Wind Farms for Energy Generation

Sep 9, 2017   //   by admin   //   Knowledge Base  //  No Comments

Wind energy is now towards becoming the main stream energy. The deployment of wind energy has been increased in recent years.

Wind farm is a group of wind turbines which harnesses wind power to generate mechanical power or electricity. Since ancient times wind power is used for many purposes like irrigation, grinding cereals, spices etc. Wind turbines work by transforming the Wind Energy into mechanical power that can be used for conversion to electricity or for other mechanical purposes.

Wind being a perennial source of energy can be used for powering home and businesses. The capacity of a wind turbine to produce power depends upon the amount of energy which the wind transfers to the rotor depends on the density of the air, the rotor area, and the wind speed.

Wind turbines can either be installed on shore or off shore. On-shore installations are installations in territorial or land region where as Off Shore installations are setup in water bodies to generate electricity from wind. Wind speed and currents near water bodies have more kinetic energy as compared to land so these are more efficient then “on- shore installations”.

On-shore Wind farms are constructed on land. Alta Wind Energy Center in California is the largest onshore wind farms outside of China, with a capacity of 1020 MW of power. These have some advantages over Off Shore installations. These have cheaper foundations, low cost integration with the electrical-grid network, cheaper installation and access during initial construction phase and easier access for operation and maintenance. But these are subject to certain restrictions like heavy noise, land disputes and visual environmental impacts.

Off Shore wind farms are constructed in water bodies to generate electricity from wind like in lakes, fjords and sheltered coastal areas utilising traditional wind technologies as well as deep sea using floating wind turbines. Walney Wind Farm in United Kingdom is the largest Off Shore wind farm with 367 MW capacity of power Thanet Offshore Wind Project with 300 MW that too in UK. Offshore wind power can help to reduce energy imports, reduce air pollution and greenhouse gases (by displacing fossil-fuel power generation), meet renewable electricity standards, and create jobs and local business opportunities. However, off shore wind farms are more expensive then On-shore installations.

The Capacity factor of a wind turbine (i.e. the ratio of actual productivity in a year to this theoretical maximum) depends upon three factors:-

  • of blades
  • Size of Generators
  • Speed of wind

The efficiency of a wind turbine largely depends upon the no. of blades in the turbine. Rotors with an odd number of rotor blades (atleast 3 blades) can be are considered to be stable and are similar to a disc. While a rotor with an even number of blades will give stability problems for a machine with a stiff structure. The reason is that at the very moment when the uppermost blade bends backwards, because it gets the maximum power from the wind, the lowermost blade passes into the wind shade in front of the tower.

Generators play an important role in power generation. Usually Inductions Generators are used for wind mills due to their ability to produce useful power at varying rotor speeds. They are attached at one end to the turbine, while the other end is connected to the power grid. Different types of generators behave differently during grid transmissions. Small generators are less efficient and require less force to turn than larger ones and are cheaper, but gives lower power output. Large Generators are very efficient at high wind speeds, but unable to turn at low wind speeds and are expensive.

The speed of wind is not predictable and is variable. Hence, the output and the electricity generated can also be variable seasonally. The weather forecasting methods are used but still the productivity of wind turbines in short term can vary more or less than 10%.

Advantages of power generation from wind farms :-

  • It is eco-friendly source of energy as there is no emission of toxic gases.
  • Though speed of wind is variable but still it is a dependable source of energy as it won’t expire ever.
  • Wind farms usually don’t require much land space as compared to other power stations. And also the space between wind turbines can be used for farming purposes and cattle grazing.
  • If harnessed properly their efficiency can be increased up to 10% more than present efficiency.
  • It can be accessed by off – grid remote areas where it is expensive and difficult to run electrical lines.

 

Disadvantages of Wind Farms:-

  • Even though cost of production of electricity decreased during past few years still it requires high initial investment.
  • Noise creation by wind turbines.
  • Birds and bats often collide with rotors and blades.
  • The major challenge of using wind power is its variability and intermittency. It can’t be predicted.

Summing up all the advantages and disadvantages of using wind power. We can say that Wind power have a bright scope of its future as renewable energy and its disadvantages can be eradicated by technological advancements.

 

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