Wind Power Joshua Lee, Yuree Chu

Wind Energy? Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetative cover. Such flow can be harvested by modern wind turbines. When so, this natural energy resource can be transfered and genergated to be used as electricity.

What is wind power? Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electrical power, windmills for mechanical power and so on.

Basic info

History of Wind Power Wind power has been used as long as humans have put sails into the wind. For more than two millennia wind-powered machine have ground grain and pumped water. Wind power was widely available and not confined to the banks of fast-flowing streams, or later, requiring sources of fuel. Later in history, with the development of electric power, wind power found new applications in lighting buildings remote from centrally-generated power. Throughout the 20th century parallel paths developed small wind plants suitable for farms or residences, and larger utility-scale wind generators that were connected to electricity grids for remote use of power.

History of Wind Power The first wind mill appeared in Europe in 12th century they generated pumps and electrocity. Then later in 19th century, In Denmark there were about 2,500 windmills by 1900, used for mechanical loads such as pumps and mills, producing an estimated combined peak power of about 30 MW. In the American midwest between 1850 and 1900, a large number of small windmills, perhaps six million, were installed on farms to operate irrigation pumps.[8] Firms such as Star, Eclipse, Fairbanks-Morse and Aeromotor became famed suppliers in North and South America.

The first windmill was used for the production of electricity was built in Scotland by Prof. James Blyth. The wind turbine was installed in the garden of his holiday cottage to power the lighting in the cottage. The Brush wind turbine had a rotor 56 feet (17 m) in diameter and was mounted on a 60 foot (18 m) tower. Although large by today's standards, the machine was only rated at 12 kW; it turned relatively slowly since it had 144 blades. Blyth first offered the surplus of electricity, but other people, unfamiliar with such invention considered it “the work of the devil.” The machine was abandoned in 1908 when electricity became more available. So after the development in electricity, the windmill became more familiar in farms, and individuals started having their own windmill to light their homes. And from 1970s and onward, because of the oil price increased rapidly, people started looking for an alternative non-petroleum energy source, which many of them figured, wind power.

Now... Now, the price of coal is relatively cheap, but now the cost is not a problem. The rising concerns is over energy security, global warming and fossil fuel depletion. Now people are starting to be aware of other resources of energy, which led to an expansion of interest in all available forms of renewable energy. Wind power is one. The fledging commercial wind power industry began expanding at a growth rate of about 30% every year, driven by large wind resources and falling cost and prices due to development in technology and improved wind farm management. In the past years, oil crisis caused many petroleum users to shift to coal or natural gas. However, such solution started having its own problems, whether environmental problems or supply problems, that renewable energy is the big issue today. Wind power is certainly one and is still being investigated further to make it more efficient.

Energy transformation Solar energy heating Earth Kinetic energy of air kinetic energy of turbine Electrical energy

Wind Generator Basic features of a horizontal axis wind turbine: a) Tower to support rotating blades. b) Blades that can be rotated to face into the wind. c) Generator. d) Storage system or connection to a distribution grid. Wind Generator

How does wind generator work? Wind power is simple. When wind blows, the wind rotates the turbines of the power plant, creating a lift to make the rotor to turn. The gears start to run in high speed, working on the generator, creating electricity. Because there is no heating or cooling within the process of generating electricity, wind energy source need no materials that are needed to create heat. Therefore no CO2 gases are released into atomosphere. Plus, with no heating or cooling procedure, no steam is released into atmosphere creating no clouds which also trap heat as water is one of the greenhouse gases.

Efficiency of Wind Power

Power by wind generator

Limitation of wind power formula Wind power formula is an estimate because... a) Not all KE of wind is transformed into mechanical energy b) Wind speed varies over course of year c) Density of air varies with temperature d) Wind not always directed at 900 to blades

Sample problems A wind turbine has a rotor diameter of 20 m and the speed of the wind is 25 m/s on a day when the air density is 1.3 kg/m3. Calculate the power that could be produced if the turbine is 30% efficient.

Answer A wind turbine has a rotor diameter of 20 m and the speed of the wind is 25 m/s on a day when the air density is 1.3 kg/m3. Calculate the power that could be produced if the turbine is 30% efficient.

Maximum amount of power It is impossible to extract this maximum amount of power from the air because of ... a) Speed of air... b) Frictional losses... a) Speed of air cannot drop to zero after impact with blades b) Frictional losses in generator and turbulence around blades

Advantages of Wind Power 1. Renewable source of energy 2. Source of energy is free 3. No global warming effect – no CO2 emissions 4. No harmful waste products

Disadvantages of Wind Power 1. Large land area needed to collect energy since many turbines are needed 2. Unreliable since output depends on wind speed 3. Site is noisy and may be considered unsightly 4. Expensive to construct

ONE QUESTION...

Why are turbines not placed near one another? a) Less KE available for next turbine b) Turbulence reduces efficiency of next turbine

Future of Wind Power Globally 38,025 MW of capacity were added in 2009, bringing the total to 159,213 MW, a 31% increase. The graph shows the top 10 producers (with the exceptions of Denmark and Portugal) and includes Japan (which is 13th). Wind power is now generating 2% of global electricity demand, according to the World Wind Energy Association. The countries with the highest shares of wind energygenerated electricity: Denmark 20%, Portugal 15%, Spain 14%, Germany 9%. Wind power employed 550,000 people in 2009 and is expected to employ 1,000,000 by 2012. From 2005 to 2009 the global installed wind power capacity increased 170% from 59,033 megawatts to 159,213 megawatts. The percent of global capacity of the 9 countries in the graph has stayed remarkably consistent: from 81% in 2005 growing slowly to 83% in 2009. Over the 4 year period the capacity in the USA increased 284% and in China increased 1,954%. China grew 113% in 2009, the 4th year in a row it more than doubled capacity. In 2007, Europe had for 61% of installed capacity and the USA 18%. At the end of 2009 Europe had 48% of installed capacity, Asia 25% and North America 24%. Also, when looked at the other diagram, there is a predicted graph. It is predicted that the capacity of wind power plant will grow, showing that the demand of such renewable power is growing as the concerns of other forms of electricity grows. In the future, it is widely predicted that the capacity will grow every year. Now since many disasters occured due to other energy sources such as fukushima accident in Japan, in which the nuclear power plant leaked radioactive waste into the atomosphere, more and more people are being attracted to much cleaner and safer way of generating electricity.

Is wind power the solution? However, is wind power the solution? With growing population, more and more land are being occupied. So less lands are being avaliable to construct wind turbines. Plus, because of the cost and being reluctant on luck for the wind to blow to generate electricity, wind power plants is sometimes considered unconditionable, therefore unfavorable. But, becuase of its efficiency and creating no harmful wastes, wind power is considered a possible solution. Whether wind power is a best solution of energy created by natural resources is still in debate.

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