Wind+Energy

=Wind Energy=

How it Works
Wind is generated when the Sun heats the Earth's surface unevenly creating convection currents. As air heats up, it becomes less dense and rises above cool air which replaces it. As the hot air rises, it cools, becoming more dense, and falls. This creates currents of moving air or wind.

Wind turbines are designed to harness the kinetic energy in wind. When fast moving air causes the two or three blades to rotate, spinning a low speed shaft which in turn, rotates a high speed shaft. The high speed shaft is positioned within a generator that converts kinetic energy to usable electrical energy.

A Brief History
Wind has been used as a source of power since as early as 200 B.C.E in China to pump water and grind grain. The earliest windmills were the vertical axis type where the blades run parallel to the shaft, often in a conical formation. In the 13th century in Holland, horizontal axis windmills (closely resembling the ones seen today) were d eveloped. These windmills were more efficient as they are able to work with more torque and higher wind speed. The use of wind power became popular in North America in the 1970s during the Arab Oil Crisis when forms of renewable energy were explored. Projects persuing the use of wind energy as a renewable research lost funding during the 1980s and early 90s due to a stabilization in oil prices but they were resumed in the mid 90s when the interest in "green power" intensified.

The Physics Behind Wind Turbines
First, the rotor’s energy from the wind must be harnessed and converted into a speed at which the generator can use it, since many generators operate at much higher speeds than the rotors turn. Gears are used in this conversion, as the use of gears with a different number of teeth and sizes allows the rotating speed to change, along with torque, while the total amount of power remains the same. Generators can be either synchronous or [|asynchronous (definition)], but asynchronous generators are more common since they use induction and produce AC current. Induction is the process by which a magnetic field is generated by creating a current flow throughout a wire. This process can be used to create energy through the generators. First, the armature (electromagnet) is forced through the magnetic field, which creates a current. Lenz’s law states that “the direction of the induced current creates an induced magnetic field that opposes the motion of the inducing magnetic field”. Therefore the current through the electromagnet will flow in one direction for a half-turn but will switch directions for the next half-turn. If this process continues, an alternating current will be produced.

** Advantages **
Wind is an extremely beneficial energy source. Firstly, wind is an entirely free and unlimited resource. By utilising wind energy, we are able to conserve other resources such as water and fossil fuels. Unlike fossil fuels, wind energy does not emit any waste products or release any harmful toxins. The lack of toxic emissions allows us to lower our impact on climate change. Wind energy is being established as one of the most economical energy sources for large-scale electricity generation. In the past twenty years, the cost of wind-produced energy has been reduced by more than 80%.

Aside from the obvious benefits, the usage of wind energy also has some unexpected benefits. By erecting wind turbines, economic development (especially in rural areas) is encouraged, and land use is diversified. Using wind energy is very helpful in reducing energy costs in remote locations that already have high energy prices such as rural communities and in Northern Canada.

** Disadvantages **
Like any other form of energy generation, however, there are some disadvantages to the use of wind energy. The greatest disadvantage would be the unpredictability of wind. Because wind is unpredictable and it is unreasonable to assume that there will always be enough wind to generate the required amount of electricity, there must be an alternative plan. An option that is often used is the storage of energy generated during windy times to be used during calm times. Another possibility is the coupling of wind energy with another, constant energy source so in calm times, people may still use electricity. Wind turbines also have one other disadvantage: their citing is key. The type of turbine must match its environment; turbines cannot simply be placed anywhere and still harness the energy of the wind. Also, the blades of the turbines create noise and altogether, they are unaesthetically pleasing.

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