For an emerging country like India it is essential that electricity is generated in large quantities. The conventional methods are either by use of thermal or hydro sources. India generates approximately 80% by thermal and 15% by hydro means. Rest is by non conventional means like solar,wind and biomass sources.
India is a large country with an equally long coast line. One of the nonconventional or renewable sources amply available is wind energy. It is free of cost and non polluting which is a great boon in these days of environment awareness.
How is wind energy converted into electricity? A wind turbine is adevice that converts kinetic energy from the wind into electrical power. It is done by running a turbine mounted on a tower. The turbine blades, 2 or 3 in number rotate because wind creates a lift on the rotor blades ,like it does in case of aircraft wings.. They rotate a shaft which through a gear assembly runs a smaller shaft which runs the turbine generating electrical energy. The few revolutions per minute of the rotor shaft are covered into many more revolutions per minute of the turbine via the gear assembly. The generated electricity is sent to a transformer which adjusts the voltage and it is then fed into the electric grid for onward transmission.
The speed of the wind is important as on it depends the volume of power that can be generated. Generally the rotor blades start rotating at 4 meter per second wind speed. If the wind speed reaches 25 meter per second it is considered as optimum. A wind turbine is not operated at higher wind speeds because it can damage the turbine.
The speed of the wind depends on the air density. Higher density exerts higher lift on the rotor blades and higher revolutions can be achieved.It results in higher power generation.This is the main reason why wind turbines are located near to coastal locations.This is called onshore location. The air density over sea surface is still higher and it can create more powerful lifts which can impart higher rotation to rotor blades and can generate still higher electricity. Increasing number of wind turbines are now being located offshore inside the sea. Also the diameter of the blades also plays an important role in power generation. Present diameters are around 50-60 meters but a 120 meter diameter assembly is made by a famous power equipment manufacturer and installed
As stated earlier wind energy is non-polluting but the rotors make noise while running and this can cause nuisance to nearby residents. However it is still not a big issue because wind turbines are usually located in remote coastal locations away from residential areas. Also the local asthetics tends to get disturbed by the location of a large number of wind towers supporting the turbines.
In India Tamil Nadu was the pioneering state to launch wind energy project in the early nineties and has today installed around 7,000 MW. It continues to be number one today also, followed b Gujarat(3,000 MW), Maharashtra(2,900 MW), and Karnataka(2,100 MW) all coastal states. Mp, Rajasthan, AP, Kerala,Orissa and W Bengal are also now active.Wind power accounts for nearly 8.5% of India's total installed power capacity and generates 1.6% of country's power.
The worldwide major installed capacity by the end of 2012, was in China (75,564 MW), US (60,007 MW), Germany (31,332 MW) and Spain (22,796 MW) out of a total of 2,82,000 MW global capacity.. The short gestation periods for installing wind turbines and their increasing reliability and performance of wind energy machines has made wind power a favoured choice for capacity addition in India.
The Indian government has announced a revised estimation of the potential wind resource in India from 49,130 MW assessed at 50 meter tower heights to 1,02,788 MW assessed at 80 meter tower heights.
Most of the commercial-scale turbines installed today are 2 MW in size and cost roughly $3-$4 million installed.Oftentimes there are tax and other incentives that can dramatically reduce the cost of a wind project.
India and many other countries especially in the European Union are trying to increasingly harness wind energy to generate power. This will help in reducing import of fosssil fuels and also reduce emission of harmful carbon dioxide / carbon monoxide into the atmosphere.
Wind energy needs to be encouraged for its many benefits over conventional sources of energy.