The most common type of wind turbine, it consists of a tall tower with two or three large blades, similar to windmills. The blades are gigantic – usually 60 or 70 meters across. The tower is usually 85 meters off the ground, because the higher you are, the greater the wind. And the whole structure is just a giant 150 meters tall. For comparison, an ordinary nine-story building is only 17 meters tall. Large turbines are the most efficient for generating energy.
The blades are connected to a central shaft, the so-called rotor. The rotor rotates a series of gears that increase the blade’s rotation by 100 times – creating a speed that is convenient for generating electricity by the generator. Therefore, it seems that the blades are always rotating lazily. There is also a computer at the top of the tower that keeps the blades in the best direction.
The key element of the turbine, called the nacelle, sits on top of the tower, behind the blades. The nacelle contains both the gearbox and the generator, which takes the kinetic energy from the rotating rotor shaft and converts it into direct current electrical energy.
The direct current goes down the inside of the tower, where a converter makes the DC into alternating current – the kind we use in our households. The transformer then increases the voltage by about 50 times, so that at a higher voltage, the current can be transmitted more efficiently to the substation, through underground cables. From the substation, electricity is distributed through the grid to consumers in homes and businesses.