Onshore+wind

Onshore Wind Power
Onshore wind is a wind from the sea that develops over land near coast lines. Onshore wind is formed the difference in temperature between the sea and land. The sea has a greater specific heat than land; therefore, the sea can absorb heat more than land. Because of that, the sea surface needs more time to be warmed up than land’s surface. When the sun heats land surface and makes its temperature rise, the air above will be heated as well. As the warm air is less dense, it rises up and then reduces the pressure. At that time, the cooler air above the sea which is with higher pressure flow toward the land into the lower pressure. 
 * 1.Onshore wind: **

Wind energy has been used for a long time. Humans have used wind to move sailboats or balloon. In addition, wind energy has been also used to produce mechanical energy through the windmill. The idea of ​​using wind energy to produce electricity was formed right after the invention of electricity and generators. The principle of windmill has been changed a bit in order to convert wind power into electricity instead of mechanical energy. Windmills used for generating electricity are commonly known as wind turbine.
 * 2.Electricity generation: **
 * [[image:how_wind_turbine_works.jpg width="503" height="298"]] || How do wind turbines make electricity? Simply stated, a wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. ||

Currently, there are two different types of wind turbines: Horizontal axis turbine and vertical axis turbine.
 * 3.Type of wind turbine:**


 * Description || [[image:HAWT_copy.jpg width="205" height="330" align="center"]]


 * Horizontal-axis wind turbines (HAWT) have the main rotor shaft and electrical generator at the top of a tower, and must be pointed into the wind. || [[image:VWAT_copy.jpg width="205" height="330" align="center"]]


 * Vertical-axis wind turbines (VAWT) have the main rotor shaft arranged vetically. The turbine does not need to be pointed into the wind to be effective. ||
 * || * Small turbines are pointed by a simple wind vane, while large turbines generally use a wind sensor coupled with a servo motor.
 * In term of producing electricity, horizontal axis wind turbine is more efficient that vertical one. HAWT is usually used of wind farm. || * Suitable where the wind direction is highly variable, for example when integrated into buildings.
 * With a vertical axis, the generator and gearbox can be placed near the ground, hence avoiding the need of a tower and improving accessibility for maintenance.
 * Wind speeds are very low close to ground level, so although you may save a tower, your wind speeds will be very low on the lower part of your rotor.
 * The overall efficiency of the vertical axis machines is not impressive.
 * The disadvantage of the vertical turbines are they may require guide ropes to hold the shaft in place ||

A wind farm is a group of wind turbines in the same location used for production of electric power. Individual turbines are interconnected with a medium voltage (usually 34.5 kV) power collection system and communications network. At a substation, this medium-voltage electrical current is increased in voltage with a transformer for connection to the high voltage transmission system. <span style="font-family: 'Arial','sans-serif';">A large wind farm may consist of several hundred individual wind turbines, and cover an extended area of hundreds of square miles, but the land between the turbines may be used for agricultural or other purposes.
 * <span style="font-family: 'Arial','sans-serif';">4.Wind farm: **

<span style="font-family: 'Arial','sans-serif';">Wind energy is currently one of the cheapest regenerative energy sources. Wind energy costs are estimated to be around 1 400 USD/kW for onshore (1.4 USD per Watt)
 * <span style="font-family: 'Arial','sans-serif';">5.Wind power potential: **

<span style="font-family: 'Arial','sans-serif';">Wind energy has potential to be one of the most suitable alternative resources in the future when fossil fuel become very scarce. · <span style="font-family: 'Arial','sans-serif';">The IWES/BWE study finds that if wind power was developed on all suitable land in Germany – around 2% of the surface area – it could generate f electricity per year. Germany’s current electricity demand stands at 600TWh per year. This shows that wind power’s potential easily outstrips nuclear power’s current electricity generation, which is around 140TWh per year. · <span style="font-family: 'Arial','sans-serif';">In case of Australia, there is a [|calculation] that if all suitable area will be use for producing electricity by onshore wind turbine, about 241TWh will be generated, which is not far from the total electricity demand of Australian in 2006 – 2007 year - 262TWh.
 * <span style="font-family: 'Arial','sans-serif';">6.SWOT Analysis **


 * <span style="font-family: 'Arial','sans-serif';">Strengths: **
 * <span style="font-family: 'Arial','sans-serif';">Wind power is free and unconventional energy source that is renewable and never ending (as long as the sun still exists).
 * <span style="font-family: 'Arial','sans-serif';">Wind energy does not cause pollution, and using wind power instead of using traditional resources such as coal or oil contributes to protect environment.
 * <span style="font-family: 'Arial','sans-serif';">Unlike solar cell which can only generate power in day light, the wind turbine can produce electricity all day.
 * <span style="font-family: 'Arial','sans-serif';">The technology that is involved in harnessing the wind energy is quite simple and straight forward.
 * <span style="font-family: 'Arial','sans-serif';">Wind turbines cost also works in favour of this source of power because the investment incurred on development and operation of these turbines is earned back within 3 months of operation.
 * <span style="font-family: 'Arial','sans-serif';">Decommissioning of wind turbines is also quite easy as compared to that of other power sources.

<span style="font-family: 'Arial','sans-serif';">[] <span style="font-family: 'Arial','sans-serif';">[] <span style="font-family: 'Arial','sans-serif';">http://en.wikipedia.org/wiki/Wind_turbine <span style="font-family: 'Arial','sans-serif';">http://guidedtour.windpower.org/en/tour/design/horver.htm <span style="font-family: 'Arial','sans-serif';">http://ramblingsdc.net/Australia/WindPPotential.html
 * <span style="font-family: 'Arial','sans-serif';">Weaknesses: **
 * <span style="font-family: 'Arial','sans-serif';">The operation of the turbine depends upon the speed and force of the wind. A gloomy force makes the turbine turn slowly and thus produces less power.
 * <span style="font-family: 'Arial','sans-serif';">Wind turbine generates decent power compared with the amount of electricity produced by other methods such as nuclear power plant.
 * <span style="font-family: 'Arial','sans-serif';">Wind turbines are vulnerable to the extremities of the weather. A storm could damage wind turbines (mostly, the blades).
 * <span style="font-family: 'Arial','sans-serif';">Finally, noise created by the blades is one disadvantage of wind turbine.
 * <span style="font-family: 'Arial','sans-serif';">Opportunities: **
 * <span style="font-family: 'Arial','sans-serif';">Wind power industry has created many job opportunities. The wind industry in 1995 employed some 30,000 people worldwide. This estimate is based on a study from the Danish Wind Industry Association, which was published in 1995.
 * <span style="font-family: 'Arial','sans-serif';">In addition, wind industry is a new field of business that has gain lots of profit. In 2006, the export from the Danish wind industry was 5.23 billion USD. In 2006 the Danish manufactures sold 5.439 MW; power roughly corresponding to 33 percentage of the global market.
 * <span style="font-family: 'Arial','sans-serif';">Threats: **
 * <span style="font-family: 'Arial','sans-serif';">The significant threat caused by wind turbine is that the blades of wind turbine can impact some species. There have been some researches pointing out that wind turbine can kill birds and bats.
 * <span style="font-family: 'Arial','sans-serif';">7.Reference: **