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How does a wind turbine generate electricity from wind?
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energy conversion
Before the Industrial Revolution, power came from three main sources: humans, draft animals, and water.
The ingenuity people used in harnessing waterpower can be seen in this medieval-style mill. The waterwheel is turned by a stream and is connected to a shaft that leads into the building. At the other end of the shaft is a gear. The connection of a series of gears translates the power from the stream to a shaft that drives a millstone, which grinds flour from grain.
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A wind turbine generates electricity by converting the kinetic energy of moving air into mechanical energy, which is then used to produce electricity.
The process relies on the interaction between the wind and the turbine's blades:
- Energy Extraction: As wind flows over the turbine blades, it exerts a tangential force, or torque, on the rotor. This causes the rotor to turn, effectively extracting work from the fluid stream.1
- Blade Design: The blades are aerodynamically shaped to capture the wind efficiently. In common horizontal-axis wind turbines, the blades resemble aircraft propellers. These blades must be strong enough to withstand mechanical stresses while being positioned to optimize the conversion of wind velocity into rotational energy.23
- Efficiency Limits: According to Betz’s law, a turbine cannot capture more than 59 percent of the wind's kinetic energy. The actual power generated depends on variables such as blade shape, the rotor's swept area, and the speed of rotation.2
Once the rotor is spinning, this mechanical energy is typically converted into electrical power for use in homes or power grids.12