Wind Power: Are You a Big Fan?

Although most of you have heard about wind power, I bet not all of you knew that wind power is technically a form of solar energy! Wind is caused by an uneven heating of the atmosphere by the sun along with irregularities of the earth's surface, and the rotation of the earth. Through the use of wind turbines, this wind energy is "harvested' and used to generate electricity.

Courtesy of Inhabitat

Wind turbines can be thought of as a reverse fan. Instead of using up electricity to make wind, turbines harness the motion energy of the wind and transforms it into electricity. When wind turns the blades of the turbine, the blades spin a shaft, which is connected to a generator that makes electricity. 

Today, there are two types of wind turbines that are used. Horizontal-axis turbines include a blade or rotor, which converts the motion energy of the wind to rotational shaft energy; a drive train that includes a gearbox, which amplifies energy output of the rotor, and generator; a tower that supports the rotor and drive train; and other miscellaneous equipment (e.g. controls, electrical cables, and ground support equipment) (Turbines Info). 

Vertical axis wind turbines are the second type. Vertical axis wind turbines are less efficient than horizontal axis ones, which is why most people have only seen horizontal-axis turbines (pictured above). The most commonly used vertical axis wind turbine is the Darrieus model. In this turbine, two vertically oriented blades revolve around a vertical shaft. Using the same process of airplane wings during lift off, the turbine's blades take advantage of a "lift" force that is created when air is passed through the blades. Instead of flying away though, the blades are attached to a generator shaft, and the air passed by is converted into rotational momentum which turns the generator (Mother Earth News). 

Courtesy of InDepthInfo

Wind energy has been used as early as 5000 BCE to propel boats along the Nile River. Later on in 200 BCE, windmills were being used in China to pump water, and vertical-axis windmills were grinding grain in Persia and the Middle East. 

Courtesy of not-about-books

In America, colonists used windmills to grind wheat and corn, pump water, and cut wood at sawmills. However, after electricity was developed, wind plants that could be connected to electricity grids were invented, creating a new use for wind power. 

During the oil shortages of the 1970's, the use of wind turbines to create electricity seemed to be a very viable option. The government took advantage of this and from 1974-1980 they worked closely with the industry to develop large commercial wind turbines. After this program, 13 experimental turbines were put into operation, and many of the multi-megawatt turbines used today came from these first 13 turbines. 

However, when the oil shortage was over and prices decreased during the 1980s and early 1990s, wind power became viewed as uneconomical. Despite this, wind energy flourished in California due to federal and state tax incentives which were implemented to encourage the use of renewable energy sources. Sadly, the use the wind energy slowed dramatically after these incentives were removed (energy.gov). 

Wind energy, has many advantages that are similar to other renewable energy sources. Wind energy is a clean source since it doesn't require the use of any destructive chemicals. Also, relying on wind energy lessens our needs for fossil fuels from outside nations, helping our national economy. Furthermore, wind energy has seen enormous growth in the last decade, with an increase in wind power capacity of an average of 30% per year. Wind energy accounts for about 2.5% of the total worldwide electricity production. Lastly, wind turbines can be built on existing farms where farmers can reap benefits but not lose a lot of their land. 

Wind energy also creates many disadvantages. First, wind doesn't generally blow reliably, making it difficult to have a consistent source of energy when the weather isn't cooperating. Second, the sharp blades of wind turbines can be a threat to wildlife, specifically birds and other flying creatures. Third, wind turbines make a sound that is between 50 and 60 decibels which although not extremely loud, can become a nuisance. Finally, wind energy can only be harnessed in certain locations where the wind speed is high enough. Most of these areas are in remote areas, which means new infrastructure needs to be built and maintained in order to bring power to residential homes in the city. 

As this blog comes to a close, I hope my posts have opened your eyes to the myriad of renewable energy sources available. Maybe in the future you'll take advantage of some of them to power your house, or vote on legislation regarding the use of these renewable energy sources.