WIND IS ALSO AN ANTERNATE SOURCE OF ENERGY

WIND TURBINE POWER GENERATION

                

              Wind power is achieved from flow of air using windmills or wind turbines to produce mechanical to electrical energy. Windmills are used for their mechanical power, wind pumps for water pumping, and sails to propel ships. Wind power is one of the alternative to fossil fuels, it is free of cost, renewable, clean, produces no greenhouse gas emitted during operation. The actual effects on the environment are very minimal as compared to other non renewable sources of energy.

                In a wind farm there are many individual windmill/wind turbines which are connected to the electrical power transmission network and further connected to the peripheral power house. A basic process of the power generation of wind turbine is given below.

                                                                           Fig 1:-Block diagram representation

Windmill or Wind  Turbine

A windmill is a mill that runs on the energy of wind by means of blades or vanes(i.e. rotational energy). In earlier times, windmills usually were used to mill grain, pump water, etc. After the further development of windmills in modern days the windmills has taken the form of wind turbines used for generating electricity, or wind-pumps used for pumping water, normally for irrigation purpose.

A wind turbine is a device that converts the wind's kinetic energy(by rotation of its blades) into electrical energy.

Wind turbines are manufactured in a wide range of vertical and horizontal axis types as per the method of power generation technique. The smallest turbines are mainly used for charging batteries for auxiliary power for boats or other light vehicles and to power traffic warning lights. Slightly larger turbines can be useful for a domestic power supply and selling excess unused power back to the supplier or other consumers via the electrical grid. Arrays of large turbines are known as wind farms, and it is becoming an important source of clean renewable energy and are adopted by many countries as a part of their strategy to reduce dependency on fossil fuels without compromising in the supply of electricity.

Wind turbines works on a simple principle. The flow of wind turns two or three propeller like blades around a rotor. The rotor is connected to the main shaft, which rotates an alternator/generator to create electricity.

Wind farm or On-shore wind power

A wind farm is a group of wind turbines in the same location used for production of electricity. A large wind farm may consist of several hundred individual wind turbines distributed over an extended area, but the land between the turbines may be used for agricultural or other purposes. For example, Gansu Wind Farm, the largest wind farm in the world, has several thousand turbines. A wind farm may also be located offshore.

Almost all large wind turbines have the same design — a horizontal axis wind turbine having an upwind rotor with three blades, attached to a nacelle on top of a tall tubular tower.

In a wind farm, individual turbines are interconnected with a medium voltage (often 34.5 kV), power collection system and communications network. At a substation, this medium-voltage electric current is increased in voltage with a transformer for connection to the high voltage electric power transmission system.

Off-shore wind power

Offshore wind power refers to the construction of wind farms in large bodies of water to generate electricity. These installations can utilize the more frequent and powerful winds that are available in these locations and have less aesthetic impact on the landscape than land based projects. However, the construction and the maintenance costs are considerably higher.

Siemens and Vestas are the leading turbine suppliers for offshore wind power. DONG Energy, Vattenfall and E.ON are the leading offshore operators. As of October 2010, 3.16 GW of offshore wind power capacity was operational, mainly in Northern Europe. According to BTM Consult, more than 16 GW of additional capacity will be installed before the end of 2014 and the UK and Germany will become the two leading markets. Offshore wind power capacity is expected to reach a total of 75 GW worldwide by 2020, with significant contributions from China and the US.

At the end of 2012, 1,662 turbines at 55 offshore wind farms in 10 European countries are generating 18 TWh, which can power almost five million households. As of August 2013 the London Array in the United Kingdom is the largest offshore wind farm in the world at 630MW. This is followed by Gwynt y Môr (576 MW), also in the UK.

Advantages

i. The wind is free and with modern technology it can be captured efficiently.
ii. Once the wind turbine is built the energy it produces does not cause green house gases or other pollutants.
iii. Although wind turbines can be very tall each takes up only a small plot of land. This means that the land below can still be used. This is especially the case in agricultural areas as farming can still continue.
iv. Many people find wind farms an interesting feature of the landscape.
v. Remote areas that are not connected to the electricity power grid can use wind turbines to produce their own supply.
vi. Wind turbines have a role to play in both the developed and third world.
vii. Wind turbines are available in a range of sizes which means a vast range of people and businesses can use them. Single households to small towns and villages can make good use of range of wind turbines available today.

Disadvantages

i. The strength of the wind is not constant and it varies from zero to storm force. This means that wind turbines do not produce the same amount of electricity all the time. There will be times when they produce no electricity at all.
ii. Many people feel that the countryside should be left untouched, without these large structures being built. The landscape should left in its natural form for everyone to enjoy.
iii. Wind turbines are noisy. Each one can generate the same level of noise as a family car travelling at 70 mph.
iv. Many people see large wind turbines as unsightly structures and not pleasant or interesting to look at. They disfigure the countryside and are generally ugly.
v. When wind turbines are being manufactured some pollution is produced. Therefore wind power does produce some pollution.
vi. Large wind farms are needed to provide entire communities with enough electricity. For example, the largest single turbine available today can only provide enough electricity for 475 homes, when running at full capacity.