Group 4 - Article

WIND: A Power Supplement


The objective of this article is to educate the reader on the history of wind power, the current utilization of wind power, and the future outlook of wind power. There are several benefits to the use of wind power including its lack of emissions, economic competitiveness with conventional technologies, and its small impact on the environment. There are also several drawbacks such as the intermittent nature of wind power, the threat of turbines to wildlife, and the threat that turbines pose to workers. Overall, wind power is a viable source of renewable energy that cannot be relied upon as the sole source of electricity for a county, but can be used to supplement other sources.


It is uncertain when exactly windmills were introduced. However, it is known they were used primarily to pump water and grind grain on farms by having the wind turn an assembly of blades, which was then connected to a gear or system of gears and could turn them. The first windmills were very crude and inefficient, but they did show some understanding of aerodynamics, since wind power was what propelled the sailboats made during that time. The design of windmills improved over time, and windmills became more efficient machines before physics and aerodynamics were fully understood (Carlin 1). However, windmills always had one big weakness: although easy to obtain, wind was an unreliable energy source on land.

Persia was one of the first places to use windmills. According to Bent Sorenson, they started using windmills about 800 AD (7). Their windmills used a vertical axis design in which the blades were attached to a vertical mount instead of the horizontal mount seen today. The windmills had a shield on the side advancing toward the wind to increase rotor efficiency. The blades were sailcloth, and the remainder of the windmill itself was made of reeds and wood. Sadly, this was an inefficient design because it could only capture about half of the power of the wind. Yet, it was a popular design until about 1200 AD. It was revived from time to time afterward, but never successfully.

Around 1200 AD, the Europeans started making a different design of windmills. This design was largely based on existing water wheels (Dodge) and thus was easier for them to make. These new windmills used a horizontal axis design in which the blades were attached to a horizontal mount. These windmills looked like modern-day ceiling fans or table fans. They were variable speed and could be controlled only by braking or furling, but a particular speed was not important then (Sorenson). This new design required less shielding, could capture more power from the wind, and was here to stay. Also, it would be perfected in the next six hundred years to become a common design of windmills today. By 1800 AD, the following improvements had been made to windmills: a camber along the leading edge, placement of the blade spar and center of gravity at the quarter chord position, and a nonlinear twist of the blade from root to tip (Dodge). Windmills became one of the earliest forms of the electric motor and could be very large and powerful. However, the invention of steam engines sent the use of windmills into decline in 19th-century Europe—steam was a more reliable source of energy than wind.

Windmills got a revival in the 19th century United States of America and the world thanks to the invention of steel blades in 1870 (Dodge). Steel was durable, lightweight, and easy to make into aerodynamically efficient shapes for windmill blades. It was a great improvement over previous wood blades. Also, steel allowed for windmills to be smaller and yet more powerful than older designs. Eventually, the whole windmill itself could be made of steel, which allowed the windmill to be grounded. Grounding the windmill increased the resistance to destruction by lightning strikes. This steel design became popular quickly and eventually became the first windmills used for generating electricity at the end of the 19th-century.

This revival did not last long. The unreliability of wind energy proved to be problematic as more and more electrical appliances were invented. By 1940, the average household had too many appliances for wind to be a sufficient power source. Part of this problem was the design of the windmills themselves: the fan-like design had become insufficient, and better designs were needed for capturing wind. Another problem was these new appliances required alternating current, which early wind generators could not provide. So, small wind generators in the United States became extinct by 1950. (Dodge) However, these problems did not affect wind energy in the rest of the world.

By the 1970s, sufficient improvements had been made to make wind energy a viable power source. The blades of windmills were reshaped to look like airplane propellers, which helped to capture more wind. The new blades were also made of fiberglass, which made the blades even more lightweight. Alternating current generators for windmills had been developed. Between 1973 and 1986, a change was made from installing individual windmills to wind farms (Dodge), which can generate a lot of power because of the combination of windmills and generators. Often these are placed where they can be out of sight and where there is normally a lot of wind; mountainous areas and deserts are usual candidates for windmills. Also, since methods for construction at ocean are understood now and running electrical wire under the ocean is possible, some wind farms are being constructed off the coast where the wind is more reliable and the windmills are out of sight, such as off Cape Cod (Kemp 125).

How Wind Power Works

The first windmills for generating electricity as well as modern windmills were built largely the same way as for farming windmills, but these were connected to a generator. This idea made windmills into a motor. They worked as follows: Wind would turn the blade assembly, which would then turn a turbine or perhaps a system of gears and then a turbine, and then turning the turbine would cause the generator to produce electricity.

