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Wind Energy as an Alternative

Wind Energy as an Alternative

                                                                                                                                                                                                    Shuainan F., Jing S., Shawn T.

Brief Description of Wind Power

Wind is generated when the sun heats up land, the air around the land will absorb the air and there will be a creation of warmer air. At a particular temperature, the hot air will rise quickly because it is lighter than cool air. Fast air particles will exercise more pressure than the slow moving particles. This means that it will take smaller amounts of hot air particles to maintain the given air pressure at a particular elevation. When the hot air rises due to its lighter mass, the cool air will rush in to fill the gap that the hot air has left. The rush of the cool air is what is known as wind. Using the wind, it is possible to generate electricity that can be used in everyday life as an alternative energy source.

Topic ideas

Main Topic idea: Physics of Wind Power

Sub-topic idea 1: Classical Physics Concepts of Energy, Momentum, and Power

Sub-topic idea 2: Structure of the Turbine and its Significance

Sub-topic idea 3: The Importance of the Generator

Sub-topic idea 4: Inside a Generator

Sub-topic idea 5: Magnetic Force and Electromagnetic Force

Societal Implications

This type of alternative energy is very reliable for energy consumption in the long term, as wind is a resource that will is infinite and renewable. This type of energy generation is much more sustainable than fossil fuels as it does not pollute the environment or produce radioactive or toxic waste. Despite the cost of installation of a wind turbines, wind energy is much more economic than fossil fuels. Wind power may cost a slight bit more than fossil fuel generated power, but it much better for the environment. In more windy areas, there is sometimes so much power generated, that it is possible to sell energy back to the power company!

Wind energy is not only reliable, but it is pollution free, and is cost efficient. It can take as little as one efficient wind turbine to generate enough energy to power an entire household.

Topic 1 Classical Physics Concepts of Energy, Momentum, and Power

Wind Energy is a form of energy that involves using a wind turbine as an electric generator to convert the kinetic energy of the wind to electric energy. Wind turbines consists of a rotor comprised of three blades. These components are placed on a pole with an average height of 20 meters from the ground. Generally, the higher the rotor is placed, the stronger the wind gusts are. In order to optimize the output of the wind, three factors need to be considered. Stronger wind means a wind with higher speed and force; this means that more power will be generated.

 

 

From the formula Ek = ½ mv2 , it can be seen that speed and kinetic energy are directly proportional. When there is more speed, there will be a greater kinetic energy. Using the formula: P = E/t, when there is more energy, power (energy/second) will also increase. This is because energy is directly proportional to power. Therefore a higher velocity will result in more power being generated.

Another factor that will increase the output of energy is the size of the turbine rotor and blades. A larger rotor and blades means more mass. Using the momentum formula: p = mv, mass is directly proportional to momentum. This means that the greater the mass of the motor, the greater the momentum of the motor, Ft = p.

Since momentum and time are directly proportional, an increase in momentum would result in an increase in time. Thus, a turbine of more mass would spin for longer even without wind continually driving it.  P = E/t , hence Pt = E.

From this formula, time and energy are directly proportional, the longer the turbine is spinning, the higher its energy output.

 Topic 2 Structure of the Turbine and its Significance

The structure of a wind turbine plays a crucial role in the functionality and workings of wind power. Not only does the wind need to be able to turn the blades, but the whole process must be made efficient, so as to generate maximum amount of energy possible. This way, not only is wind power a clean alternative to coal and other hydrocarbon combustion processes, but it is also at least comparable to, or beats the 40% efficiency of a thermo-electric power plant that runs off of hydrocarbons.

The structure of a wind turbine can be summarized in the following diagram:

shawn1

Figure 1: Parts and components of a wind turbine

The process of generating power with a wind turbine is identical to the process used by hydrocarbon combustion. They both use a generator, and an external source of energy to turn the generator. The only difference is the type of energy input used. With hydrocarbons, the energy input starts off as the chemical energy stored in bonds between atoms in fossil fuels such as coal and natural gas. When these substances are combusted (reacted with oxygen), the chemical energy gets converted to thermal energy. This energy then is transferred to water molecules, boiling off the water as steam, which in turn drive a steam turbine attached to a generator. At this point, the chemical energy of the hydrocarbon fuel source is now the kinetic energy of the steam turbine, which in turn gets converted to electrical energy via the generator. Wind power however, undergoes less energy conversions, and is therefore a much more simple set of steps.

Simply put, a wind turbine is a generator attached to a set of blades, and a rotor. The blades are angled in such a way that when wind blows on them, the kinetic energy of the fast-moving air molecules is transferred to the blades and rotor of the turbine, causing the turbine to spin. Because the rotor of the turbine is linked to the generator via a system of shafts and gears (as seen in the diagram above), the generator gets spun, converting the kinetic energy of the wind turbine into electrical energy.

 Topic 3 The Importance of the Generator

The generator (structure 7) is the heart of the wind turbine. Without this amazing piece of machinery, the turbine is not much more than a tall, metallic pinwheel. While it is obvious what the generator’s role is, what is it exactly that allows this piece of equipment to operate? The answer requires looking into the inner workings of the generator, and concepts of electromagnetism that contribute to the technology that drives this powerful machine.

