After my post a few weeks ago about vertical axis wind turbines, I received several emails asking me for more information about how wind turbines work and how they generate electricity. And thus, this post was born! The majestic beauty and silence of a tall wind turbine working hard to provide clean, efficient energy is awe-inspiring. Since large wind turbines are showing up in open fields and small ones on rooftops, let’s take a look at what a wind turbine is, how they work, and who makes them.
Modern wind turbines are actually a pretty simple concept based on age-old science. The inherent kinetic energy in moving wind spins two, three, or even four propellor blades which are connected to a rotor hub. This rotor spins a central shaft through a gear box, which dramatically increases the rotational speed of the shaft. (Think of your bicycle gears and how they help you get up steep hills.) The shaft then in-turn spins a generator which makes electricity.
The generator makes the electricity through electromagnetic induction, the result of a conductor (coiled wire) moving through a magnetic field (magnets). This electricity can then be stored in batteries for later use or sent out to the power grid. In order for a wind turbine to be effective and efficient, they should be mounted as high as possible and capture wind speeds above 10 miles per hour. That’s why they are so tall out on those wide-open fields of the midwest!
While wind turbines are simple in concept, it takes more than just a fan blade and a steel pipe to build one. Starting at the top, the propellors are usually made from either simple plastics (for home or small-scale wind turbines) or fiberglass and carbon-fiber-reinforced plastics (for full-size turbines). The bases for the super-tall wind turbines are made from steel-reinforced concrete to withstand the amount of energy those moving blades generate in high winds. The various generators, motors, and electricity converting/delivering systems are built inside the sheath behind the propellers and the base attaching the wind turbine to the ground.
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