Even though wind farms are the most common way to install windmills, some are still installed at private residences. Sometimes, these windmills are attached to the power grid, and they often generate excess power that can be sold back to the power company; thus, the homeowner often does not have to pay electric bills.

Benefits of Wind Power

Economic Considerations
The cost of wind power has decreased to an economically competitive price of $55.8 per megawatt-hour generated. 73% of the cost of the wind power is associated with the initial capital outlays when constructing a wind farm.(U.S. EIA 2006) Wind energy is a renewable resource, which has zero fuel costs. Therefore, while the upfront costs of a wind farm are greater than other conventional technologies the marginal cost of producing energy is close to zero. (World of Wind Energy 2011)


Source: <>
Figure 1: The table below details the cost of wind power versus alternative fuel sources in 2006. The values represent the cost of the technology in dollars per megawatt hour.

The renewability of wind power is the driving force behind the competitive of wind energy. In fact, in a survey conducted by Federal Energy Regulatory Committee of 128 wind farm projects between the years 1998 to 2007, wind power was price consistently at or below the national wholesale power price average. (Wiser 2007)


Source: < >
Figure 2: National Wholesale Power Price Average vs. Average Wind Power Price

Increases in the price of fossil fuels would drive investment into alternative energy sources such as wind power because the cost to fuel such sources is free and therefore the price of production is predictable.

Residential wind power sources of electricity are also available to consumers. These electricity solutions provide between 5 and 15 kW/hr for the home and cost between $5,000 and $22,000. These solutions may decrease the cost of a home’s monthly electric bill by 50 to 90 percent. (Knol 2011)

Environmental Benefits
The use of wind turbines in the production of energy does not require the use of fuel. Therefore, the production of electricity causes zero direct emissions of air pollutants. Conversely, the use of fossil fuels such as oil, coal, and natural gas to produce electricity contributes to the production of air pollutants and greenhouse gasses. The generation of electricity through the use of fossil fuels is the leading cause of air emissions on the planet, which can contribute to climate change. Fossil fuels are responsible for 39% of carbon dioxide emissions, 22% of nitrogen oxide emissions, 69% of sulfur dioxide emissions, and 40% of mercury emissions. (Jacobson 2011) Thus, the utilization of wind turbines not only decreases the output of emissions directly, but also indirectly through the displacement of fossil fuel power plants. As companies choose wind power over conventional alternatives, the number of conventional, emission producing power plants will diminish relative to power needs, consequently decreasing the amount of total emissions produced in electricity production. The MGE wind farm in Madison, Wisconsin alone saves 13,100 tons of coal prevents the production of 18,880 tons of carbon dioxide.(MGE 2011) It would take a forest 3,776 acre forest to absorb the equivalent amount of carbon dioxide. (MGE 2011)

The leading emissions created by fossil fuels also have severe health and environmental impacts on the surrounding area. Carbon dioxide is the main contributor to global warming. Sulfur dioxide causes regional haze, is a major contributor to acid rain, and is associated with diseases of the heart and lung. Nitrogen oxide is a precursor to ozone ground level ozone, which can exacerbate lung conditions, and can contribute to the formation of particulate matter, an airborne carrier of toxin substances. Utilizing wind power can reduce the production of such materials.

Wind power does not use our precious fresh water sources in the production of energy. Irrigation and thermal energy production account for 77% of the use of fresh water in the United States.(Department of Energy) Electrical energy is produced entirely by the action of wind on the turbines, therefore unlike thermal power, nuclear power, and conventional power plants, wind turbines do not use water.

The construction of wind farms also has very little impact on the environment. As many as twenty turbines , spread over an area of one square kilometer, would use less than 1% of the land that was available. (BWEA 2011) Larger turbines may require more land, with the largest sites using up to 5% of the land area. Of the 603 acres of land on which the MGE wind farm is built in Wisconsin, 30 acres are reserved for the wind farm and only 7.4 acres are unavailable for farming or grazing.(MGE 2011) This land dedicated to the wind farm would be used for power lines, roads and the turbines themselves. The remaining 95-99% of the land could still, and often is, be utilized for farming. Each year a farmer can generally expect between $2000-$5000 in compensation per turbine. (GAO 2011)