 Topic 4 Inside a Generator

A generator has the exact same structure as a motor. The only difference between the two is the input and output energies. Whereas in a motor the input energy is electricity and the output is kinetic energy, a generator requires an input of kinetic energy and supplies an output of electricity. There are two types of generators as there are motors (alternating current, or AC, and direct current, or DC). Typically, when it comes to an application that is as large as electricity generation for a large area (such as big-scale wind farms in the countryside do), the generator type is AC. A personal-sized wind turbine however, such as the ones used by people in their backyard, usually contains a DC generator.

shawn2

Figure 2: The inside parts of an AC generator.

The generator is composed of a set of magnets to provide the magnetic field and magnetic force required to move electrons (i.e. create a current flow), a set of spinning coils in the magnetic field, where the current is initiated, slip rings, which are linked to wires carrying current out of the generator, and brushes, which allow the slip rings to contact the wires while not disturbing the spinning of the wire coil. A spindle is then attached to the generator along the axis of rotation, to allow the generator to be spun. A DC generator is very similar, with only a minor difference in terms of structure – instead of slip rings, it contains a split-ring commutator:

shawn3

Figure 3: The insides of a DC generator.

Combining only these relatively simple few structures together (but there may be many of one structure), and an external force to turn the spindle of the generator, large, high-output wind turbines are made capable of cranking out power at rates of  up to 50 kilowatts (50 000 watts)! How is it that these few simple structures allow such a big achievement?

Topic 5 Magnetic Force and Electromagnetic Force

Magnetic force and electromagnetic force are the two principles that allow the generator to perform its task. Imagine the classical experiment from science class of thrusting a bar magnet into a coil of wire that is hooked up to a galvanometer. What do you observe? The needle of the galvanometer suddenly jumps, indicating that there is current flowing through the wire. Hence, this is named the generator effect, and the current is an induced current known as electromagnetic force. The generator of a wind turbine (either AC or DC) operates using the same principle.

Looking back to figure 2 of the AC generator, the open left-hand rule can be applied to the generator. To do this, select one half of the coil that is moving in a specific direction. Then, point the fingers of the left hand in the direction of the magnetic field (from the north pole to the south pole), and the thumb in the direction the wire coil is moving. The outward direction the palm is now facing is the direction of the magnetic force, the force that pushes electrons in the atoms of the wire. Because the wire is made of metal, and metallic atom nuclei have very weak holds on their electrons, the magnetic force can easily push electrons in a certain direction in the wire. Since the halves of the ring are moving in opposing directions, the current induced in the parallel sections are in opposing directions. Because it is connected at the top, the overall current is in the same direction, and an electric current them flows in the wires attached to the slip ring brushes. But where does the alternating current kick in?

Since the generator is obviously not going to keep switching its direction of spin, and neither is the magnetic field, the magnetic force must change in order to create the alternating current. Look closely at the diagram, and use the open-left hand rule. As soon as the generator makes a half-way spin and now the loop halves have switched spots, the magnetic force in each half is in the opposing direction as what it was when the loop was on the other side. This causes electrons to continuously switch their direction as they get pushed around by the magnetic force generated. Hence, alternating current has no fixed direction, and electrons continually flow back and forth in a wire.

So, what prevents the same thing from happening in a DC generator then? During the switch where the two wire coils end up on opposite sides, the split-ring commutator prevents the brushes from contacting anything at all. And when the switch is complete, each brush is contacting the piece of the commutator that the previous brush was contacting. This ensures that the part of the wire coil that is on the right side (magnetic force in a certain direction) at the moment will always contact the wire that is attached to the right side, and the part of the coil on the left side (magnetic field in another direction) always contacts the wire attached to the left. Therefore, no such reversal in current occurs, and a direct current is generated.

Topic 6 Why Alternating Current?

A common question is, why is alternating current used for large-scale electricity generation, if most appliances use direct current? The answer is related to the efficiency of transporting a current over a long distance. Since it is obvious that the energy is going to be lost due to resistance of the wire it is transported over, it is desirable to minimize this loss as much as possible. To maximize efficiency, the voltage of the electricity must be stepped up. A property of alternating current that direct current lacks is its ability to be stepped up or down in terms of voltage. This is not only useful to make transporting over long distance efficient, but also allows the voltage to be adjusted accordingly before it is used.

 Conclusion

Clearly, wind energy is advantageous in terms of eco-friendliness and in terms of costs, due to its relative simplicity and its rather high output. Of course, there are drawbacks with wind energy, as there are with anything, but there are many more advantages than there are drawbacks. So why not choose it over other forms? Converting to wind energy is a breeze!

