy, wind power is one of the fast- est-growing power sources in the world. So far, the bulk of this growth has been in the form of conventional wind turbines, which are rigid systems with rather lim- ited manoeuvrability. Although modern wind mills/turbines can be downwind tracked around the turbine’s vertical axis which means that only a small part of the available wind energy can be harvested. To increase efficiency, wind turbines must be huge in size, and the bigger the de- vice, the bigger the rotor blades needed. The machines must get bigger for anoth- er reason as well: at higher attitudes they encounter stronger and steadier wind regimes. High altitude winds represent an untapped energy source that is even larger than the world’s energy needs. The structure of a wind tower determines most of its cost and thus imposes a limit to the level of elevation that can be reached but there is another way to harness the avail- able wind power in the troposphere by using energy kites. With the idea of en- ergy kites, instead of harvesting wind en- ergy near the Earth’s surface, where the winds are volatile and the wind speed is low, researchers are looking to go where the wind is blowing constantly and the wind speed is much higher, i.e., several hundred or even several thousands of meters above ground. Harvesting wind energy with the help of energy kites, will enable more peo- ple around the world to have access to clean, affordable wind power. The energy kites fly autonomously in loops, rotors on the wing spin as the wind moves through them, generating electricity that is sent down the tether to the grid. Energy kites use a wing tethered to a ground station to efficiently harness energy from the wind having eight rotors on the kite to function much like the blades on a wind turbine. As the craft flies across the air, the ro - tors drive a generator which will produce electricity. The rotors on the energy kite function like the blades of a wind turbine, driving a generator to produce electricity. Narrow bands of exceedingly high speed winds are known to exist in the higher lev- els of the atmosphere at altitudes ranging from 20,000 to 40,000 feet or more and they are known as jet streams. Energy kite system has three main advantages in comparison to conventional ground wing energy mills/turbines as: reaching to higher altitudes, use of less materials, and more aerodynamically effective. The ground station of an energy kite will also need considerably less ground space than a conventional wind turbine. Entre- preneurs believe that energy kites offer untapped opportunities to harness winds high above the earth and generate elec- tricity at a lower cost than the wind tur- bines. Microsoft founder Bill Gates has said that there is a chance that energy kite technology could provide a “magic solution” to some of the world’s energy needs. Developmental Status • The energy kite technology has got a boost towards commercialisation after Kite Power Systems (KPS), a British start- up, received an investment from three Dr. S. S. VERMA Department of Physics, S.L.I.E.T. 44 energetica INDIA- October_2020