Wind turbines create electrical energy from the moving force provided by the wind, which is created by temperature differentiations throughout the atmosphere. These temperature differences cause pressure changes that rise and fall due to heat from the sun. Because of this chain, wind is considered an indirect solar energy, renewable and environmentally friendly.
Wind turbines work in a similar fashion to traditional wind mills. Just like the mills use wind to turn blades that in turn move wheels that grind grain, wind turbines use the same force to turn a rotor that operates a generator that produces electricity. This turns kinetic energy (from the wind) into mechanical movement (the rotor blades and rotating shaft), which creates electrical energy.
When the turbine blades turn, they rotate a low-speed shaft that is connected to a gear. This gear turns a smaller speed shaft that has a tighter rotation with greater torque, essentially concentrating the energy so it can move the rotor at much higher speeds than the wind moves the blades. This rotor is the primary moving part of the generator, which creates electromagnetic energy through a simple induction process. This process works by moving magnetic fields created by copper wire wound around a metal core, a common electromagnetic device. As the coils are turned and the magnetic fields shift, they create a charge that is then channelled in cables, creating a flow of electricity.
There are several peripheral devices included in the turbine that add extra features. An anemometer measures wind speed and digitally stores the information in the controller, which is a device at the base of the generator that turns the wind generator on when the wind speed reaches a certain level, and turns it off when wind speed becomes too high for the turbine to operate safely. This is complemented by a yaw drive and yaw motor in the tower of the wind turbine, which automatically turn the blades to face into the wind.
This process can produce 100 kilowatts to several megawatts of electrical power, depending on size and efficiency. To increase power output, wind turbines are placed in areas with frequent wind that blows primarily in one direction. Ocean-located wind farms are a popular choice because the ocean is more favourable to winds and the farms do not take up land that could be used for other purposes.
There are several types of wind turbines, based on the shape and number of the blades. Some blades are shaped specifically to harness the most wind power available, while others are created based on economical reasons with the materials that are easily available. Many lighter windpower turbines set in large wind farms use a three-blade configuration.