What Is Wind Energy Explanation For Kids?
What is Wind?
Wind is simply air in motion. It is caused by the uneven heating of the Earth’s surface by the sun. Some areas of the Earth receive direct radiation from the sun all year and are usually quite warm. Other places receive indirect radiation, so the climate is cooler. Warm air rises, and cooler air rushes in to take its place, causing winds to blow (weatherwizkids.com).
The greater the temperature difference between two areas, the faster the wind blows between them. Land areas heat and cool more quickly than large bodies of water. During the day, the air over 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 over water rushes in to take its place, creating wind. At night, the winds reverse direction as the air cools more rapidly over land than over water (kids.britannica.com).
Winds are generated because of air pressure differences across the planet. This air pressure difference is due to uneven heating of the Earth’s surface from the Sun. Warm air rises while cool air sinks, causing this difference in pressure. Wind flows from areas of high pressure to areas of low pressure, trying to equalize the pressure. The greater the difference in pressure, the faster the wind flows.
What Makes the Wind Blow?
The wind blows because the sun heats up different parts of the Earth’s surface unevenly. The Earth’s land and water absorb and lose heat at different rates. For example, land areas like deserts heat up more quickly during the day than oceans. The air over the hot deserts also heats up and expands. Colder, denser air over the oceans then rushes in to take its place, creating wind. This heating and rising of lighter, warmer air, along with the movement of heavier, cooler air is what makes the wind blow.
The rotation of the Earth also affects wind patterns. In the Northern Hemisphere, winds are deflected to the right. In the Southern Hemisphere, they are deflected to the left. This is known as the Coriolis effect. It causes the winds to blow in large circular patterns called convection cells which move air around the Earth.
The differences in temperature between the equator and the North and South poles also create winds. Hot air at the equator rises and travels toward the poles. At the same time, cold air from the poles travels toward the equator. This interaction creates more wind patterns around the planet.
Mountains and bodies of water can also channel winds and impact wind patterns and speed. The wind flows faster through narrow spaces like canyons. The wind also blows faster over smooth surfaces like oceans.
So in summary, the main reasons the wind blows are:
- Uneven heating of the Earth’s surface
- The rotation of the Earth (Coriolis effect)
- Temperature differences between the equator and poles
- The impacts of landforms like mountains and bodies of water
Wind Energy
Wind energy is the process of using the wind to generate electricity. Wind turbines convert the kinetic energy in wind into mechanical power. This mechanical power turns a generator to produce electricity (Source: https://www.eia.gov/kids/energy-sources/wind/).
Wind turbines are usually grouped together into wind farms. Many of these wind farms are being built both on land and offshore at sea. When the wind blows, the turbine’s blades spin around. This spinning motion turns a shaft inside the turbine, which goes into a gearbox. The gearbox increases the rotational speed to the right amount needed by the generator. The generator uses magnetic fields to convert the rotational energy into electrical energy. The electricity is then sent through transmission and distribution lines to homes, businesses, schools, and other users (Source: https://kids.earth.org/climate-change/what-is-wind-energy/).
Wind energy is considered a renewable energy source because the wind will blow as long as the sun shines. Harnessing wind power doesn’t produce any emissions or toxic pollution. Wind turbines can also be built on existing farms or ranches so the land can remain in use for agriculture. Overall, using wind to produce energy has fewer negative effects on the environment compared to many other energy sources.
Wind Turbines
Wind turbines convert wind energy into electricity using the aerodynamic force from the rotor blades. The wind blows and pushes the blades around a rotor, which spins a shaft connected to a generator to produce electricity. The most common type of wind turbine has three blades and sits atop a tall tower.
The main components of a wind turbine are:
- Tower – Tall towers support the rotor high up where wind speeds are greater. Most utility-scale turbines have towers 80-100 meters tall.
- Blades – Most turbines have three aerodynamic blades that catch the wind. Longer blades can capture more wind energy.
- Rotor – The blades and hub together form the rotor, which spins when hit by wind.
- Nacelle – The nacelle sits atop the tower and contains the gearbox, generator, brakes, and control systems.
- Generator – Wind causes the rotor to spin, which turns a shaft connected to a generator to produce electricity.
The generator sends the electricity down wires inside the tower to a transformer next to the base of the turbine, which converts it to higher voltage levels for transmission and distribution.
For more details on how wind turbines work, check out these informative sources:
[How Do Wind Turbines Work? | Department of Energy](https://www.energy.gov/eere/wind/how-do-wind-turbines-work)
[How does a wind turbine work? | National Grid Group](https://www.nationalgrid.com/stories/energy-explained/how-does-wind-turbine-work)
How Much Wind is Needed?