 References and Citations

  • Alternative Energy. (2009, July 24).What factors affect the output of wind

turbines? Retrieved December 29, 2012, from http://www.alternative-energy-news.info/what-factors-affect-the-output-of-wind-turbines/

  • howstuffworks. (n.d.).  How Wind Power Works. Retrieved December 29, 2012,

from http://science.howstuffworks.com/environmental/green-science/wind-power.htm

  • The Electricity Forum. (2012). Wind generated electricity. Retrieved December

29, 2012, from http://www.electricityforum.com/wind-generated-electricity.html

  • The Marsmen Website. (2005). How do Wind Turbines Work? Retrieved

December 29, 2012, from http://marsmen.webs.com/windpoweronmars.htm

  • Tutor Notes. (2011). AC Generator – Electromagnetism. Retrieved January 2,

2013, from http://www.tutornotes.com.hk/ac_generator/

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Alternative Energy Project

            Wind Farms, It’ll blow you away.

                                                                                                            Daniel T, Matthew B

                                                                                                                                                                      2012-01-06

In society today, fuel has become less desirable due to its harmful effects on the world. It now leads in alternative energy sources by two common methods : electricity by generator effect as well as electricity by photoelectric effect. Some examples of electricity by generator effect involve hydroelectric dams, wind farms, or nuclear power plants, compared to electricity by photoelectric effect which involves solar panels. A key element for an alternative energy source that is being currently being improvised world-wide is wind farms.  As the utilization of wind energy has increased in recent years, there has been an annual increase in installed capacity of around 20%. For example, the 38 GWe (GWe is the gig watts of electric energy produced by wind turbines in the location) increment in 2010 represented an investment of EUR 47 billion, which is equivalent of 65 billion in US dollars, and was followed by 41 GWe increase in 2011. Which brought  the total world wind capacity up to 238 GWe, with tens of thousands of turbines in operation? Currently, wind turbines of up to 6 MWe are now functioning in many countries around the world. China leads the field with over 62 GWe installed, US with 47, Germany with 29, Spain with 21.5GWe, and India with 16 GWe at the end of 2011. The largest wind farm is that of the Forewind for the Dogger Bank in the North Sea, producing around 7.2GWe, which will supply the UK with some 25 billion kWh/year. Today, Denmark is the most intensely wind-turbined part of the planet with 1.74 per 1000 people- 4700 turbines totaling 2315 mWe, 1800 MWe of which have priority dispatch and power .

daniel1

Figure1. Graph showing the increased purchase of wind turbines in Denmark

(http://energy.saving.nu/windenergy/history.shtml)

Wind turbines ranges from class 1 which are the lowest to class 7 with are the highest. Wind turbines consist of a few basic components: a rotor( the part that rotates in the wind), an electrical generator, a speed-control system, and a tower.

daniel2

Figure2. Wind farm with several hundred wind turbines in motion

(http://blogs.telegraph.co.uk/news/files/2012/02/wind-turbine-2.jpg)

daniel3

Figure3. Parts of a wind turbine

(http://www.therockatbc.com/wp-content/uploads/2012/02/Wind-Turbine-Diagram.gif)

(http://www.canadiangeographic.ca/magazine/oct12/nwt_diamond_mines_wind_power.asp)

In the above electronic article “Wind Power, energy gem”  wind power is fueling the push to green diamond minds in the Northwest Territories. In the Northwest Territories there are currently four towering wind turbines which are 99 m tall, these wind turbines were installed by a mining corporation known as Rio Tinto at the Diavik Diamond Mine and are scheduled to be operational near the early fall. This is the first industrial use of wind power in a mining operation in the world as stated by Wade Carpenter, the territorial government alternative-energy specialist.

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Figure 4. Rio Tinto Diamond Mines in Canada

(http://www.bdlive.co.za/world/americas/2012/12/04/news-analysis-cleaner-power-for-a-dirty-industry)

Societal Impact: The societal impact of the wind turbines is that prior to the creation of the wind turbines in the Rio Tinto at the Diavik Diamond Mine, the mine was being powered entirely on diesel fuel. Many problems came from the use of such fuel, as they had to be trucked up with winter ice and then driven to the roads of the mine; but when the warm temperatures melted the roads, the mines had to fly in fuel, increasing the greenhouse-gas emissions given off by the Northwest Territories by a staggering amount of 60 percent since the onset of diamond mining which had occurred 20 years ago. To solve this issue, the Diavik’s wind-diesel hybrid system was incorporated as the system would reduce the carbon dioxide emissions by approximately six percent. The wind turbines reduced the annual diesel consumption by four million litres, or 100 truckloads as stated in the article- which would save the Diavik $6 million a year at today’s fuel prices. Among the Rio Tinto at the Diavik Diamond Mine, wind turbines allowed people to avoid external or societal costs associated with conventional resources, namely, the trade deficit from importing foreign oil and other fuels, less pollution to the environmental cost of pollution, and the cost of depleted resources. Wind powered turbines offer renewable energy forms, as well as it having no cost and being a renewable resource, there will always be the same amount in the future as it is as stated renewable, as it is a clean source.

