Wind energy frequently asked questions (FAQ) | EWEA
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What is the wind?
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Wind refers to the movement of air caused by the uneven heating of the Earth's surface by the sun. This heating creates high and low pressure areas in the atmosphere, prompting air to flow from regions of high pressure to low pressure, resulting in what we commonly refer to as wind.
Air density varies with temperature; cold air is denser and sinks, leading to high pressure, while warm air rises, creating low-pressure areas. Additionally, the Earth's rotation affects wind direction through the Coriolis effect, making winds in the Northern Hemisphere deflect to the west and those in the Southern Hemisphere to the east.
The landscape around us also influences wind patterns. For example, temperature variations between land and sea can lead to local sea breezes.
Category: FAQ topic 1
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How can you measure the wind?
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To measure wind, we typically assess both its speed and direction. Wind atlases illustrate the distribution of wind speeds in various geographical areas, based on data from meteorological stations.
The conventional method for measuring wind speed involves using anemometers, which typically consist of multiple cups rotating around a vertical axis, while weather vanes gauge wind direction.
After compiling wind data over the course of at least a year, the mean annual wind speed can be calculated, providing insights into ideal locations for wind farms.
Category: FAQ topic 1
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What is a wind turbine?
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A wind turbine is a device designed to convert wind's kinetic energy into mechanical or electrical energy. It consists of several key components: a foundation that anchors the structure, a tower that supports the rotor and nacelle, the nacelle housing essential machinery like the gearbox and generator, and the rotor comprised of blades that harness wind energy.
Typically, a commercial wind turbine features three blades, which can each measure up to 60 meters in length.
See how a wind turbine works!
Category: FAQ topic 1
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How big is a wind turbine?
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Currently, onshore wind turbines have an average capacity of 2.5 to 3 MW with blades measuring around 50 meters. This can supply electricity to approximately 1,500 households in the EU.
Meanwhile, an offshore turbine typically has a capacity of about 3.6 MW, providing energy for over 3,312 households.
The size of wind turbines has increased significantly over the past decade, with today's largest turbines reaching capacities of 7.5 MW and blade lengths surpassing 60 meters.
Category: FAQ topic 1
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What is a wind turbine made of?
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Wind turbine towers are commonly constructed from steel or concrete and are generally painted light grey to blend with the environment. The blades are fabricated from materials like fiberglass or reinforced polyester, also designed in light grey to minimize visibility.
Category: FAQ topic 1
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How is a wind farm designed?
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Designing a wind farm involves multiple considerations, such as selecting a location clear of obstacles and ensuring easy access for maintenance. The distance between turbines is crucial to minimize interference from the 'wake effect' caused by one turbine impacting another's performance.
The selection of turbine types is based on the site's wind conditions and local regulations regarding height and preservation of the landscape.
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How long does it take to build a wind farm?
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Typically, the construction of a wind farm proceeds quickly; a 10 MW facility can be established in two months, while a larger 50 MW project might require about six months.
Category: FAQ topic 1
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What are the costs of building a wind farm?
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Costs for wind farms can vary, but the primary expenses are linked to the turbines themselves, representing roughly 75% of overall costs. Once operational, wind turbines incur minimal operational and maintenance expenses compared to fossil fuel-based plants.
Category: FAQ topic 1
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How efficient are wind turbines?
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Modern wind turbines are efficient, becoming operational at wind speeds of 4 to 5 m/s and achieving peak output around 15 m/s. Typically, they run at capacity 70-85% of the time, with annual production averaging about 24% of their maximum potential output.
Category: FAQ topic 1
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Why do some wind turbines have two and others three blades?
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The choice between two or three blades comes down to the turbine's intended function. Turbines designed for electricity generation typically require fewer blades for higher speeds, thus most modern systems favor three blades for optimal efficiency. However, two-blade designs can be lighter and less expensive.
Category: FAQ topic 1
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Why do some of the turbines in a wind farm sometimes stand still?
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Turbines may pause for several reasons: regular maintenance, mechanical issues, or adverse wind conditions. In high winds, they are shut down to prevent damage.