Wind turbines require a certain amount of wind speed to be able to generate electricity efficiently and economically. According to PBS, some of the newer wind turbines can operate at wind speeds as low as 5 mph (8 km/h). However, most wind turbines require minimum wind speeds between 8-13 mph (12-20 km/h) to start generating electricity.
Once the turbines start spinning and generating power, higher wind speeds allow them to produce more electricity. Most utility-scale wind turbines reach their maximum power output at wind speeds around 30 mph (50 km/h). Extremely high winds around 55 mph (90 km/h) may require turbines to shut down to avoid damage.
So in summary, modern wind turbines can operate with wind speeds between 5-55 mph (8-90 km/h), with optimal generation between 30-50 mph (50-80 km/h). The range makes wind power viable across many geographic locations.
Sources:
https://www.pbsnc.org/blogs/science/how-much-wind-does-a-wind-turbine-need/
http://www.hydroquebec.com/learning/eolienne/
Advantages of Wind Power
Wind power offers several key advantages that make it an attractive renewable energy source.
First, wind is a renewable resource that will never run out. Unlike fossil fuels which are finite, the wind is continuously replenished through natural processes and will be available as long as the sun shines and the earth rotates (EIA). There is an abundant supply of wind energy that can be harnessed.
Second, wind power is a clean energy source that does not produce air pollution or greenhouse gases. Generating electricity from wind emits zero carbon emissions. This makes wind energy better for the environment compared to fossil fuels like coal or natural gas (Funkidslive).
Third, wind turbines can be built on land or offshore in windy locations. This allows wind farms to be sited in places ideal for capturing wind energy. With smart siting and grid planning, wind power can be harnessed at large scales to meet electricity demands (EIA).
Disadvantages of Wind Power
While wind energy has many benefits, it also comes with some drawbacks. Here are some of the main disadvantages of wind power:
Intermittent power generation – The wind does not blow constantly, which means wind turbines do not produce electricity all the time. The energy produced depends on the wind speed, which can vary greatly from moment to moment and day to day. This makes wind power an intermittent energy source.
Expensive – The initial capital costs of constructing large-scale wind farms and purchasing and installing the turbines are quite high. The infrastructure required such as roads and transmission lines also adds to the costs. According to Constellation, the overall costs can range from $48,000 to $65,000 per installed MW capacity.1
Noise and visual impacts – Some people find the swishing or whooshing sound from turbine blades disturbing if they live close to a wind farm. The visual impact of turbines on the landscape can also be seen as an eyesore by local communities.
Fun Facts About Wind
Here are some fun facts about wind that kids will find fascinating!
The windiest place on Earth is Commonwealth Bay in Antarctica. It experiences winds over 200 mph! That’s faster than most race cars!
Wind power provides over 6% of the world’s electricity. That’s enough to power over 150 million homes!
Wind turbines come in all shapes and sizes. The largest has blades longer than a football field!
Birds and planes can safely fly near wind turbines. The blades spin slow enough that they’re easy to avoid.
Wind often blows faster at higher altitudes. The world’s highest wind turbine sits on a mountain at 13,000 feet.
Kites were the first devices used to capture wind power over 3,000 years ago in China.
The windiest city in the world is Wellington, New Zealand. Residents there tie their garbage cans down to keep them from blowing away!
Sailing ships could not move without wind power. Sails were used for centuries before engines were invented.
Wind power is one of the oldest energy sources we use. It pumps water and grinds grain all over the world.
Types of Wind Turbines
There are two main types of wind turbines: horizontal-axis turbines and vertical-axis turbines. Horizontal-axis turbines are what most people picture when they think of wind turbines. The turbine blades spin on a horizontal axis and the blades look like airplane propellers. Horizontal-axis turbines can have one, two, or three blades. These turbines need to face into the wind to work efficiently.
Vertical-axis turbines spin on a vertical axis instead. The most common type looks like an eggbeater with two or more blades that spin around a vertical pole. Vertical-axis turbines don’t need to face the wind to work, so they can take wind from any direction.
The Future of Wind Power
As technology improves, wind power is expected to play an even bigger role in the future. Here are some key developments to look out for:
Offshore wind farms are being built further out at sea, where wind speeds are faster and more consistent. Floating wind turbines that can be deployed in deep waters are also being developed. According to the U.S. Department of Energy, the technical potential for offshore wind in the United States is over 2,000 gigawatts, nearly double the nation’s current electricity use. [1]
Larger and more efficient wind turbines are being produced. Turbines with higher hub heights can capture faster winds and generate more electricity. Advanced blade designs and control systems also maximize power production. According to Siemens Gamesa, the power capacity of wind turbines has increased 94-fold since 1980. [2]
Better integration with energy storage systems can enable wind farms to provide more reliable and consistent power. Excess energy can be stored in batteries for use when the wind is low. Hybrid systems that combine wind, solar PV, and storage are gaining interest as well.
