What is Wind Energy?
Wind energy is a form of solar energy. Wind energy (or wind power) is defined as a process by which wind is used to generate electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. A generator can convert mechanical power into electricity.
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 the 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
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.
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.
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
Things You Didn’t Know About Wind Power
- 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 wind to generate electricity. Learn how a wind turbine works.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- Wind energy provides more than 10% of total electricity generation in 14 states, and more than 30% in Kansas, Iowa, and Oklahoma.
Pros and Cons of Wind Energy
Wind energy offers many advantages, which explains why it is one of the fastest-growing energy sources in the world. The research efforts aim to address the challenges of making greater use of wind energy. Read on to learn more about the benefits of wind energy and some of the challenges it is working to address.
Advantages of Wind Power
- Wind power is cost-effective. The Land-based utility-scale wind is one of the most affordable energy sources available today. It costs 1–2 cents per kilowatt-hour after the tax credit for production. Because wind farm electricity is sold at a fixed price over a long period of time (e.g. 20 years) and its fuel is free, wind energy reduces the price uncertainty that fuel costs add to traditional energy sources.
- Wind creates jobs. The US wind sector employs more than 100,000 people, and the wind turbine technician is one of the fastest-growing American jobs. According to the Wind Vision Report, Wind has the potential to support more than 600,000 manufacturing, installation, maintenance, and support jobs by 2050.
- Wind enables U.S. industry growth and U.S. competitiveness. New wind projects account for over $10 billion in annual investment in the US economy. The United States has tremendous domestic resources and a highly skilled workforce and can compete in the global clean energy economy.
- It’s a clean fuel source. Wind energy doesn’t pollute the air like power plants that rely on burning fossil fuels like coal or natural gas, which emit particulate matter, nitrogen oxides, and sulfur dioxide, causing problems for human health and economic damage. Wind turbines do not cause atmospheric emissions that cause acid rain, smog, or greenhouse gases.
- The Wind is a domestic source of energy. The nation’s wind supply is plentiful and inexhaustible. Wind power capacity in the US has grown by 15% per year over the past 10 years, and wind power is the largest renewable energy source in the US today.
- It’s sustainable. The wind is actually a form of solar energy. Winds are caused by the warming of the atmosphere by the sun, the rotation of the earth, and the irregularities of the earth’s surface. As long as the sun is shining and the wind is blowing, the energy generated can be used to send electricity via the grid.
- Wind turbines can be built on existing farms or ranches. This greatly benefits the economy in rural areas, where most of the best wind locations can be found. Farmers and ranchers can continue to work the land as the wind turbines only use a fraction of the land. Wind turbine owners make rent payments to the farmer or ranchers for the use of the land in order to provide the landowners with additional income.
Challenges Of Wind Power
- Wind power must still compete with conventional generation sources on a cost basis. Although the cost of wind power has dropped dramatically in the past few decades, wind projects must be able to compete economically with the cheapest source of electricity, and some locations may not be windy enough to be competitive.
- Good land-based wind sites are often located in remote locations, far from cities where electricity is needed. Transmission lines need to be built to bring the electricity from the wind farm to the city. However, building a few transmission lines that have already been proposed could significantly reduce the cost of expanding wind energy.
- Wind resource development might not be the most profitable use of the land. Land suitable for wind-turbine installation must compete with alternative uses for the land, which might be more highly valued than electricity generation.
- Turbines might cause noise and aesthetic pollution. Although wind turbines have relatively little environmental impact compared to traditional power plants, there are concerns about the noise generated by the turbine blades and the visual impact it has on the landscape.
- Wind plants can impact local wildlife. Birds were killed by flying into spinning turbine blades. Most of these problems have been solved or greatly reduced through technology development or the proper installation of wind turbines. Bats have also been killed by turbine blades, and research is underway to develop and improve solutions to reduce the impact of wind turbines on these species. Like all energy sources, wind projects can alter the habitat on which they are built, which can alter the suitability of that habitat for certain species.
Wind energy is a form of solar energy. Wind energy (or wind power) describes the process by which wind is used to generate electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. A generator can convert mechanical power into electricity.
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.
Advantages of Wind Power:
1. Wind power is cost-effective.
2. Wind creates jobs.
3. Wind enables U.S. industry growth and U.S. competitiveness.
4. It’s a clean fuel source.
5. The wind is a domestic source of energy.
6. It’s sustainable.
7. Wind turbines can be built on existing farms or ranches.