Among that, many countries that have implemented wind turbines like the UK , Germany , and Denmark have seen abundant amounts of energy produced , for example in  Germany, it was reported that between 6 and 8% of the total capacity of the wind was usable, resulting in a total of 14.5 GWe of energy for Germany. Keep in mind that one megawatt or MW can supply electricity to approximately 240 to 300 households per year, so the amount of households that could be supplied by 14.5 GWe of energy form wind turbines is immense.

Also the pros of wind turbines as stated are that wind energy is a free, renewable resource, clean non-polluting, they emit no air pollutants or greenhouse gases for example, in the U.S department of Energy in 1990, California’s wind power plants offset the emission of more than 2.5 billion pounds of carbon dioxide and 15million pounds of other pollutants that would’ve produced otherwise if California had used fossil fuels. Remote areas that are not connected to the electricity power grid can use wind farms to provide for their own energy, and wind turbines play a role in both the developed and third world. Wind also compares more favorable with the costs saved on fuel from fossil generators.

Some cons of the wind turbine are: that the strength of the wind is not constant and it varies from zero to an abundant force via a storm, the amount of energy produced will vary, wind turbines are noisy, and may cause harm to the animals that live in the location. But most of these cons are not being solved.

As wind turbines are located in areas that experience high average wind speeds, and that are distant from areas of electricity demand. New technology has improved to diminish the noise created from wind turbines. Under most conditions, modern turbines are quiet.

Physics Implication: The use of wind turbines in wind farm incorporates the physic concept of kinematics. Wind energy is the kinetic energy of moving air generated by high winds, the kinetic energy of a mass m and the velocity of that mass, v, can be summarized in the formula:  “ Ekin=1/2mv2” . Since air mass , m, can be determined from the air density , p, and the air volume, v , according to m=pV, then Ekin,wind=1/2Vpv2.

Power is the energy divided by time, time which is used as (delta) t, travels a distance which is velocity multiple by time, v (delta) t, which is then multiplied by the distance with the rotor area of the wind turbine, resulting in the volume ((∆V=A(∆t)(v)  which drives the wind turbine for the set period of time.  Since we know daniel equation1

we can  determine the power generated by wind.

With this formula we can see that wind power increases with wind speed, for example, doubling the wind speed gives eight times the wind power. This is why locations where wind occurs more frequently are prime locations for wind turbines to be set up at, but the effective useable wind power is less than indicated by the equation.

This is, because given that the wind speed behind the turbine cannot be zero, since no air can follow, the result is that only a part of the kinetic energy being able to be extracted.

Given this diagram:

daniel5

Figure5. Diagram of two turbines, http://uni-leipzig.de/~energy/ef/15.htm

It is indicated that the wind speed in the second turbine is larger compared to the wind speed in the first. This is because the mass flow must be continuous, resulting in the area of the second turbine to be bigger than the first. The effective power is the difference between the two wind powers, which can be deprived using

In the case that the difference of both wind speed is zero, there is no net efficiency, and where the difference is too big, the air flowing through the rotor is too greatly hindered.

Wind turbines located too close together would be driven only by slower air. Therefore wind turbines would need a minimum distance of eight times the rotor-diameter for them to work with an efficient amount of air.

Turbines have lost one blade and now use three blades, due to the rotor power, which is proportional to the torque (M) acting on the shaft, and the rotation frequency (n).  The torque (M) increases with the number of blades, however, every blade, as it rotates, reduces the wind speed known as the wind shadow. The wind shadow increases with the number of blades, which means the optimal tip speed ratio is achieved when three blades are used.

daniel6

daniel7

Figure6. Four bladed wind turbine                                                             Figure7. Three bladed wind turbine

(http://www.chegg.com/homework-help/questions-and-answers/physics-archive-2011-april-06)

(http://indianapublicmedia.org/amomentofscience/wind-turbines-have-three-blades/)

Wind Turbines continue to prove to be a successful and efficient alternative energy source in today’s society. Given the successes of wind turbines in countries like the U.S, Denmark, U.K, and Germany, it can be said that wind farms and wind turbines can essentially become an important source of energy in the world. As the wind turbine industry continues to be fastest growing power source worldwide. “http://www.nature.com/news/the-trouble-with-turbines-an-ill-wind-1.10849

References:

Websites:

. 2013. . . . [ONLINE] Available at: http://windeis.anl.gov/documents/docs/WindFAQ21Jun05.pdf. [Accessed 07 January 2013].

Renewable Energy and Electricity | Sustainable Energy | Renewable Energy. 2013. Renewable Energy and Electricity | Sustainable Energy | Renewable Energy. [ONLINE] Available at: http://www.world-nuclear.org/info/inf10.html. [Accessed 07 January 2013].

What are the Benefits? – Wind Energy and Wind Facts – CanWEA. 2013. What are the Benefits? – Wind Energy and Wind Facts – CanWEA. [ONLINE] Available at: http://www.canwea.ca/wind-energy/index7_e.php. [Accessed 07 January 2013].

Advantages and Disadvantages of Wind Power. 2013. Advantages and Disadvantages of Wind Power. [ONLINE] Available at: http://www.technologystudent.com/energy1/wind8.htm. [Accessed 07 January 2013].

