Wind Energy

Wind Energy

Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the anomaly 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. This wind flow, or motion energy, when "harvested" by windturbines, can be used to generate electricity.

Societies have taken advantage of wind power for thousands of years. The first known use was in 5000 BC when people used yacht to sail the Nile River. Persians had already been using windmills for 400 years by 900 AD in order to pump water and grind grain. Windmills may have even been developed in China before 1 AD, but the earliest written documentation comes from 1219. Cretans were using "literally hundreds of sail-rotor windmills to pump water for crops and livestock."

Wind Energy Sources

Today, people are realizing that wind power "is one of the most promising new energy sources" that can act as an alternative to fossil fuel-generated electricity.

With today's technology, wind energy could provide 20% of America's electricity (or about the amount nuclear power provides) with turbines installed on less than 1% of its land area. And within that area, less than 5% of the land would be occupied by wind equipment the remaining 95% could continue to be used for farming or ranching. By the year 2020, 10 million average American homes may be supplied by wind power, preventing 100 million metric tons of CO2 emissions every year. Lessening our dependence on fossil fuels is critical to the health of all living things, and wind energy can do just that.

The 3 billion kWh of electricity produced by America's wind machines annually displace the energy equivalent of 6.4 million barrels of oil and avoid 1.67 million tons of carbon emissions, as well as sulfur and nitrogen oxide emissions that cause smog and acid rain. In other words, "more wind power means less smog, acid rain, and greenhouse gas emissions."

Windmills may have been around for almost 1500 years, but it was not imagined that wind power would become affordable enough to compete with fossil fuels. Indeed it has. In fact, many utility services around the world offer wind-generated electricity at a premium of 2 to 3 cents per kWh. If a household used wind power for 25% of its needs, it would spend only $4 or $5 dollars per month for it and the price is still dropping.

Compare this to 4.8 to 5.5 cents per kWh for coal or 11.1 to 14.5 cents per kWh for nuclear power. Wind energy is therefore "cheaper than any other new electric generation except natural gas.[which] emits one pound of greenhouse gases for every kilowatt-hour of electricity it generates." The success of this energy is in part due to the fact that its costs have gone "down by more than 80% since the early 1980s." Even lower prices are expected, as "industry analysts see the cost dropping by an additional 20 percent to 40 percent by 2005."

Wind Turbines

Wind turbines, like aircraft propeller blades, turn in the moving air and power an electric generator that supplies an electric current. Simply stated, a wind turbine is 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.

To ensure windturbines that are big in size work in a better manner, a new kind of air-flow technology may soon be introduced. Apart from other aspects, it will focus on efficiency of blades used in the wind turbines. The technology will help in increasing the efficiency of these turbines under various wind conditions. This is a significant development in the area of renewable energy after new wind-turbine power generation capacity got added to new coal-fired power generation in 2008.

Advantages and Disadvantages of Wind-Generated Electricity

A Renewable Non-Polluting Resource

Wind energy is a free, renewable resource, so no matter how much is used today, there will still be the same supply in the future. Wind energy is also a source of clean, non-polluting, electricity. Unlike conventional power plants, wind plants give out no air pollutants or greenhouse gases. According to 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 15 million pounds of other pollutants that would have otherwise been produced. It would take a forest of 90 million to 175 million trees to provide the same air quality.

Cost Issues

Even though the cost of wind power has decreased dramatically in the past 10 years, the technology requires a higher initial investment than fossil-fueled generators. Roughly 80% of the cost is the machinery, with the balance being site preparation and installation. If wind generating systems are compared with fossil-fueled systems on a "life-cycle" cost basis (counting fuel and operating expenses for the life of the generator), however, wind costs are much more competitive with other generating technologies because there is no fuel to purchase and minimal operating expenses.

Environmental Concerns

Although wind power plants have relatively little impact on the environment compared to fossil fuel power plants, there is some concern over the noise produced by the rotor blades, aesthetic (visual) impacts, and birds and bats having been killed (avian/bat mortality) by flying into the rotors. Most of these problems have been resolved or greatly reduced through technological development or by properly wind plants.

Supply and Transport Issues

The major challenge to using wind as a source of power is that it is intermittent and does not always blow when electricity is needed. Wind cannot be stored (although wind-generated electricity can be stored, if batteries are used), and not all winds can be harnessed to meet the timing of electricity demands. Further, good wind sites are often located in remote locations far from areas of electric power demand (such as cities). Finally, wind resource development may compete with other uses for the land, and those alternative uses may be more highly valued than electricity generation. However, wind turbines can be located on land that is also used for grazing or even farming.

Refer

(1): http://witscience.org/study-summation-effects-wind-turbines-earths-rotation/

(2) http://en.wikipedia.org/wiki/Wind_power 

(3) http://www.darvill.clara.net/altenerg/wind.htm