Wind turbines come in a vast range of a sizes. From those powering garden lights, so the MHI-Vestas 8MW with its 80-metre blades. If you want an idea of the scale and size of the largest, the view the 'World's biggest wind turbines'.
On a very basic level, the heart of a wind turbine is its generator. A wind turbine generator works on the same principle as any other generator for electricity such as hydro, nuclear, thermal.
In short generators transfer kinetic energy into electricity. It uses the principle of electromagnetic induction discovered by Michael Faraday in 1831-32.
Faraday realised a flow of electric charges could be created by moving an electrical conductor in a magnetic field. An example of a conductor would be a copper wire, which contains electric charges.
This movement creates a voltage difference between the two ends of the wire or electrical conductor. This difference causes the electric charges to flow and generate an electric current.
For more on the different components of a generator, go to the energy glossary.
A wind turbine works in the opposite way to a fan. The wind it hits the blades which then operates the generator inside the nacelle.
Wind turbines use a geared or direct drive system to regulate the amount of turns made by the generator. Additionally, a pitch control system keeps the blades facing the wind.