Main Article:

An energy gem – Canadian Geographic. 2013. An energy gem – Canadian Geographic. [ONLINE] Available at: http://www.canadiangeographic.ca/magazine/oct12/nwt_diamond_mines_wind_power.asp. [Accessed 07 January 2013].

Images:

Physics Archive | April 06, 2011 | Chegg.com. 2013. Physics Archive | April 06, 2011 | Chegg.com. [ONLINE] Available at: http://www.chegg.com/homework-help/questions-and-answers/physics-archive-2011-april-06. [Accessed 07 January 2013].

Why Do Wind Turbines Have Three Blades? | A Moment of Science – Indiana Public Media. 2013. Why Do Wind Turbines Have Three Blades? | A Moment of Science – Indiana Public Media. [ONLINE] Available at: http://indianapublicmedia.org/amomentofscience/wind-turbines-have-three-blades. [Accessed 07 January 2013].

Physics of Wind Turbines; Energy Fundamentals by R. Snurr and D. Freude, . 2013. Physics of Wind Turbines; Energy Fundamentals by R. Snurr and D. Freude, . [ONLINE] Available at: http://uni-leipzig.de/~energy/ef/15.htm. [Accessed 07 January 2013].

. 2013. . [ONLINE] Available at: http://www.therockatbc.com/wp-content/uploads/2012/02/Wind-Turbine-Diagram.gif. [Accessed 07 January 2013].

2013. . [ONLINE] Available at: http://blogs.telegraph.co.uk/news/files/2012/02/wind-turbine-2.jpg. [Accessed 07 January 2013].

Energy Saving Now!. 2013. Energy Saving Now!. [ONLINE] Available at: http://energy.saving.nu/windenergy/history.shtml. [Accessed 07 January 2013].

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Claire Y., Jeff M., Diego S.

June 8th, 2012

Selected Article:  “Can the progress continue?”

http://www.windpowermonthly.com/news/1134082/progress-continue/

The Physics Behind Wind Energy

 What is wind?

 Wind is the flow of gases on a very large scale. Wind is caused by the differences of pressure in the earth’s atmosphere. Wind is caused by two major factors on the planet earth. The first being the sun and the second being the rotation of the planet. The sun does not heat up the earth’s atmosphere evenly, as most of the solar energy is absorbed at the equator. When the air becomes heated it expands creating an area of higher pressure. Diffusion causes this area of higher pressure to move to an area of lower pressure. On a very large scale this would massive amounts of air to travel from one area to another, creating vast amounts of kinetic energy that can be harnessed by humans through the use of a wind turbine.

The physics of a wind turbine

A wind turbine is used to harness the kinetic energy of vast amounts of wind, and transform it into electricity. This can be shown with a very simple calculation. First we need to remember that wind is an air mass moving from an area of high pressure to an area of low pressure. This movement of air is kinetic energy and can be shown by the formula:

 Ek = ½ mv2

Ek = Kinetic Energy

m = Mass

v = Velocity

 How do we determine the mass of air?

We must first view the air moving through the wind turbine as a segment shaped like a horizontal cylinder.  The energy in it depends on the volume of air, density, and wind speed. The mass per unit time for a slice of the cylinder is:

M = ρAV

M = mass
ρ= density
A = area
V = wind speed

 Formula for kinetic energy of wind

This mass can now be substituted into the formula for kinetic energy to give us the equation:

 Ek = ½ ρ Av3

Therefore the amount of energy in the wind is controlled by the density, surface area and velocity of the moving air. This equation shows that selecting an area of high wind velocity is the most crucial part of picking out an area to place a wind turbine.

Efficiency

In reality, the equation for kinetic energy of wind does not represent the amount of energy that a wind turbine is able to harness. Wind turbines are not 100% efficient, and are unable to convert all of the kinetic energy into wind. If a wind turbine was 100% efficient then wind speeds would drop to 0 km/h after passing through the turbine.  Albert Betz published a book in 1926 that showed it is only possible to extract 16/27 or 59% of the energy from a wind turbine. This is called Betz’ law. Therefore the theoretical energy model for a wind turbine is:

Ek max = (16/27) (½ ρ Av3)

 The Societal Implications of Wind Energy

 Negative perspectives regarding wind turbines

It must be noted that there is a generally negative attitude towards wind turbines being located in communities.  While most would agree that wind turbines are an excellent source of electric energy, hardly any would advocate for one being built near their own neighbourhood, due to the impact that wind turbines have on the surrounding environment.  One of the most significant of these impacts is noise pollution – the noise made by a wind turbine is similar to that of a small jet engine.  Noise pollution is not only a living disadvantage, but is an economic disadvantage as well as it can lower real estate values.  This is compounded as wind turbines are also considered to be a form of visual pollution.

