How Do Wind Turbines Work?

Did you know that wind generates enough kinetic energy to produce 35 times the amount of electricity humanity uses in a day!

This means that if we managed to harvest just a fraction of the wind kinetic energy that is out there, we would have all the power we need and more.

But how can we harvest this amazing energy to power our homes?

The answer is pretty simple: by using wind turbines.

In this article, we will show you exactly how wind turbines work even if you don’t have any previous knowledge about them.

The Internal Components of Wind Turbines

Before getting into how wind turbines exactly work, first, let’s take a look at their main parts.

A wind turbine consists mainly of six parts:

  • Blades
  • Wind Vane
  • Gearbox
  • Brake
  • Generator
  • Tower

Each one of these components has a vital role to play in the generation of electricity from wind power.

In this section, we will explain each part separately while highlighting how they work & interact together to produce energy.

Blades

wind turbine blades
Wind turbine blades (Creative Commons CC0)

The first, and most important part of the wind turbine is the blades.

For typical wind turbines, each of the three blades has an average length of 80 to 85 ft (24 m to 26 m) and weighs around 5200 lb (2360 kgs).

This makes it difficult to imagine how normal wind can cause them to move!

Well, it’s all about the aerodynamic design of those blades. 

They’re built in such a manner that when the wind blows perpendicular to the blades, a force is produced, causing them to rotate.

This force is the sum of two aerodynamic forces: drag and lift.

Drag is a pulling force applied in the same direction of the relative flow (behind the blades), while lift is a pushing force applied perpendicular to the relative flow (under the blades).

Lift and drag force of wind turbine airfoil
The effect of lift and drag forces on wind turbine’s blades (Creative Commons CC0)

In simple terms, the wind turbine’s blades are made with an airfoil design similar to the one used in airplanes.

When air passes under the blade, it gets deflected down, at the same time, the air above the blade is guided along its surface and down as well.

And since the wind is deflected down, it creates a force (drag and lift) that pushes the blade up, thus causing it to rotate.

Wind Vane

weather vane in wind turbines
Weather vane (Creative Commons CC0)

A wind vane, or weather vane, is a tool used for determining the direction of the wind and it was probably one of the first weather instruments ever.

It has two parts or ends: 

One that is usually arrow-shaped and contracts into the wind, and another which is broader and picks up the breeze.

To determine wind direction, a wind vane spins and points in the direction of the incoming wind.

If it is pointing east, for example, that means the wind is blowing from the east, and so on.

So, what is the importance of the wind vane?

Well, wind turbines produce maximum electricity when the blades spin faster and this happens when the blades are perpendicular to the wind direction.

Therefore, to increase the output efficiency, a mechanism is used to rotate the head of the turbine, so it can always face the wind.

The wind vane’s job is to provide this mechanism with the wind direction, so it can yaw the head with the exact angle that ensures maximum output.

Gearbox

 

Wind turbine's gearbox
Picture of a wind turbine’s gearbox By Paul Anderson, CC BY-SA 2.0, Link

As we mentioned earlier, the blades are really heavy.

While the airfoil design helps the blades to rotate, the RPM (revolutions per minute) achieved by them are usually not sufficient for the rotor to produce energy.

Here comes the gearbox’s role.

The gearbox works by converting the low rotational speed of the propeller into high rotational speeds for use by other elements.

Typically, the blades complete 30–60 RPM, and with the help of the gearbox, this number will be increased 90 times! 

Brakes

Brakes on wind turbines
Brakes on a 100kw wind turbine by MARTIN BROWN (Creative Commons CC0)

Wind turbines are subject to sudden changes in wind speed.

These rotational speeds should not exceed a certain limit for obvious reasons.

Here comes the brake’s job. Bakes are used to stop the rotor from spinning during high wind speeds to prevent any overloads on the internal components of the nacelle. 

Generally, you can say that blade braking systems are installed to protect the system during emergencies.

Generator

Wind turbine generator
Photo of a wind turbine generator (Creative Commons CC0)

The generator is a crucial component of the whole wind turbine system. After all, it’s the one responsible for transforming the kinetic energy into electricity.

It primarily consists of a number of gears that are connected together to increase the total RPM, which is why some turbines are equipped with more than one gearbox.

Obviously, the generator’s main job is to generate electrical power by converting kinetic energy (achieved through high RPMs) into electricity.

Tower

Finally, a wind turbine’s tower supports the whole structure of the turbine.

The huge size of the wind turbine isn’t only to support the weight of the blades, in fact, it also affects the level of power production.

As you know, wind travels much faster at higher elevations.

This means that the taller the tower, the better a wind turbine’s ability to capture faster wind which will, in turn, increase the RPM of the blades and boost electricity production.

Fun fact: The world’s tallest existing wind turbine is in the German town of Gaildorf, near Stuttgart, with a total height of 246.5m.

The growing size of wind turbines over the past 20 years
The growing size of wind turbines over the past 20 years By Heinrich-Böll-Stiftung – https://www.flickr.com/photos/boellstiftung/26614518499/in/album-72157632531168908/, CC BY-SA 2.0, Link

How A Wind Turbine Works Step By Step

  1. The wind turbine is located on top of a tall tower, where it catches the fast wind
  2. After a wind turbine is skewed to face the wind, the turbulence caused by the difference in air pressure in front and behind the blades causes the blades to rotate, which in turn rotates the low shaft inside the wind turbine’s nacelle
  3. The gearbox connected to the low-speed shaft then increases the RPM by 80-100 times and feeds it to the generator via the high-speed shaft
  4. The generator uses this kinetic energy and converts it into a form of electricity
  5. The generated electricity travels down a wire to an inverter, where it is converted to usable alternating current and sent to the power grid
  6. Finally, the utility provider will distribute this energy to homes, factories, and other facilities

Last Words

Wind energy is the most abundant source of renewable energy.

By using this clean and free resource, we can reduce CO2 emissions that damage our environment and help to fight global warming.

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