WIND ENERGY

WIND

Wind is the movement of air across the surface of the Earth, from areas of high pressure to areas of low pressure.

The surface of the Earth is heated unevenly by the Sun, depending on factors such as the angle of incidence of the sun's rays at the surface and whether the land is open or covered with vegetation. Also, large bodies of water, such as the oceans, heat up and cool down slower than the land. The heat energy absorbed at the Earth's surface is transferred to the air directly above it and, as warmer air is less dense than cooler air, it rises above the cool air to form areas of high pressure and thus pressure differentials. These effects combine to cause wind

Shaping the Surface of the Earth.

ENERGY

Wind energy is the kinetic energy of air in motion

Two main designs of wind turbine:

wind energy---mechanical energy---electricity

Vertical tubines: using the wind to spin on a centre point on the ground, resulting in the whole construction spinning round.Horizontal tubines: more common type, using blades to creat friction when facing wind and resulting in spinning motion.

How dose wind turbine work?wind turbine: a device that convert wind energy

tower

blades

nacelle

When wind spins the blades of the turbines. The blades are attached to a hub, which is mounted onto a shaft. The shaft, in turn, connects to the gearbox transmission, which increases the rotational speed of the turbine blades. The gearbox is connected to a high-speed shaft, and this shaft turns the generator, producing electricity.

How dose wind turbine work?wind turbine: a device that convert wind energy

Sizes and Applications

Small (10 kW)• Homes• Farms• Remote Application

Intermediate (10-250 kW)

• Village Power• Hybrid Systems• Distributed Power

Large (660 kW - 2+MW)

• Central Station Wind Farms

• Distributed Power• Community Wind

Wales

•Capacity: 1 MW, completed in 2000

Ponnequin, Colorado

•Turbine Size: 660-750 kW

•Capacity: 31.5 MW

Compare wind energy with other forms of energy

Wind Power is Clean

Compared to nearly every other major type of mass energy production available, wind power is exceptionally clean. Although harnessing wind energy does require wind towers considered unsightly--and, thus, visual pollution--by some, the environmental impact of wind energy is significantly lower than energy types which require combustion such as coal, wood and oil.

Wind Power is Safe

Compared to other "alternative" energy sources such as nuclear, wind energy has an exceptionally high safety rating. Because the harnessing of wind energy does not require combustion of any materials (like that required by coal or oil energy) and does not require dangerous manipulation of materials (like that required by nuclear energy), wind energy is widely considered to be one of the safest energy sources available. Some environmentalists have expressed marginal concern, however, about the safety of birds flying in the vicinity of windmills.

Wind Power is Limitless

Unlike fossil fuels such as coal and oil, wind energy makes use of an ever-changing, renewable and sustainable energy source: the flow of air between high and low pressure systems in Earth's atmosphere. In communities with continuous wind presence, especially coastal and mountain communities, wind energy is a safe, clean form of energy that cannot be depleted. In addition, wind energy can be stored for later use or in times of less wind generation, or the energy can be supplemented with other clean energy sources such as nuclear or hydroelectricity.

Environmental impact of wind power

. Compared to the environmental impact of traditional energy sources, the environmental impact of wind power is relatively minor.ind power consumes no fuel, and emits no air pollution, unlike fossil fuel power sources. The energy consumed to manufacture and transport the materials used to build a wind power plant is equal to the new energy produced by the plant within a few months.

While a wind farm may cover a large area of land, many land uses such as agriculture are compatible, with only small areas of turbine foundations and infrastructure made unavailable for use

Livestock ignore wind turbines,and continue to graze as they did before wind turbines were installed

Environmental impact of wind power

Wind farm near an open-pit coal mine in Germany. Wind farms are often built on or near land that has already been impacted by land clearing.

In the United States, landowners typically receive $3,000 to $5,000 per year in rental income from each wind turbine, while farmers continue to grow crops or graze cattle up to the foot of the turbines.

Summaries and Review

The Steps of Wind

(1) Wind energy

Originated from _______ and ________.

(2) Wind turbine

Consist of three parts:

_________, _________ and _________.

(3) Generator

mechanical energy → electricity

Summaries and Review

The energy conversion in this process

Heat Energy

→Mechanical Energy

↘

Electrical Energy

→

↗

↘

Heat Energy

Mechanical Energy

Light Energy→

↓

→

Summaries and Review

True or False 1) Wind is created by Gods.

2) Wales Colorado has intermediate-sized turbine engines.

3) Wind farms are often built on or near land that has already been impacted by land clearing.

4) Wind energy is a safe, clean form of energy that cannot be depleted.

5) Vertical turbines are more common than horizontal turbines.

6) Wind energy has relatively minor impact on the environment.

Summaries and Review

Fill in the Blanks 1) The power of a small sized turbine will be less than

_______. 2) What are the three major advantages of using wind

energy. ________ , _________ and _________. 3) What amount of money do the landowners in the US

benefit per year by using wind energy? $________. 4) Write down the formula which calculates wind

energy.