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Wind power

Is Wind Energy Renewable?

Wind Power in the U.S.

Wind power can be considered today a renewable energy source? or is only another form of non-renewable energy like fossil fuels, which are limited resources and are responsible for the pollution of the atmosphere.

How is Wind Created on Planet Earth?

The wind on planet Earth is produced by the Sun because our star heats the different layers of air in the atmosphere in an uneven way, which makes the warm air layers to rise, and the cold layers of air to move down.

This movement of the different layers of air up and down in the atmosphere is what we call the wind.

The wind does not require the presence of the Sun all the time because the air layers keep moving even during the night, which means that the wind can blow 24 hours a day.

How We Turn the Wind into Electricity?

The wind blows due to the movement of the air layers in our atmosphere, but its speed depends on several factors.

An area covered by many obstacles such as large trees, buildings and landforms like hills and mountains could slow down the speed of the wind.

The wind is stronger in open areas with no obstacles (natural or man-made) such as plains or even in offshore areas because there are no natural obstacles, and the wind blows freely there.

We can turn the wind into clean electricity by using a horizontal or vertical axis wind turbine.

Such a device uses the kinetic power of the wind to spin the blades of the turbine and generate electricity with the help of a generator.

Reading the advantages and disadvantages of wind power will help you to better understand why the power of the wind can help you ditch the dirty fossil fuels.

Is Wind Power Renewable or Non-renewable?

The answer to this question is definitely Yes!

The wind is produced on our planet by the Sun, which is considered a renewable energy source because compared with our time here on Earth is endless, and represents for us a continuous resource of clean energy, heat and light.

Being produced by a renewable energy source (the Sun), the wind itself and the energy produced by wind turbines are both renewable.

Types of Wind Turbines

We are harnessing the power of wind today using wind turbines installed both onshore and offshore.

There are two different types of wind turbines used to generate clean electricity.

1. Horizontal Axis Wind Turbines – HAWT

This is the most common type of wind turbine used both for large scale and residential electricity generation.

There are several sizes of horizontal wind turbines, the larger ones being installed for large scale energy generation both onshore and offshore, while the smaller ones can be installed in the yard or on the roof to generate power at residential scale.

Conventional horizontal wind turbines use three blades, but there are also wind turbines using only two blades.

The kinetic energy of the wind is converted into rotational motion by the blades of the turbine.

Because the turbine rotates at slow speed, this speed is transferred to the gearbox through the main shaft of the turbine.

The gearbox increases the rotational speed up to a level that is required by the generator to produce electricity.

The increased speed is transferred to the generator from the gearbox through a fast rotating shaft.

The electric energy produced by the generator will be used in the gird combined with electricity produced from other sources.

Because the wind doesn’t come from the same direction all the time, a yawn mechanism is used by the turbine that will rotate the blades of the turbine in the direction of the wind.

The yawn mechanism ensures the continuous production of energy of the horizontal axis wind turbine regardless the direction of the wind.

2. Vertical Axis Wind Turbines – VAWT

The actual technology used by the vertical axis wind turbines is less efficient compared to the technology used by the horizontal axis wind turbines, and this could be the reason why we see on land and on the sea, only horizontal axis wind turbines that generate electricity at utility scale.

However, vertical axis wind turbines are better suited for residential use because they are more silent and friendlier with the environment (they don’t kill birds and bats).

Types of vertical axis wind turbines

Savonius Wind Turbine

The Savonius model is the oldest one because it was used by the Persians about 3,500 years ago.

This type of VAWT is the less efficient one because the turbine rotates at slow speeds.

The Savonius uses drag instead of airfoil-shaped blades and therefore cannot rotate faster than the approaching wind speed.

To generate energy that can feed the grid, the Savonius turbine needs to be geared, which increases costs and reduces the overall efficiency of the turbine.

Darrieus Wind Turbine (eggbeater windmill)

The Darrieus model is a fast rotating vertical axis wind turbine that requires a manual push or a more elaborate starter mechanism because is unable to self start.

However, the Darrieus model uses two or three ‘C’ shaped blades that rotate at high speed and low torque to generate electricity.

Giromill Wind Turbine

The Giromill relies on the same principle like the Darrieus model, but instead of the ‘C’ shaped blades, uses two or three straight blades that are attached to the central axis of the turbine.

This type of VAWT can reach high rotating speeds, which ensures a good efficiency of the turbine.

