How Wind Power Works





A wind powered device can really be anything that uses wind energy to perform mechanical work. This article on how wind power works focuses on the generation of electricity from wind energy since this also encompasses the basics of all wind power.

Source of Wind Energy

In a way it can be misleading to think of wind as the source of energy for wind power because the wind is caused by the sun. Wind power is simply harnessing solar energy through an alternate channel. The sun heats the surface of Earth unevenly resulting in pressure differences caused by the difference in temperature. As these pressure differences attempt to equalize they cause what we refer to as wind. There would still be wind without the Sun since the surface will always have temperature differences but the Sun is the primary contributor to global capacity for wind power.

Diagram of how wind energy is created. Image by US DOE.

Diagram of how wind energy is created. Image by US DOE.

Conversion of Wind to Electricity

The basic concept of wind power starts with mechanical motion provided by rotors turned by the wind. This rotating motion can be used to generate electricity with an electric generator. According to Faraday’s law of induction a changing magnetic field relative to a circuit creates electromotive force.[1] If the circuit has an electrical load then current is generated and electricity is produced. The simplest model of an electrical generator is a permanent magnet passing through coils of copper wire, attached to a battery or other load, to generate electricity. Fossil fuel, propane, human, natural gas, and wind generators all rely on Faraday’s law of induction to generate electricity from motion.

Wind Turbine Design

Modern wind turbine design incorporates several advanced features to improve efficiency and safety. Rotors are designed to maximize low power torque while also maintaining long service lives upwards of 20 years in some cases. Wind speed and direction is monitored by individual turbines and used to adjust pitch and yaw. Pitch adjustments turn the rotors to prevent damage in high winds and yaw adjustments keep turbines facing into the wind. Control units even apply brakes to shut down wind turbines when wind is either too high or low. Rotor designs are made with sophisticated modeling tools that analyze rotor profiles to maximize performance and structural integrity.[2]

Illustration of wind turbine parts. Image by US DOE.

Illustration of wind turbine parts. Image by US DOE.

Wind Turbine Operation

Once a wind turbine has been built and is operational there are still things that must be done. Regular checkups are required to keep everything running smoothly. The gearbox, blades (rotors), brakes, electric generator, batteries, and all the components that connect these systems require regular maintenance and repair.[3] Things like bearings, lubrication, oil, hydraulic fluid, and brake pads are all routinely inspected and replaced as needed. Many wind turbine owners also choose to upgrade as more money or new technology becomes available. These upgrades could be in the form of more efficient rotors or hybrid bearings [4] for example.

Personal Wind Power vs Industrial Wind Farms

When thinking about wind power it’s important to remember how different the concerns, costs, and benefits are between personal wind power and industrial wind power (wind farms). Many people use small scale wind turbines in their backyard to offset some of their electricity uses. The effort and issues that face this kind of use are quite different than those of a large wind farm spanning hundreds of square miles and generating hundreds of megawatts of electricity.

Wind Turbine Construction Video

Below is a video of a wind turbine being constructed from start to finish.

Sources:

1. Faraday’s Law
2. Boise State; Wind Turbine Rotor Design
3. Wind Turbine Inspection Services
4. Wind Turbine Servicing

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