Perhaps the most major impact of wind turbines is with respect to wildlife impact.  While wind energy is certainly classified as a clean form of energy and in that regard is very environmentally friendly, wind turbines can create many problems for wildlife.  Birds and bats have been found at the bases of wind turbines, dying immediately upon contact with the blades.  This is not the only way in which wildlife can be harmed – the construction itself of the wind turbines requires a rooted foundation, often destroying underground habitats as well as interfering with surrounding ones.

Social acceptance of wind energy

Despite the various negative consequences and social concerns regarding wind turbines and wind energies, it is without a doubt a form of energy that tackles the issues of energy supply and climate change.  Generally speaking, there is a very positive outlook on wind energy and recent scientific and technological advancements in the field have strengthened public favour.  The problem regarding birds and bats has been combated with the implementation of slow blades, and the elimination of unnecessary overhangs that can potentially be used as resting areas. Wind energy is an inexpensive and relatively consistent alternative to other energy generators.  It is an extremely promising source of energy, and one that is becoming more and more relevant to our world.

 References

Clean Energy Ideas. (2007-2012). A Wind Turbines Impact On The Surrounding Environment. Retrieved June 8, 2012, from Clean Energy Ideas: http://www.clean-energy-ideas.com/articles/wind_turbines_impact.html

Lago, C., Prades, A., Oltra, C., Lechon, Y., Pullen, A., & Auer, H. (2007-2009). The Social Acceptance of Wind Energy: An Introduction to the Concept. Retrieved June 8, 2012, from Wind Energy The Facts: http://www.wind-energy-the-facts.org/en/environment/chapter-6-social-acceptance-of-wind-energy-and-wind-farms/

Norz, C. (2009, September 17). The Physics and Economics of Wind Turbines. Retrieved June 7 , 2012, from Windpower Engineering & Development: http://www.windpowerengineering.com/policy/the-physics-and-economics-of-wind-turbines/

 Images

http://www.globalwindgroup.com/wp-content/uploads/2011/01/horizontal.jpg

http://drscoundrels.com/wp-content/uploads/2011/03/texas-wind-farm.jpg

http://wpcore.wpe.s3.amazonaws.com/wp-content/uploads/2009/09/Feature-1-Graph1-300×190.jpg

http://wpcore.wpe.s3.amazonaws.com/wp-content/uploads/2009/09/Feature-1-Prices.jpg

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A Windy Alternative

Source: http://www.powerscorecard.org/tech_detail.cfm?resource_id=11

Source Summary

Wind energy is the fastest growing form of energy. As wind is inexhaustible, it makes for an ideal source of perpetual energy. Turbines transform the kinetic energy of moving air into kinetic energy in the rotating blades, which is then transformed into electricity by the rotors installed inside the turbine. Regions where winds reach a speed of 12 miles per hour are the most ideal sites for the creation of a wind farm.

Concepts of Physics Involved

Kinetic Energy into Electricity:

As the blades on a wind turbine is turned by the wind, the generator, which is connected to the blades, converts mechanical power into electricity. Through the application of generators in turbines, electricity is then produced. Generators operate according to the principle of electromagnetic induction as proposed by Michael Faraday 1831. This principle states that when an electric conductor is put into motion and is exposed to a magnetic field, it creates a continuous flow of energy that produces electricity. In turbines, kinetic energy is used to turn the conductor which is fitted between two opposite magnetic fields thus producing electrons, which are then emitted as electricity to be used.

Social Implications of Wind Energy

Wind energy has no drawbacks as an energy source; however, it is very loud, takes up living space for wildlife, and is not really a pretty sight. People living in the vicinity may or may not approve of these in their surroundings as they signify both clean and efficient power, but also ruin the natural scenery. Wind turbines are notoriously loud. They make as much noise as your average washing machine. Although the sound can be controlled, it cannot be completely eliminated. Originally, the decimation of surrounding bird populations was a severe source for concern, but this problem has been corrected through the development and use of new turbines; slower rotations of the blades, less protrusions to prevent birds from perching on them, and identifying locations where less bird populations reside.

References

Rachel Nall, How Do Generators Make Electricity? Retrieved on June 7, 2011, From:

http://www.ehow.com/how-does_5163045_do-generators-make-electricity.html

Energy Efficiency and Renewable Energy, How Wind Turbines Work, Retrieved on June 7, 2011, From:

http://www1.eere.energy.gov/windandhydro/wind_how.html

Christine and Scott Gable, How do Motors and Generators Work, Retrieved on June 7, 2011, From:

http://alternativefuels.about.com/od/hybridvehicles/a/motorgenerator.htm

Images From:

http://hawaii.gov/dbedt/info/energy/renewable/electricitygeneration/motor-eout.gif

http://www.techienation.com/wp-content/uploads/2008/08/how_wind_turbine_works.jpg

Carl G & Cindy D

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The power of wind

                            Over the years, there has been a huge controversy over how humanity is burning up all of the resources that we need to survive. Alternate sources of energy have been found, and people look for ways to incorporate these in everyday life. We have the options of solar, biomass, wind, tidal and nuclear. The main problem is solely these energy sources can be expensive, while others can cause problems to get. One of the Alternatives energy sources that we use in today’s modern society is wind power. Wind is a natural occurrence that can in the end change the ways that we get energy.


