Wind+energy!

Wind is just air in motion. It is caused by the uneven heating of the Earth's surface by the sun. Because the Earth's surface is made of very different types of land and water, it absorbs the sun's heat at different rates. One example of this uneven heating can be found in the daily wind cycle. Wind is a clean, renewable resource that is good for the environment. Wind machines, called turbines, create energy without burning fuel, so it makes for a pollution-free alternative to oil. Turbines are used today mostly to generate electricity.

Energy from Moving Air
Wind is simply air in motion. It is caused by the uneven heating of the Earth's surface by the sun. Because the Earth's surface is made of very different types of land and water, it absorbs the sun's heat at different rates. One example of this uneven heating can be found in the daily wind cycle.

The Daily Wind Cycle
During the day, the air above the land heats up more quickly than the air over water. The warm air over the land expands and rises, and the heavier, cooler air rushes in to take its place, creating wind. At night, the winds are reversed because the air cools more rapidly over land than over water. In the same way, the atmospheric winds that circle the earth are created because the land near the Earth's equator is heated more by the sun than the land near the North and South Poles. Wind: A Clean Fuel Wind Farm In the 1970s, oil shortages pushed the development of alternative energy sources. In the 1990s, the push came from a renewed concern for the environment in response to scientific studies indicating potential changes to the global climate if the use of fossil fuels continues to increase. Wind energy is an economical power resource in many areas of the country. Wind is a clean fuel; wind power plants (also called wind farms) produce no air or water pollution because no fuel is burned to generate electricity. Growing concern about emissions from fossil fuel generation, increased government support, and higher costs for fossil fuels (especially natural gas and coal) have helped wind power capacity in the United States grow substantially over the past 10 years.

The first modern wind turbine was built in Vermont in the early 1940s. Wind farms currently produce enough electricity to meet the needs of more than 600,000 families in the United States. The largest wind turbine in the world, located in Hawaii, stands 20 stories tall and has blades the length of a football field. An average wind speed of 14 miles per hour is needed to convert wind energy into electricity. || || One wind turbine can produce enough electricity to power up to 300 homes.
 * In 200 B.C., people in China and the Middle East used windmills to pump water and grind grain.

What are the advantages of wind turbines?

They are pollution free.

The energy they generate is renewable. This means that as long as the winds blow there is power to turn the blades of the rotor.

Using wind energy means that less fossil fuel (coal and oil) needs to be burned to make electricity. Burning fossil fuel pollutes the atmosphere and adds greenhouse gases to it. This type of pollution is a cause of global warming.

What are the disadvantages of wind turbines?

Some people don't like the look of the turbines. They say that they spoil the look of the natural environment.

Wind turbines make noise.

Turbines kill birds that fly into them. However collisions are rare and there are reports from Denmark saying that some falcons had built nests on the top of turbine towers. To protect birds however, it is important that wind farms be built away from bird sanctuaries and from the pathways of migratory birds. (//Migratory birds are those that fly from cold places in winter to warmer parts of the world//)