A Giromill with helical blades is another type of vertical axis wind turbine that uses helical blades attached to the vertical axis of the turbine.

The blades look like being wrapped around the axis of the turbine in a DNA-like structure.

This type of VAWT minimizes the pulsating torque of the conventional Darrieus model, which cause the main bearings of the Darrieus design to fail.

There are several other variations of the Darrieus model of the vertical wind turbine (Gorlov, Cycloturbine, etc.), but all these model cannot compete in terms of efficiency with a horizontal axis wind turbine.

However, the technology in the field evolves, so it is possible that in a not so far future we will see big vertical axis wind turbines generating energy at utility scale.

Wind Energy Facts

1. Is a renewable resource

Wind power is considered today a renewable energy source because the wind is generated by the Sun, but at the same time, this type of renewable energy is intermittent.

2. Wind is intertmittent

Wind does not blow with the same speed every day, so a wind power plant using a large of wind turbines will have an intermittent production of electricity.

3. Wind power is usually paired with power produced from fossil fuels

During the day, the grid has peak hours when the demand of electricity in the grid is very high, so the clean electricity produced by the wind power plant will be combined with electricity generated from other sources (fossil fuels) to ensure a continuous supply of electricity into the grid.

4. Is one of the cheapest forms of renewable energy

Wind energy is one of the cheapest forms of energy available today because the average cost of onshore wind energy is between $59/MWh and $38/MWh (at an average wind speed of 8m/sec.).

5. Wind power plants occupy a small are of sea

An onshore wind power plant can be spread over a large surface of land, but even so, much of the land around the turbines remains usable.

6. Onshore wind turbines work well in agricultural areas

This is the reason why wind power stations built in agricultural areas are not disrupting the crop production.

I already mentioned that wind power is an intermittent source of energy because the wind does not blow all the time with the same speed.

7. Natural gas is a common source of power pairing with wind power

To ensure a continuous source of power for the grid, wind energy is combined with energy produced from fossil fuels such as natural gas.

8. A medium-sized wind turbine can generate a lot of power

An average-sized wind turbine (2 MW horizontal axis turbine) can generate enough energy to power about 1,000 U.S. homes.

9. Large horizontal axis wind turbines are quite noisy

Large horizontal axis wind turbines produce quite a loud noise when due to the rotating blades, and this is the reason why they need to be installed in areas that are away of human settlements.

10. Horizontal axis wind turbines can affect wildlife

Large horizontal axis wind turbines are also responsible for killing hundreds of thousands of birds and bats every year (the rotating blades are the ones that are hitting the birds and the bats flying around the turbine).

11. Vertical axis wind turbines are friendlier with wildlife

This could be the reason why scientists are trying to develop the vertical axis wind turbine technology by increasing its efficiency because this technology is known to be friendlier with the wildlife.

12. Wind power does not consume other resources

Generating clean electricity using the kinetic power of the wind does not consume any water (unlike the power station burning fossil fuels which consume a huge amount of fresh water).

13. Wind power grows faster than solar

The fastest-growing electricity production source in the world today is represented by wind power.

14. Landowners get passive income when hosting a wind turbine

Wind energy projects deliver every year, millions of dollars to local landowners and farmers for land lease.
That land is also open for other activities such as farming and crop production (agricultural).

15. More wind power is produced when the speed of the wind increases

The higher the speed of the wind the higher the energy production of the wind turbine, and this could be the reason why year after year we see that taller horizontal axis wind turbines are produced (wind is stronger at higher altitudes).

16. Wind power is cheaper than conventional electricity

A consumer using electricity produced by wind turbines can pay as low as 5 cents/kWh, but a consumer that uses conventional electricity from the grid (produced by various sources, mostly fossil fuels) can pay the regular price of 12 cents/kWh.

Final conclusion

Wind energy is considered a major source of clean electricity for the future because is both renewable and clean.

In order to reduce the level of air, soil and water pollution produced by the use of fossil fuels, we need to increase the generation capacity of wind power.

Wind along with solar and the other sources of clean and renewable energy on the planet will slowly increase their share in the energy mix of every country, and this will reduce the consumption of fossil fuels for a cleaner and healthier planet.

Article written by:

I am a writer and reporter for the clean energy sector, I cover climate change issues, new clean technologies, sustainability and green cars. Danny Ovy

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