Wind energy is the energy that comes from wind power, and it represents a conventional renewable energy source. It is used for mechanical energy for centuries, and also for electricity generation in recent times. However, the production of electricity in large quantities from wind power was started after the oil crisis in 1973.
Wind energy is renewable and clean source of energy that does not pollute the air, does not emit CO2 and it doesn’t cause acid rain. In addition, there is no radiation and ozone depletion. Also, the use of wind power does not cause undesirable waste. So, this is one of the most environmentally friendly sources of energy.
Today, wind power is mostly used to generate electricity – wind kinetic energy is converted into mechanical energy, and in the next transformation into electricity. Wind energy proved to be the most serious renewable energy source in the achieved technology development. The main reasons for this are:
- Immeasurable amount of energy
- The fall in prices of wind generators and related equipment
- Completely environmentally clean way of energy converting
- Wind farms cover a small land area
Modern wind turbines generate electricity at a wind speed of only 2.5 m / s, and they usually stop (for security reasons) when the wind speed reaches 25 m / s. Economic viability of building wind farms is at a minimum annual wind speed of 4.9 to 5.8 m / s. Due to the friction between air and soil, as well as internal viscous friction, wind speed increases with increasing height above the ground. Wind energy is based on the movement of air (the kinetic energy of air masses), which is located at a height of up to 150 m from the ground.
It is clear that the wind power depends on the roughness of the terrain, the presence of natural and man-made obstacles and other topographical elements. Most widely used wind turbines for wind farms have a capacity of 500 kW to 3 MW. However, where there are favorable natural conditions for strong winds, modern wind farms can have a greater capacity of 5 megawatts.
The wind farm is actually a group of wind turbines that are located in the same area used for the conversion of wind energy into electricity. A big wind farm can consist of hundreds of individual wind turbines in the same location, and the land between the wind turbines can be used for agriculture or some other purpose. All modern turbines have a similar design – a horizontal wind turbine having a rotor with three propellers (blades) that rotates towards the wind direction using a special sensor-mechanical system.
Depending on the location, there are onshore and offshore wind farms. Many of the largest onshore wind farms are located in the China and the United States. These are some of the largest onshore wind farms in the world:
- Gansu Wind Farm – current capacity 6,00 MW, in China
- Alta (Oak Creek-Mojave) – current capacity 1,32 MW, in United States (California)
- Jaisalmer Wind Park – current capacity 1,064 MW, in India
- Shepherds Flat Wind Farm – current capacity 845 MW, in US
- Roscoe Wind Farm – current capacity 782 MW, in US
Wind energy offers great opportunities for further development. Electricity production from wind power has increased significantly in recent years. The production is the most profitable in areas with higher wind speeds, as well as on the coast and the like.