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How is Wind Energy Produced

How is Wind Energy Produced? Let's Get Back to Basics

The answer to how wind energy is produced can help you get rid of all the myths surrounding the concept of power generation by harnessing the kinetic energy of wind. Read on...
Abhijit Naik
Last Updated: Dec 10, 2017
Large white windmills in the sea with a sailboat
Our desperation to find an alternative energy source continues to intensify, as we inch towards the exhaustion of fossil fuels. In the race for the best, one of the most likely contender happens to be wind energy - wherein the kinetic energy of wind is converted to mechanical energy and used to power the generator, which in turn, produces electricity. However, the same has also been under the scanner for quite a few reasons of late - efficiency (in terms of returns) and environmental threat (for birds in particular) being the most prominent among them.
Wind Energy Production and Development
The entire concept of 'wind energy' refers to the process of harnessing kinetic energy of wind, and using the same to generate electricity. However, this is just an overview of how wind energy is produced, while the actual process involves various steps - right from generation of wind on the planet to power generation in from alternating current.
Wind Generation on the Planet
The heating of the Earth's surface as a result of solar radiation differs in accordance to region, landforms etc. Not all the regions on the planet are subjected to same amount of sunlight, and hence, the speed at which these regions heat differs from one region to another. Similarly, the heating of air on land is faster as compared to heating of air over the ocean during the day time, and the same is reversed at night. When air is heated it starts rising, and the vacuum created by this rising hot air is filled by cold air from the surrounding taking its place. This movement of air as a result of heating results in formation of wind - which is nothing but movement of air.
The speed at which the wind blows depends on several factors, and obstruction in form of natural or man-made structures in one of them. That explains why wind speed is high over the oceans wherein there are no obstructions as compared to land wherein friction with structures reduces its speed. Wind speed is classified into seven major classes - numbered 1 to 7, with 1 being the lowest speed and 7 being the highest. It is this movement of wind which is the basis of its kinetic energy, and the device which converts this kinetic energy of the wind to mechanical energy is referred to as a wind turbine.
More on Wind Turbines
Wind turbines come in all shapes and sizes. When it comes to shape, they are classified into two major types - vertical-axis wind turbines (VAWT) - resembling an eggbeater, wherein the main rotor shaft is located at the center and horizontal-axis wind turbines (HAWT) - resembling a fan with 3-4 blades, wherein the main rotor and generator are located at the top of the tower. Unlike HAWT, it is not mandatory for the VAWT face the wind. On the other hand, the size depends on what the mechanical energy derived from the wind turbine will be used for. The ones used for individual home use by people who live off the grid are generally small, while the ones used for commercial electric power generation are large.
Electricity Generation
When these turbines are subjected to wind, the rotor in them begins to spin. While the wind is already laden with kinetic energy, it comes in contact with the blades of the turbine and rotates them. The rotation of blades in turn spins the rotor, and produces mechanical energy. A similar principle was earlier used to power windmills for grinding corn, pumping water, etc., wherein the force of wind was used to rotate the blades of the windmill which in turn powered a wheel inside the structure. The same principle can be seen in modern wind turbines, however, in these turbines the rotation of blades eventually powers a generator - instead of some wheel, and the generator produces electricity in form of alternating current.
Wind Energy Pros and Cons
Even though everything seems to be pretty calm, the picture changes when you pitch the pros and cons of wind energy against each other. The positive attributes of wind power generation include the fact that it is a renewable and environment friendly source of energy, while the negative attributes of the same include high initial infrastructure cost, low returns, etc. In fact, critics of wind energy also argue that environment friendliness that this alternative energy source boasts of, doesn't quite hold ground if you take into consideration the amount of noise pollution these structures cause or the threat they pose to the wildlife.
As far as wind energy efficiency is concerned, the theoretical maximum output of the same happens to be a mere 30 percent. Even though these wind turbines cannot convert the entire kinetic energy of wind into electricity - as there would be no air left on the other side of the turbine, something around 50-60 percent shouldn't be too much to ask for.
Does that mean we are wasting our time trying to assess the feasibility of this source of power? Absolutely not! There is no doubt about the fact that wind energy does stand a chance to become the power source of the future, especially with all the other alternative energy sources having their own pros and cons, but for that to happen we need to work on it and increase its efficiency and minimize its drawbacks to make sure that it overshadows its contenders.