Mankind has been harnessing the power of the wind for thousands of years. First we used it to help thresh grain carrying away the chaff that was separated. We then discovered how to harness the wind’s energy to propel our ships. Finally we used it to grind wheat and pump water with wind mills. In the 20th century with the discovery of how to harness electricity the first wind turbines were built. Now as the world tries to wean itself from fossil fuels as an energy source wind turbines are one the tools we are relying on to provide clean and unlimited energy. So how does a wind turbine work?
The process starts with elementary physics. We know that energy is neither created or destroyed it is only transferred or changes form. We also know from Newton’s Third Law of Motion that for every action that there is an equal and opposite reaction. All these principles are at work with a a wind turbine.
The rising of hot and air and and sinking of cooler air due to temperature changes is what create movements in the atmosphere, called wind. A wind turbine simply take some of the kinetic energy of wind as it hit its propellers and converts it into electricity. But how does this process occur.
A wind turbine is quite simple in design. There are the propellers just mentioned, a shaft and a generator. The propellers catch the wind and help rotate the shaft. The turning of the shaft helps to power the generator and create electricity. A generator will normally consists of magnets and a conductor such as coiled copper wire. The array of magnets are connected to the shaft and surround the coil of wire. When the magnets rotate around the copper wire its produces a different in electrical potential creating voltage and an electric current. This process is called induction and it is how generators of all types produce electricity.
Currently there are two types of wind turbines. There are the Horizontal Axis Wind Turbines and Vertical Axis Wind Turbines. The horizontal axis wind turbine works just as the name implies. The shaft is horizontal and perpendicular to the propellers. The vertical axis wind turbine works differently and the shaft and rotors are vertical and parallel to each other.
In general the Horizontal axis wind turbine is considered more efficient and can produce more power. The vertical model needs a certain amount of electricity to get its rotors turning and is on a lower elevation so it is not as efficient or powerful. There are some concerns about wind turbines being dangerous for local birds but the consensus is that it is one of the most environmentally friendly ways to produce energy.
If you enjoyed this article there are other articles on Universe Today that you will enjoy. There is an interesting article about wind power on the ocean. There is also an interesting article about a company seeking to provide space based solar power.
There are also great resources on the internet. The Discovery How Stuff works website has some great information about the history and mechanics of wind power. There is also a news article on Huffingtonpost.com about a wind powered land vehicle and the future of transportation.
You can also listen to Astronomy Cast. Episode 144 Space Elevators is interesting especially about the implication for renewable energy.