FAQs

The Earth is surrounded by the atmosphere, which is made up of air. Air is a mixture of gas, solid and liquid particles. Energy from the sun heats up the atmosphere and the Earth unevenly.

Cold air contains more air particles than warm air. Cold air is therefore heavier and sinks down through the atmosphere, creating high pressure areas. Warm air rises through the atmosphere, creating low pressure areas. The air tries to balance out the low and high pressure areas – air particles move from areas of high pressure (cold air) to areas of low pressure (warm air). This movement of air is known as the wind.

The wind is also influenced by the movement of the earth. As it turns on its axis the air does not travel directly from areas of higher pressure to areas of lower pressure. Instead, the air is pushed to the west in the northern hemisphere and to the east in the southern hemisphere. This is known as the Coriolis force. Click to see a diagram of how the movement of the Earth affects wind.

The Earth’s surface is marked with trees, buildings, lakes, sea, hills and valleys, all of which also influence the wind’s direction and speed. For example, where warm land and cool sea meet, the difference in temperature creates thermal effects, which causes local sea breezes.

Wind is usually measured by its speed and direction. Wind atlases show the distribution of wind speeds on a broad scale, giving a graphical representation of mean wind speed (for a specified height) across an area. They are compiled by local meteorological station measurements or other wind-related recorded data.

Traditionally, wind speed is measured by anemometers – usually three cups that capture the wind rotating around a vertical axis (pictured below). The wind direction is measured with weather vanes.

After measuring wind data for at least one year, the mean annual wind speed can be calculated. Wind speed and wind direction statistics are visualised in a wind rose, showing the statistical repartition of wind speed per direction.

Wind statistics show the best sites to locate wind farms according to the best wind resources. They also provide further information on how the turbines should be positioned in relation to each other and what the distance between the turbines should be.

A wind turbine is a machine that transforms the kinetic energy of the wind into mechanical or electrical energy. Wind turbines consist of a foundation, a tower, a nacelle and a rotor. The foundation prevents the turbine from falling over. The tower holds up the rotor and a nacelle (or box).

The nacelle contains large primary components such as the main axle, gearbox, generator, transformer and control system. The rotor is made of the blades and the hub, which holds them in position as they turn. Most commercial wind turbines have three rotor blades. The length of the blades can be more than 60 metres.

Click here to see how a wind turbine works!

The average size of onshore turbines being manufactured today is around 2.5-3 MW. One 2.5 MW onshore turbine produces power for over 1,500 average EU households.

The largest onshore turbine is a 7 MW turbine with a rotor diameter of 127 m.

Offshore turbines currently reach just over to 6 MW with a rotor diameter of 120 metres – longer than a football field and powering around 5,500 average EU households.

The towers are mostly tubular and made of steel or concrete. The blades are made of fibreglass reinforced polyester or wood-epoxy. They are light grey because it is inconspicuous under most lighting conditions. The finish is matt, to reduce reflected light.

There are many factors at play when designing a wind farm. Ideally, the area should be as wide and open as possible in the prevailing wind direction, with few obstacles. Its visual influence needs to be considered – few, larger turbines are usually better than many smaller ones.

The turbines need to be easily accessible for maintenance and repair work when needed. Noise levels can be calculated so the farm is compatible with the levels of sound stipulated in national legislation. The turbine supplier defines the minimum turbine spacing, taking into account the effect one turbine can have on others nearby – the ‘wake effect’.

Then, the right type of turbine must be chosen. This depends on the wind conditions and landscape features of the location, local/national rules such as on turbine height, noise levels and nature conservation, the risk of extreme events such as earthquakes, how easy it is to transport the turbines to the site and the local availability of cranes.

Construction time is usually very short – a 10 MW wind farm can easily be built in two months. A larger 50 MW wind farm can be built in six months.

Costs vary but the major cost is the turbine itself. This is a capital cost that has to be paid up front and typically accounts for 75% of the costs. Once it is up and running there are few costs – and of course no fuel and carbon costs.

The total cost per KW of installed wind power worldwide varies from €750 euros to more than €2,000 in high cost countries, such as Japan.
For more information on costs specifically in Europe, see EWEA’s electricity cost calculator.

At the end of 2012 there were 225,000 turbines spinning inin 79 countries worldwide.
As technology progresses, turbines are becoming bigger and more efficient. The same amount of energy can be generated with fewer machines.

There is currently 21.7 MW of wind power capacity installed per 1,000 km of land area in the EU, with the highest densities in Denmark and Germany.

Onshore wind turbines are usually decommissioned after generating electricity for 20-25 years. Offshore, the life-span is usually longer, 30 years or more.

Wind turbines start operating at wind speeds of 4 to 5 metres per second and reach maximum power output at around 15 metres/second. At very high wind speeds, i.e. gale force winds, (25 metres/second) wind turbines shut down. A modern wind turbine produces electricity 70-85% of the time, but it generates different outputs depending on the wind speed.