                          Wind energy is defined as the “power generated by harnessing the wind, usually by windmills”. In a science text book it is a terms used to state that  wind energy is the force of winds blowing across the earth’s surface. Wind is caused by uneven heating on the earth’s surface.That heat tries to move from hotter to colder regions. Wind energy is usually associated with wind turbines/windmills, but there are other similar concepts out there, like Floating air turbines.The idea of using wind energy was first used hundreds of years ago ago, when early windmills were used to power millstones and pumps.When harnessed, wind energy can be converted into mechanical energy for performing work such as pumping water, or grinding grain. The amount of kinetic energy within Earth’s atmosphere is equal to about 10,000 trillion kilowatt-hours.

One of the problems is the amount of noise a wind turbine makes but engineers have suggested offshore locations, where wind speeds are higher and the impact of visual pollution is dramatically reduced.

Some of the advantages of wind power include:

  • Wind energy is free, clean and non-polluting. The generation of wind power does not produce any by-products that could be harmful to the environment. There are no chemicals involved, no waste production, it’s  clean and environmentally friendly.
  • Wind supply is plentiful, so wind energy is a renewable supply.
  • Suitable for less sunny regions. This creates the possibility of generating energy non-stop, during day and night.
  • Dovetails well with other systems. The generated wind energy can be used full time in residential or commercial applications combined with your regular power supply.
  • Simple technology. There is nothing too complex, mechanically, in terms of designing and building wind turbines.
  •  Cheap electricity.  Wind energy is relatively cheap as compared to other sources.
  • Safe, if properly maintained.

DID YOU KNOW THAT IN ALBERTA,  THERE ARE:

  • 24 WIND FARMS
  • 514 WIND TURBINES
  • 653 MW INSTALLED CAPACITY
  • AND A 0.1 TW-h GENERATION

as of July 31,2010,( referenced from the Sustainable and renewable energy booklet).

Alberta has been a pioneer in wind production in Canada and plans to install over 7,670 more generator capacity wind projects to produce over7800MW of energy.some of the corporations doing this include Trans Alta, Enbridge, Suncor, Enmax, Shell, Alberta Wind Energy Corporationand Greengate power Corporation.

Overall, Wind energy is an amazing alternate versus others as it gives us more power than hydro-electricity, or biomass, or other alternative fuels! It is also more environmentally friendly as just uses nature to fuel us without release emissions or harming the environment.

Tania L. and Tatum M.

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Electricity Generation by Wind

Mark H

Wind power is slowing becoming the driving force in today’s power struggle, and many countries around the world are slowing adapting to the changing times. Unlike burning fossil fuels, wind power is cheap, has no environmental impact, and is becoming more practical for generating power to a large number of consumers. All of the wind turbines installed globally manufacture enough energy to meet the electricity needs of the United Kingdom, which is comprised of 60 million inhabitants and is the sixth largest economy in the world.
Wind Turbines

The design for a wind turbine is very simple, yet still maximizes the power output. It is comprised of three blades mounted to a rotor which is at the end of a long shaft. In some cases more blades can be attached to the wind turbine; however the cost to do so is generally not worth the extra power. Modern wind turbines range from forty to eighty meters high, and have a fifty to eighty-five meter span. The physics concepts like the design are also relatively simple. Wind, which is created when the sun’s rays unevenly heat up the atmosphere, forces the airfoil shape blades to rotate. When the edge of the airfoil is angled very slightly out of the direction of the wind, the air moves more quickly on the upper side creating a low pressure that essentially lifts the airfoil upward, helping turn the blades.  The blades are connected to a central shaft which is connected to various gears turning a generator. A generator takes mechanical energy and turns it into electrical energy by forcing electrons to flow through an external circuit. Momentum is always conserved, because the force from the wind is transferred to the blades. Momentum also plays a role in the actual movement of the blades as well, so more force is required to make the blades begin to spin. From Newton’s third law, this force on the wind is equal to and opposite of the thrust. However, since no system is perfectly efficient some energy is lost due to friction within the turbine. Put simply the faster the wind blows the faster the blades will spin, turning the central shaft, and producing more electricity.  This is also one of the limitations of wind power, since it is dependent on the environment’s weather patterns.
Wind Turbine Internal Parts

There are many social implications to wind turbines, to begin; they are the most inexpensive form of electricity on a large scale. Also there are absolutely no environmental problems associated with the use of wind turbines. Another benefit of the wind turbine industry is the fact that approximately 670 000 people are employed worldwide, both directly and indirectly in various sectors of the wind community. It can be observed that desire for investment in wind power is strong and many projects are expected to come. In 2015, a global capacity of 600 000 MW is possible. By the end of year 2020, at least 1 500 000 MW can be expected to be installed globally.
Total Installed Wind Capacity 1997-2010

References

Article – http://www.wwindea.org/home/images/stories/pdfs/worldwindenergyreport2010_s.pdf

