A home windmill or residential wind turbine operates the same way as any other type of turbine-based electricity generator. Regardless of the type of “fuel” used to power the turbine, the principles are the same.
In the early 1800s a British scientist, Michael Faraday, discovered the principle of magnetic induction. In simple terms, what he discovered was that if you moved a magnet near an electrical conductor then electricity was generated. Similarly if you move an electrical conductor near a magnet then electricity is generated.
On top of this, the opposite is true. By introducing electrical energy into a wire near a magnet, the magnet can be made to move.
This discovery lead to what we now know as electric motors and generators. Motors and generators are two sides of the same coin. Motors take electrical energy and convert it into mechanical energy (movement). Generators take mechanical energy (movement) and turn it into electrical energy.
After much experimentation it was discovered that one of the most efficient ways to generate electricity using this principle was to have a coil of wire rotating within a magnetic field. This is the principle behind most turbines, whether it be a nuclear power station, or a home windmill in your back yard!
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There are numerous ways to create the necessary rotation, of which steam is one of the most common. When water is heated it will eventually turn to steam. And the expansion of steam creates a lot of pressure and can be used to move even very large objects. Ever seen a steam train?.
There are many ways to create steam for use in power generation, including the burning of coal or other fossil fuels, or through nuclear reactions. The energy created from burning fossil fuels or from nuclear reactions is used to heat water to turn it into steam. An alternative source of steam is that from geothermal vents, where the steam is created deep inside the earth.
Hydro-electric power on the other hand uses the motion of water to power the turbines, while windmills obviously use the power of the wind.
All of these methods involve moving a fluid past an object, causing it to rotate, and hence creating the ability to rotate a wire coil through a magnetic field, and hence producing electricity.
Because this is such a simple mechanism, it can be scaled to all sorts of different sizes, from power plants generating enough electricity to light up a city, to wind-up flashlights or radios. (think war movies and their field radios, powered by winding a crank).
And of course the same mechanism is used in windmills, from the biggest windfarms to the most basic home windmills anybody can erect in their own back yard. Wind turbines are nothing more than a basic generator, taking the mechanical energy of the wind and converting it into electricity.