Disadvantages of Wind Power

Intermittent Power
The production of power through the use of wind turbines is dependent on a consistent supply of wind. However, various weather patterns can cause a disruption in this supply, therefore causing a disruption in the generation of electricity from the turbines. The National Weather Service estimates that due to these intermittent disruptions in the stream of wind supplying the turbines we can only rely upon the wind farms to produce between 33% and 47% of their total yearly power at any given time. (Science News 2011) Proponents of wind power argue that if there are enough wind farms connected to a grid over a large enough area, the intermittency of wind power is not a concern, however sufficient back up power supplies should be utilized. (Disendorf 2007)

Furthermore, there are limitations as to the maximum efficiency of wind turbines. Because the wind that enters a wind turbine must leave through the back, 100% efficiency of turbines is impossible. Wind turbines are limited to an efficiency of energy transfer of 59%, also known as Betz’s Limit. (Grogg 2005)

Possible Dangers
Windmills also have negative impacts on the environment. For example, windmills are associated with an increase in bird deaths. Birds fly into the windmills and are killed. According to Drewitt, the problem is that the windmills are frequently located in areas inhabited by scarce and vulnerable birds (238). However, the impacts of windmills do not stop with bird deaths. According to Drewitt, wind farms act as an ecological sink (238). The ecosystem is changed as other birds move into the area. Environmental groups often present stiff opposition to windmills because of the possibility of ecosystem change.

Seabirds and migrating passerines are always at risk of collision at the offshore sites. Another example is the death of golden eagles at the Altamont Pass wind farm in California. Because the site had 7000 turbines the mortality was sizable. Despite that, the rate of mortality in general is relatively low, from 0.01 to 23 mortalities per turbine per year. This is true for both of the on and offshore wind farms.

The way mortality was measured at the onshore sites was different than the one used at the offshore environment. At the onshore sites, mortality was generally measured by counting dead birds found near turbines and correcting for birds removed by scavengers. On the other hand, counting carcasses was found to be very difficult in the offshore environment. That was many carcasses will not be found.

In an attempt to overcome these issues, wind industries and government agencies have conducted researches on collisions, relevant bird and bat behavior, mitigation measures, and design protocols. Moreover, data collection at existing and proposed wind energy sites is required in order to minimize fatalities. In addition, additional research may be needed to address bird and bat impact issues in some cases.

While structures like smokestacks, lighthouses, tall buildings, and radio and television towers have also been associated with bird and bat kills, bird and bat mortality is a serious concern for the wind industry. Several wildlife agencies and conservation groups are also concerned.

Turbine's spinning blades can be sometimes a risk to birds; however, wind turbines are actually less deadly than office buildings and domestic cats. Indeed feline pets kill so many more birds than wind turbines.

Windmills have other disadvantages that often lead to community opposition. Windmills are noisy and generate a lot of turbulence. Windmills cause enough turbulence to force birds to the ground (qtd. in Drewitt 238). Many people are opposed to the noise and the appearance of windmills, which is why they are often located in remote areas. Some of these remote areas have been mountain ridges, where environmental groups and some residents have opposed the installation of windmills.

Windmills also have safety problems to address. Besides bird mortalities, there have been human mortalities due to windmills spinning out of control. According to D.M. Dodge, Terry Mehrkam, who invented the Mehrkam design of windmills, died while trying to stop a rotor overspeed on one of his designs. Indeed, since most windmills are variable-speed and hard to stop, maintenance is hard to do on windmills until the wind stops. Some windmills have braking systems installed on them, but even these systems cannot slow down a windmill from a high speed without being destroyed themselves or destroying the windmill.

Because wind turbines produce some noise during its operation there were several law suits and complaints in several states regarding turbine noise. Families and homeowners claimed that it affected their property values. For instance, residents who live near the wind facility in Vinalhaven, Me., claim that the nose produced by the blades is making their life unbearable.

The noises generated by wind turbine operation can be divided into two types:

1) Mechanical, caused by the interaction of turbine components and the dynamic response among them. This includes the gearbox, generator, yaw drives, cooling fans, and the auxiliary equipment.
2) Aerodynamic, originated by the flow of air of the blades. This kind of noise increases with rotor speed.

There are no hard proofs that back most of these claims. In a paper published by the American Wind Energy Association (AWEA), it was concluded that there is no evidence that the sounds emitted by wind turbines have any direct physiological impacts. Also the Energy Department conducted a separate study proving that property values were not affected by the nearby wind farms.