Concepts –

http://www.clean-energy-ideas.com/articles/how_do_wind_turbines_work.html

http://www.greenlivinganswers.com/wind-power/how-does-a-wind-turbine-create-electricity

Pictures –

http://www.google.ca/imgres?imgurl=http://investmentsinenergy.com/wp-content/uploads/2010/12/wind_turbine.jpg&imgrefurl=http://investmentsinenergy.com/ge-1-5-sl-wind-turbines-for-sale/&usg=__40s4FMByf5-YklWcgfUTS3wsvd8=&h=300&w=400&sz=27&hl=en&start=0&zoom=1&tbnid=TtrTCxJPc3_94M:&tbnh=163&tbnw=245&ei=5t3uTcqKGofliAKXtIDrAQ&prev=/search%3Fq%3Dwind%2Bturbines%26um%3D1%26hl%3Den%26sa%3DN%26biw%3D1419%26bih%3D699%26tbm%3Disch&um=1&itbs=1&iact=rc&dur=343&page=1&ndsp=19&ved=1t:429,r:1,s:0&tx=98&ty=105

http://www.google.ca/imgres?imgurl=http://www.alternative-energy-news.info/images/technical/wind-turbine.jpg&imgrefurl=http://www.alternative-energy-news.info/technology/wind-power/wind-turbines/&usg=__S7CuPg5wlfaeMmGZN2sKFZUqb8M=&h=476&w=500&sz=88&hl=en&start=0&zoom=1&tbnid=hA6Ooyz2pGeDPM:&tbnh=163&tbnw=171&ei=5t3uTcqKGofliAKXtIDrAQ&prev=/search%3Fq%3Dwind%2Bturbines%26um%3D1%26hl%3Den%26sa%3DN%26biw%3D1419%26bih%3D699%26tbm%3Disch&um=1&itbs=1&iact=rc&dur=187&page=1&ndsp=19&ved=1t:429,r:0,s:0&tx=92&ty=35

http://www.wwindea.org/home/images/stories/pdfs/worldwindenergyreport2010_s.pdf

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June 7, 2011

By Anshini S and Vicky C

The dawn of the millennium has brought with it an exciting series of developments and progress. One of the most important developments made is the research of alternative methods of energy. One of the most widely known and appreciated sources of alternative energy is wind power. Wind power harnesses the energy of the wind. The kinetic energy of the wind is converted into electrical energy by turbines. The size of the turbine normally varies, the bigger the  surface area, the more energy produced.

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wind turbine

The physics concepts behind wind power can be related to

“The Generator Effect”

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A diagram of the function of a wind turbine

(where a change in magnetic field induces a current). When the wind hits the rotors of the wind power, it causes a shaft that is connected to it to spin. The shaft is connected to an electric generator that consists of electromagnets that are placed within coils of wire. The mechanical energy of the spinning shaft induces a changing magnetic field within the coils of the generator,which in turninduces voltage.

Thus, the mechanical energy of the wind is transformed into electricity. The amount of electricity that is produced by generators is dependent upon the rotation frequency of the rotors. There are two types of generators:

synchronous and asynchronous. The synchronous generator operates at the same speed as the turnings of the rotor, while asynchronous generator operate at a slightly different speed than that of the rotor.

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A wind farm

The challenges of climate change and environmental concerns have caused a growing interest in alternate forms of energy. Wind power is a viable and effective form of energy. Wind energy does not create any pollution and uses a renewable source of energy, thus slightly reducing the dependency of fossil fuels. Wind energy is a relatively cheap source of energy as well compared to other energy forms, making it more accessible to people. Another advantage of wind energy is that it is an available resource for people in all parts of the world. However concerns have arisen over the impact wind farms have caused towards wildlife. It is common for birds to get killed while flying too close to the rotors. Another disadvantage is that wind farms have been known to get damaged from lightning, causing huge losses of money. Complaints have also risen over the noise pollution of the wind farms, and over their unreliability. The wind is unpredictable, so critics have said that it is not the most practical source of energy to use on a long term basis.

However, despite the pros and cons, wind energy has proved to be a popular source of alternative energy, and will help contribute to efforts towards a cleaner, fossil-fuel free world.

References:

A wind farm. Retrieved June 7, 2011 from the internet.

www.free-energy-now.us

Wind turbine. Retrieved June 7, 2011 from the internet.

www.apps.carleton.edu

Diagram of Wind Turbine. Retrieved June 7, 2011 from the internet.

http://interestingengineering.blogspot.com/2011/04/wind-power-generator.html

Home Power Generation from the wind. Retrieved June 7, 2011 from the Internet.

http://windpower.generatorguide.net/

The Physics and Power of Wind Turbines. Retrieved June 7, 2011 from the Internet.

http://www.windpowerengineering.com/policy/the-physics-and-economics-of-wind-turbines/

Kira Grogg. (2005) Harvesting the Wind: The Physics of Turbines. Retrieved June 7, 2011 from the Internet.

https://dspace.lasrworks.org/bitstream/handle/10349/145/fulltext.pdf?sequence=2

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