What is Wind Energy?- Definition, Pros, and Cons

What is Wind Energy?

Wind power or wind energy describes the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or can be converted into electricity by a generator.

Wind power is a popular sustainable, renewable energy source that has a much smaller environmental impact compared to burning fossil fuels.

The wind is an intermittent source of energy that cannot be dispatched when needed. Locally, there is a variable performance that is constant from year to year but changes significantly over shorter periods of time. Therefore, it must be used in conjunction with other power sources to ensure a reliable supply.

Wind Energy Basics

The wind is caused by the uneven heating of the atmosphere by the sun, fluctuations in the earth’s surface, and the earth’s rotation. Mountains, bodies of water, and vegetation influence wind flow patterns.

Wind turbines convert the energy in the wind into electricity by rotating propeller-like blades around a rotor. The rotor turns the driveshaft, which turns an electric generator.

Three key factors affect the amount of energy a turbine can harness from the wind:

  • Wind speed,
  • Air density, and
  • Swept area.

The equation for Wind Power

P = {1\over2} \rho A V^3

Wind speed

The amount of energy in the wind varies with the cube of the wind speed. In other words, when the wind speed doubles, there is eight times more energy in the wind (23 =2x2x2=8). Small changes in wind speed have a major impact on the power available in the wind.

The density of the air

The denser the air, the more energy the turbine receives. The air density varies with altitude and temperature. Air is less dense at higher altitudes than at sea level, and warm air is less dense than cold air. If everything else is the same, turbines will produce more power at lower altitudes and in places with cooler average temperatures.

The swept area of the turbine

The larger the swept area (the size of the area through which the rotor spins), the more power the turbine can capture from the wind. Since the swept area is A = pir2, where r = radius of the rotor, a small increase in blade length results in a larger increase in the power available to the turbine

wind energy

Things You Didn’t Know About Wind Power

  1. Human civilizations have used wind power for thousands of years. Early forms of a windmill used the wind to crush grain or pump water. Today, modern wind turbines use the wind to generate electricity. Learn how a wind turbine works.
  2. Today’s wind turbines are much more complicated machines than the traditional prairie windmill. A wind turbine consists of up to 8,000 different components.
  3. Wind turbines are Big. Wind turbine blades average over 190 feet long and turbine towers average 295 feet high – about the height of the Statue of Liberty.
  4. Higher wind speeds mean more electricity and wind turbines get taller to reach higher heights above the ground where it is even windier. Use the Department of Energy’s Wind Resource Maps to find the average wind speeds in your state or hometown. For more information on taller wind turbine opportunities, see a report from the Department of Energy’s National Renewable Energy Laboratory.
  5. Most of the components of wind turbines installed in the United States are manufactured here. There are more than 500 wind-related manufacturing facilities located across 43 states, and the U.S. wind industry currently employs more than 114,000 people.
  6. Offshore wind represents a major opportunity to provide power to highly populated coastal cities, and the nation’s first offshore wind farm was installed off the coast of Rhode Island in 2016. See what the Energy Department is doing to develop offshore wind in the United States.
  7. With North Carolina’s first utility-scale wind farm coming online in early 2017, there is now utility-scale wind power installed in 41 states. There is distributed wind installed in all 50 states plus Puerto Rico, Guam, and the U.S. Virgin Islands.
  8. The United States’ wind power capacity was 105.591 megawatts at the end of 2019, making it the largest renewable energy source in the United States. That’s enough electricity to offset the consumption of 29.5 million average American homes.
  9. Wind energy is affordable. Wind prices for power contracts signed in the last few years and levelized wind prices (the price the utility pays to buy power from a wind farm) are 2–4 cents per kilowatt-hour.
  10. Wind energy provides more than 10% of total electricity generation in 14 states, and more than 30% in Kansas, Iowa, and Oklahoma.

Advantages of Wind Energy

Harnessing the wind to generate energy has its advantages and is an efficient option for many different parts of the world since it doesn’t depend on direct sunlight exposure like solar energy.

1. Wind Energy Is Clean and Renewable

Unlike coal, natural gas, or oil, generating electricity from wind doesn’t result in greenhouse gas emissions. While there are some environmental considerations that come with building large wind farms, once operational, wind turbines themselves don’t require burning any fossil fuels to operate.

Additionally, wind energy is completely renewable and will never run out. In opposition to traditional fossil fuel resources that replenish very slowly, wind naturally occurs in our atmosphere, and we don’t have to worry about supply issues in the future.

2. Free Fuel

Since wind turbines themselves run strictly on the power of wind-generated, there is no need for fuel. Once the turbine is complete and installed, it doesn’t need to be fueled or connected to power to continue working.

This also reduces the overall cost to continue to run large-scale wind farms in comparison to other forms of renewable energies, which require may require some energy investment.

3. Wind Energy Has Low Operating Costs

As far as upfront costs go, wind farms or individual turbines can be expensive to install. However, once up and running, operating costs are relatively low; their fuel (wind) is free, and the turbines don’t require too much maintenance over the course of their lifetime.

4. Wind Energy Is Space-Efficient

Cumulatively, wind farms can take up a lot of land space; however, the actual turbines and equipment don’t use up a lot of real estates. This means that land used for wind turbines can often also be used for other purposes, such as farming

5. Advances in Technology

The latest advances in technology have transformed preliminary wind turbine designs into extremely efficient energy harvesters. Turbines are available in a wide range of sizes, increasing the market to many different type’s businesses and individuals for use at home on larger lots and plots of land.

As technology improves, so do the functionalities of the structure itself, creating designs that will generate even more electricity, require less maintenance, and run more quietly and safely.

Disadvantages of wind energy

Although wind energy is a renewable, greener option of energy, it still has its disadvantages and limitations.

1. Wind energy is intermittent

A wind turbine’s effectiveness in generating electricity depends on the weather; thus, it can be difficult to predict exactly how much electricity a wind turbine will generate over time. If wind speeds are too low on any given day, the turbine’s rotor won’t spin.

This means wind energy isn’t always available for dispatch in times of peak electricity demand. In order to use wind energy exclusively, wind turbines need to be paired with some sort of energy storage technology.

2. Wind energy causes noise and visual pollution

One of the biggest downsides of wind energy is noise and visual pollution. Wind turbines can be noisy when operating, as a result of both the mechanical operation and the wind vortex that’s created when the blades are rotating.

Additionally, because wind turbines need to be built up high enough to capture a good amount of wind, the turbines can often interrupt otherwise scenic landscapes, such as mountain ranges, lakes, oceans, and more.

3. Wind plants can impact local wildlife.

A wind turbine’s blades are very large and rotate at very high speeds. Unfortunately, their blades can harm and kill species that fly into them, like birds and bats. The construction of wind farms can also disrupt the natural habitats of local species if not conducted in a sustainable manner.

However, these problems can be solved to some extent with technological advancements and properly-siting wind farms.

4. Looks

Wind turbines need to be built high in order to capture enough wind, which makes them a prominent part of any landscape. Some people find that large wind turbines are an eyesore, however, this is more of a personal preference.

5. Location limitations

In order for wind turbines to be economically viable, they need to be installed in a place where they will produce enough electricity. Wind farms are best suited for coastal areas, the tops of hills, and open planes – essentially anywhere with strong, reliable wind.

Most of these suitable places tend to be in remote areas far outside of cities and towns, in more rural areas, or offshore. Because of this distance, new infrastructure, such as power lines, has to be built in order to connect a wind farm to the power grid.

This can be costly and may cause some harm to the surrounding environment (i.e by tearing down trees to make way for power lines).

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