Wind turbines are a familiar sight in many countries across the globe, but have you ever wondered how wind turbines work? This article will help you understand the different components of a wind turbine and how they come together in order to convert wind energy into electricity.
A wind turbine is essentially an electric fan only in reverse. Instead of using electricity to produce wind, a wind turbine uses the wind in order to produce electricity.
When the wind is strong enough, it has enough energy to rotate the blades of a wind turbine. A wind turbines blades are connected to an electrical generator with the help of a low speed shaft, a gearbox and a high speed shaft.
The Different Components of a Wind Turbine
There are numerous components of a wind turbine, some you will be able to visibly see and others that are hidden away inside the turbines nacelle (casing.)
A wind turbine has a number of components that are visible from the outside. The purpose of each of these components can be found below.
One of the most notable components of a wind turbine is its tower. It’s common to find wind turbines with a tower that is over 200 feet tall. This doesn’t take into account the height of the blades which can easily add another 100 feet to the overall height of a wind turbine.
The tower contains a ladder for maintenance crews to access the top of the turbine and will also contain high voltage cables for transporting the electricity produced by the generator at the top of the turbine to its base.
On top of the tower you will notice the nacelle which is the streamlined casing that houses a wind turbines internal components. The nacelle has the appearance of a large rectangular box and is sat directly on top of the tower.
The nacelle provides protection from the elements for vital internal components of a wind turbine. These components will include the generator, gearbox and low and high speed shafts.
Arguably the most noticeable component of a wind turbine is its blades. A wind turbines blades can be over 100 feet in length and you will often find three blades fitted to a commercial wind turbine, making up the rotor.
The blades of a wind turbine are designed to be aerodynamic so that they are able to harness wind energy more easily. When the wind blows, a wind turbines blades will begin to turn, creating the kinetic energy that is required to produce electricity inside the generator.
Anemometer & Wind Vane
Other external components of a wind turbine include the anemometer and the wind vane. It’s unusual to be able to spot these on a commercial wind turbine due to their relatively small size in comparison to the turbine.
The anemometer and wind vane are often fitted to the rear of the nacelle and are used to measure the current wind speed and direction. This data can then be fed to a wind turbines internal control system which can then adjust the yaw of the turbine and the pitch of its blades in order to maximise its efficiency. It should be noted that not all commercial wind turbines will feature a yaw and pitch mechanism.
A wind turbine has a number of components that are hidden from view inside the nacelle. The purpose of each of these components can be found below.
Low Speed Shaft
The low speed shaft is turned by the motion of a wind turbines blades as they rotate. The low speed shaft transfers kinetic energy to the gearbox.
The gearbox is a heavy and expensive piece of equipment that connects the low speed shaft to the high speed shaft. The purpose of the gearbox is to increase rotational speeds to a level that is sufficient for a generator to produce electricity.
High Speed Shaft
The high speed shaft connects the gearbox to the generator and its sole purpose is to drive the generator so that it can produce electricity.
The generator is driven by the high speed shaft and will produce electricity when enough kinetic energy is being delivered by the shaft.
Pitch & Yaw Motors
Some wind turbines feature pitch and yaw motors to help maximise a wind turbines efficiency by positioning the blades in the best possible direction and at the best possible angle.
A pitch motor is often found near the hub of the rotor and will help to angle the blades to provide better aerodynamics. The yaw motor will be found inside the tower underneath the nacelle and will turn the nacelle and the rotor to face the current wind direction.
A crucial component of a wind turbine is its brake system. This is designed to prevent a wind turbines blades from turning too quickly, which could in turn damage its components. When the brake is applied, some of the kinetic energy will be converted to heat.
Commercial wind turbines will feature an internal control system that has a number of uses. It has the ability to start the wind turbine when wind speeds are high enough and can also shut down the turbine when wind speeds are too high.
The control system is also the mechanism that will calculate the most efficient pitch and yaw for the turbine dependant on wind speed and direction.
How Wind Turbines Generate Electricity
Now that we have a good understanding of the components that make up a wind turbine, we can take a look at how wind turbines work in order to generate electricity. This process is as follows:
- The process is kicked off by a turbines blades/rotor. As the wind blows, the aerodynamic design of the blades will harness some of the winds energy and will begin to turn.
- As the blades of a wind turbine rotate, the kinetic energy of this motion is transferred to the inside of the turbine with the help of the low speed shaft which will turn at about 30 to 60 rpm.
- The low speed shaft is connected to the gearbox, a device that is responsible for increasing the rotational speed from around 30 to 60 rpm to a speed that is required by the generator (commonly between 1,000 and 1,800 rpm.)
- The high speed shaft will transfer the kinetic energy from the gearbox to the generator which will then begin to turn, producing electricity.
- Electricity will then be fed down the tower of the turbine via a high voltage cable and will often be fed to a national electricity supply or used as a local power source.