Most of the turbine noise is masked by the sound of the wind itself, and the turbines run only when the wind blows. In addition, wind turbines designs have been improved in order to reduce its noise. Most of the new models are less noisy than the older ones. Engineers now try in their new designs to convert most of the wind into rotational torque and less into acoustic noise. The use of proper siting and insulating materials helps to minimize noise impacts.

Bad View

Wind turbines are often highly visible because of its exposed locations. However, being visible is not the same as being intrusive. Aesthetic issue can be subjective sometime. Proper siting decisions eliminate any aesthetic effects to the landscape. One strategy being used to partially offset visual impacts is to site fewer turbines in any one location by using more than one and by using larger and more efficient models of wind turbines.

Future of Wind Power

Despite the various setbacks as discussed in the previous section, integration of wind power into national power grids has seen a steady increase. As it stands today, many nations are making an effort to increase their wind power generation capacities, while others already harness the power of wind as a major source of their power national power supply. For example, in the year 2010, Denmark produced 3,752 MW of electricity from wind power, contributing to 21.9% of their total electricity supply (Unlisted 2010). Unfortunately, this is the highest percentage electricity share found anywhere else in the world. From a raw, power-generated perspective, the US is the world leader in wind-sourced production, but it only accounts for 0.8% of it’s national power usage. Despite these disappointing statistics, the US has spent $17 billion on wind power alone in 2008. If this kind of spending is to continue, the US is expected to generate 20% of it’s national electricity through wind-power alone. This is a trend that has occurred in many nations around the globe.

As we continue sourcing our power from non-renewable and environmentally hazardous sources such as plutonium, coal, and natural gas, these materials will become more and more scarce, increasing the price-premium of using these sources as generators of electricity. This necessitates the need for sustainable, alternative forms of energy. Nations have seen the need for this, and as a result have been budgeting to implement more wind farms in opportune places.

Moving forward, there are a few notable countries that will be making even a greater effort to support this renewable energy source: USA, UK, and China, closely followed by Germany, Spain and Denmark (Johnson 2009). These countries are at the forefront not only because they realize the need for renewable energy, but also because their land features admirable conditions on which wind farms can be placed. As mentioned in earlier sections, wind power’s effectiveness is highly based on the location of the wind farm in question.

Overall, the outlook for the future of wind power is an optimistic one. As seen earlier, many countries are making an effort to diversify their power sources, and wind is at the forefront of their thoughts. It is to be expected to see many countries turning to wind power as a major supplemental force in the world of tomorrow.

Works Cited

Carlin, P.W., A.S. Laxson, and E.B. Muljadi. “The History and State of the Art of Variable-
Speed Wind Turbine Technology.” John Wiley and Sons, Ltd. 7 February 2003. 24
June 2011. Web

Drewitt, Allan L. and Rowena H.W. Langston. “Collision Effects of Wind-Power Generators and
Other Obstacles on Birds.” Annals of the New York Academy of Sciences. 2002. 16 June
2011. Web.

Dodge, Darrell. “Illustrated History of Wind Power Development.” TelosNet Web
Development. n.d. 23 June 2011. Web

Kemp, et. Al. “The Offshore Wind Power Debate: Views from Cape Cod.” Taylor and Francis,
Inc. 29 April 2004. 16 June 2011. Web

Sorenson, Bent. “Progress in Wind Energy Utilization.” 31 January 1995. 24 June 2011. Web

Johnson, Jack. "The Future of Wind Power: Perspectives on Global Wind." Renewable Energy World. Renewable Energy Magazine, 19 Feb. 2009. Web. 01 July 2011. <>.

Unlisted. "Denmark's Power Supply." Denmark Board of Power. 09 Oct. 2010. Web. 1 July 2011. <>.

"Benefits of Using Wind Energy - a knol by Wind Turbines." Knol - a unit of knowledge: share what you know, publish your expertise.. N.p., n.d. Web. 1 July 2011. <>.

"Environmental Benefits of Wind Power." MGE. MGE, n.d. Web. 26 June 2011. <>.

"International Energy Outlook 2006." U.S. Energy Information Administration. N.p., n.d. Web. 23 June 2011. <>.

Jacobson, D., and C. High. "Wind Energy and Air Emission Reduction Benefits: A Primer." National Renewable Energy Laboratory. N.p., n.d. Web. 28 June 2011. < >.

"RENEWABLE ENERGY Wind Power’s Contribution to Electric Power Generation and Impact on Farms and Rural Communities." United States Government Accountability Office. N.p., n.d. Web. 26 June 2011. <>.