Category: FAQ topic 1
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How much space does a wind farm need?
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Wind turbines occupy less than 1% of the land in a wind farm, allowing for continued agricultural activities and wildlife coexistence.
Category: FAQ topic 1
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Could I put a turbine in my garden or on the roof of my house?
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Interest in small-scale wind turbines for home and community use is increasing. Homeowners can learn more about setting up such systems by contacting their national wind energy associations.
Click here to find your national association.
Category: FAQ topic 1
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Who makes wind turbines?
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Interested individuals can review our Members Directory for a comprehensive list of wind turbine manufacturers.
Category: FAQ topic 1
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Why don't we put all wind turbines out to sea?
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Currently, onshore wind energy remains more cost-effective than offshore projects due to the challenging conditions at sea. Offshore wind farms require more time to develop, which could delay the fulfilment of renewable energy goals.
However, as technology improves and offshore costs decrease, the potential of offshore wind energy is becoming increasingly attractive.
Category: FAQ topic 1
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How many wind turbines are there in the EU?
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As of 2020, the EU boasted 70,488 onshore and 1,132 offshore wind turbines. Over time, wind turbine technology has progressed, making them larger and more efficient.
Currently, there is a total wind power capacity of 19.5 MW installed per 1,000 km² of land in the EU, with Denmark and Germany leading the way.
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How long does a wind turbine work for?
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Wind turbines have a lifespan of approximately 20 to 25 years, capable of producing electricity for up to 120,000 hours, significantly longer than the average car engine.
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How fast do the blades turn?
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The rotation speed of turbine blades ranges between 15-20 revolutions per minute, with many modern designs featuring variable speed capabilities to adjust to changing wind conditions.
Category: FAQ topic 1
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Five most frequently asked questions and answers about ...
Last fall, after a ten-year break, the construction of a modern wind farm began again in Estonia. What has changed in wind turbine technology in ten years? How much electricity does one wind turbine produce? Andrus Zavadskis, Technical Manager of Utilitas Wind, answers these and other frequently asked questions about wind turbines.
- What has changed in wind turbine technology in ten years?
Over the past decade, wind turbine technology has seen remarkable advancements. Today's turbines are larger, more powerful, and thus more efficient in electricity production. A larger turbine results in fewer units needed to generate the same power output.
For instance, consider the Paldiski wind farm, where each turbine has a capacity of 2.5 MW, compared to the upcoming Saarde wind farm's 4.3 MW turbines. The latter's nine turbines will yield more energy annually than the eighteen in the former farm.
- Why are wind turbines white in color?
Three primary reasons justify the white coloration of wind turbines: aesthetics, safety, and durability. From the ground, white offers a neutral appearance, while it remains visible from the air, enhancing flight safety for both aircraft and birds. Moreover, the white surface reflects sunlight, reducing equipment heat buildup which can impair turbine life.
- How much electricity does one wind turbine produce?
The electricity generation capacity of a single wind turbine is influenced by factors such as size, capacity, and site conditions. Modern turbines exhibit capacity factors typically between 40% to 50%, increasing past 50% in advantageous locations like offshore sites.
For example, the Saarde wind farm in Pärnu is planned to generate around 135 GWh annually, sufficient for over 40,000 homes in Pärnu County.
- What happens if there is no wind?
While wind turbines' energy production fluctuates based on wind conditions, Estonia has external capacities exceeding its cold season needs. The Nordic and Baltic regions are seldom devoid of wind, and during low wind periods, solar and hydroelectric plants can compensate for energy needs.
- Why do we need wind electricity?
Generating electricity from renewable sources like wind reduces dependence on fossil fuels, crucial for mitigating climate change impacts. With growing electricity demand and the rise of electric vehicles, finding cleaner energy solutions is imperative.
In Estonia, wind energy serves as a viable source due to regional wind patterns. Moreover, wind-generated electricity offers cost savings as there are no fuel expenditures, thereby driving down electricity prices.
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