Generally, we all know that wind turbines generate electricity using wind power. However, if you were to ask most people how this process works, they’d be confused. This is despite the fact that humans have been using wind power for electricity since the 1800s and to power ships for much longer than that.
The number of wind farms around the world has also grown considerably over the years, along with the development of smaller operations. All in all, wind power will continue to be an essential aspect of humanity’s energy mix going into the future.
Therefore it’s worth asking the question: how do wind turbines work step by step?
How Does a Wind Turbine Work?
Early models of the wind turbine had a slightly different design to what they are today. First of all, they had flat blades that were turned at an angle that was best for maximizing rotation.
Over time, the rotor design evolved to include an airfoil shape that made the blades heavier than air and more efficient overall. Airfoil shaped blades are the standard nowadays when it comes to rotor design.
Another important consideration is blade length because it plays a major role in the turbine blades’ overall performance. Longer blades are often made from lightweight yet durable materials so that they can deliver more torque.
Top speed is another aspect of the rotor design that you have to know if you’re interested in wind turbines. For instance, a rotor that measures 100 meters in diameter will most likely travel at 15 RPM, which means its top speed will be 175 MPH or 4,710 m/min. Although this increases the blades’ efficiency to a point, it also increases the rate of blade erosion and can be a hazard to birdlife. Even the sound that it makes at that speed can be quite annoying. The good news is that research is underway to develop a silent or quieter rotor.
Furthermore, wind turbines are made to have three blades per rotor in order to prevent blade interference and a phenomenon known as the Betz Limit. The Betz Limit happens when the air behind the rotor stops moving because the rotor has extracted all of the kinetic energy in the wind.
Types of Wind Turbines
Wind turbines come in two different designs; namely vertical axis turbines and horizontal axis turbines. Vertical axis wind turbines are characterized by blades that turn parallel to the ground while horizontal axis wind turbine blades rotate perpendicular to the ground.
- Horizontal Axis Wind Turbines
- 500 Watt Max/400 Watt Rated
- Pole not included
- Wind turbines include generator, blades, controller and screws/bolts
- Maintanence free
- Greater energy production yield for all wind speeds and lowest ownership cost
Horizontal axis wind turbines are divided further into two additional types; namely upwind and downwind. Turbines can be upwind or downwind depending on the position of the blades to the tower structure that they’re connected to. Thanks to tower turbulence, downwind turbines are often less efficient than upwind turbines.
Upwind turbines must be designed in a way that allows them to face the wind in order to improve efficiency. A wind vane is what’s typically used to keep smaller turbines in place to face the wind while larger turbines have a motor and some sensors to achieve the same thing.
- Vertical Axis Wind Turbines
Vertical axis wind turbines are considered to be the most efficient because they work regardless of the wind’s direction. Vertical axis turbines come in different types too. There are eggbeater turbines or Darrieus which have airplane wing-like blades that move in a horizontal direction. Meanwhile, Savonius turbines have cup-shaped blades that they use to effectively “catch” the wind. Each of these models has its own set of issues to be aware of, mostly pertaining to efficiency.
The invention of the world’s first electric generator came in the year 1831 courtesy of Michael Faraday. For the first time, humans discovered that it was possible to create an electrical current through the use of a rotating magnetic field. Obviously, technologists have made significant improvements to this design since then, with a few variations having been developed for wind turbines.
DC generators are great for smaller wind turbines specifically, as larger models are typically connected to a central power grid and use AC energy. Small sized turbines are able to direct energy straight to the generator because they spin at extremely fast speeds. However, larger turbines rely on transmission or a gearbox in order to create enough speed and power.
What’s the best way for a wind turbine to work efficiently without encountering turbulence?
First of all, you have to look into the design of the tower. There’s likely to be additional turbulence near the ground than higher up. This is produced by the surface of the Earth which is known as the boundary layer, and the tower is designed to keep the turbine above this line.
On the flip side, the rotor needs to be placed in a high position in order to achieve maximum efficiency. Meanwhile, the tower will experience additional pressure because the wind is doing a push and pull motion in which it’s pushing the tower while turning the rotor. A taller tower acts as a long lever that’s supported by the base of the tower since the rotor is attached to an aerodynamically designed nacelle that helps to minimize drag.
Large towers are usually designed to have a cylindrical cross-section in order to avoid the drag caused by latticework towers. As a result, cylindrical towers experience a reduced amount of drag when compared to latticework towers.
Needless to say, there’s plenty of room for improvement when it comes to the design of wind turbine towers, and current research is mostly focused on improving strength and design while lowering construction costs.
Wind turbines are complex pieces of machinery that are made of many different parts. While this guide has been rather short and concise, we hope that it has covered the most essential aspects of wind turbine design and performance.
Hopefully, you can now answer questions like how fast do wind turbines spin or what is the best shape for a wind turbine blade. This information will help you to better explain how wind turbines work to someone who’s a skeptic of sustainable energy.
It’s important now more than ever for the human race to shift to more sustainable forms of energy like wind power in order to ensure the survival of our planet. Fossil fuels are an obsolete form of energy that’s no longer sustainable for the longevity of the Earth and its inhabitants. So it’s crucial that we continuously raise awareness about the benefits offered by wind turbines, and the only way to do that effectively is to be knowledgeable ourselves.