"RenewableUK - Frequently Asked Questions." RenewableUK - The UK's leading renewable energy association - (formerly named BWEA). N.p., n.d. Web. 1 July 2011. <>.

"Wind Energy Benefits." James Madison University. Department of Energy, n.d. Web. 27 June 2011. <>.

Wiser, Ryan, and Mark Bolinger. "Annual Report on U.S. Wind Power Installation, Cost, and Performance Trends: 2007." NREL. N.p., n.d. Web. 26 June 2011. <>.

"World of Wind - The World's #1 Wind Energy Site! - News - WIND MAJOR ISSUES." World of Wind Energy - Wind Energy Daily News, Events, Companies, Products, Jobs and more . N.p., n.d. Web. 28 June 2011. <>.

Grogg, Kira. "Harvesting the Wind: The Physics of Wind Turbines." Google Scholar. Carleton College, n.d. Web. 1 July 2011. <>.

"The power of multiples: Connecting wind farms can make a more reliable - and cheaper - power source." EurekAlert! - Science News. N.p., n.d. Web. 1 July 2011. <>.

Diesendorf , Mark. "The Base-Load Fallacy ." Australian Sustainability Center. University of New South Wales, n.d. Web. 1 July 2011. <>.

Chih-Yu Lu
Wind power and energy crisis
The reason why renewable energy becomes more important is base on energy crisis. In the past hundreds years, human use coal and fuel and nuclear power as primary energy resource in the modern days. However, those resource are not renewable, which mean they are going to disappear in the following hundred years. On the other hand, those kinds of energy pollute the environment very bad, especially nuclear waste. In order to solve energy crisis, we came out a lot of different ideas to generate more power such as solar power, wind power, hydro power and biofuel.

According to your structure, I think the introduction part took too much space regarding to the whole article. I think it’s more important to focus on future solution of wind power and how to energy crisis. However, the article has great argument about the advantages and disadvantages of wind power. I agreed that wind power is still developing compare to nuclear and thermal power. But in the future, wind power will take more percentage than nuclear and thermal energy. I think it’s better to provide reader more advantages about wind power. In conclusion, you guys have excellent structure about explaining wind power to readers. After reading your article, I felt wind power will make us better life in the future.

Worked sited

Jaeyoon Chung

Wind power is a good alternative energy that is non-pollution, and the resource is infinity, but in the future, the wind power generation will disappear. Wind power is one of the lowest efficiency energy among the natural alternative energy such as hydropower, solar power, and biomass power. Because the wind power generator – windmill – takes up too much space, in the future it might be an issue for increasing population. However, if someone invent a high efficiency and small wind power generator instead of a huge windmill, the wind power generating technology should emerge as a promising alternative energy technology.

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Derek Krueger

One of the overlooked arguing points you could have pressed for could have been that coal and oil will soon no longer exist on this planet. A need for alternative energy, in any form, is needed because no matter what your stance is, oil and coal, the 2 largest worldwide energy providers, will run out in the near future. By some estimates, we will peak production, meaning we will begin using more than we can produce, sometime in the next 40 years( This stance could be used to either say that we can delay this number, which in my opinion is a great point, using wind power because a worldwide switch to alternative energy is unlikely, but delaying it some could help buy some much needed time. Or you could say that we need to stop now, because if we begin to come off oil and coal now, and start using alternative energies like wind and nuclear, we could wind up using all new sources of energy before we are pressed by a lack of oil and coal available.

Howden, Daniel. "World Oil Supplies Are Set to Run out Faster than Expected, Warn Scientists - Science, News - The Independent." The Independent | News | UK and Worldwide News | Newspaper. 14 June 2007. Web. 02 July 2011. <>.

Puloma De

As many benefits there are to wind power there are equally as many disadvantages and even more so than stated in this article. For example, one problem is that there are many better alternatives to reknewable energy that are far more efficiant than wind power and more reliable for government money to be spent on. As stated in the article the amount of energy that wind power generates is not enough to be used by a whole city or even a couple big major buildings, why invest in something that could not sustain city life? One other issue is slightly superficial to most but for people who have lived in the country side and for places that rely on toursim it is quite a problem. It is the fact that wind turbines on the country side are seen as an eyesore, I myself have seen wind turbines when traveling Germany's countryside and was slightly dissapointed to see such large structures obscuring the amazing view across the fields.

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