Over the course of a year, it will typically generate about 30% of the theoretical maximum output (higher offshore). This is known as its capacity factor. The capacity factor of conventional power stations is on average 50%. Because of stoppages for maintenance or breakdowns, no power plant generates power for 100% of the time.

The blades rotate between 15-20 revolutions per minute at constant speed. However, an increasing number of machines operate at variable speed, where the rotor speed increases and decreases according to the wind speed.

Wind turbines produce no greenhouse gas emissions during their operation. It takes a turbine just three to six months to produce the amount of energy that goes into its manufacturing, installation, operation, maintenance and decommissioning after its 20-25 year lifetime. During its lifetime a wind turbine delivers up to 80 times more energy than is used in its production, maintenance and scrapping. Wind energy has the lowest ‘lifecycle emissions’ of nearly all energy production technologies.

Wind energy emits no toxic substances such as mercury and air pollutants like smog-creating nitrogen oxides, acid rain-forming sulphur dioxide and particulate deposits. These pollutants can trigger cancer, heart disease, asthma and other respiratory diseases, can acidify terrestrial and aquatic ecosystems, and corrode buildings.

Wind energy creates no waste or water pollution. Given the fact that water scarcity is pressing and will be exacerbated by climate change and population growth, wind energy is key to preserving water resources. Unlike fossil fuel and nuclear power plants, wind energy has one of the lowest water consumption footprints. This is evident in two of the largest wind power markets, USA and China.

In the USA, under the 20 percent Wind Scenario wind power would reduce the annual water consumption in the electric sector by 17 percent by 2030.

In China, the government aims to increase wind power generation capacity to 200 GW by 2020. If achieved, this could save 800 million cubic meters (m3) of water –equivalent to meeting the water demand of 11.2 million households.

Each year we release millions of tonnes of carbon dioxide by burning fossil fuels (oil, coal and gas).

In 2011, the average amount of CO2 emitted by citizens of industrialized countries was around 10 tonnes. This is more than enough CO2 to fill ten three-story buildings in the EU. Certain places around the world have varying averages. According to World Bank data, North America has an average closer to 18 tonnes of CO2 per capita. India however emits 1.5 tonnes per capita, and subsaharian Africa emits only 0.1 tonnes.

Under the 20 percent Wind Scenario, a cumulative total of 7,600 million metric tons of CO2 emissions would be avoided by 2030, and more than 15,000 million metric tons of CO2 emissions would be avoided through 2050 in the USA.

Also, with the Chinese government’s current wind energy goals a 23 percent reduction in carbon intensity could be made by 2020.

In the EU, every kWh of wind energy that is used will save approximately 696g of CO2. EWEA estimates that wind energy avoided the emission of 140 million tonnes of CO2 in 2011 in the EU, equivalent to taking 33% of cars in the EU – 71 million vehicles – off the road. This avoided CO2 costs of around €3.5 billion (assuming a price of €25/t CO2).

Globally, in 2011 wind energy avoided the emission of 350 million tonnes of CO₂. GWEC estimates that this would avoid CO₂ costs of around 35 €billion assuming a price of €10/t CO.

You can find many more global wind numbers and figures in the GWEC’s Global Fact Sheet.

Choosing how your electricity is produced plays an important role in protecting the climate: it’s easy to switch to a green power provider; you request the change and your current and future providers will organise it themselves.

Big environmental and nature conservation groups like Birdlife, WWF, Greenpeace, Friends of the Earth, and Birdlife support wind energy. Birdlife recently stated that climate change was the single largest threat to birds and wind and renewables were a clear solution to climate change.

Wind farms are always subject to an Environmental Impact Assessment to ensure that their potential effect on the immediate surroundings, including fauna and flora, are carefully considered before construction is allowed to start. Deaths from birds flying into wind turbines represent only a tiny fraction of those caused by other human-related sources such as vehicles and buildings.

A 2012 study carried out in the UK (Pearce- Higgins et al.) concluded that a large majority of species can co-exist or thrive with wind farms once they are operating (Journal of Applied Ecology).

According to the Greening Blue Energy study, “Including both on and offshore facilities, estimated rates of mortality for different bird species range from 0.01 to 23 mortalities per turbine per year” (Drewitt & Langston, 2005). It has been estimated that wind turbines in the US cause the direct deaths of only 0.01-0.02% of all of the birds killed annually by collisions with man-made structures and activities.

Wind power can even have local positive effects on biodiversity, and offers an opportunity to practice ecological restoration both onshore and offshore, such as creation of new vegetation and animal habitats, improved fish stocks and other marine life. A two-year study (2011) at the Dutch offshore wind farm Egmond aan Zee revealed that marine life can benefit from the presence of offshore wind turbines, with a higher biodiversity of organisms recorded.

Wind farms are popular with farmers, since their land can continue to be used for growing crops or grazing livestock. Sheep, cows and horses are not disturbed by wind turbines. While the construction of an offshore farm can result in habitat displacement or direct loss of habitat (temporary or permanent), an offshore farm can also protect fish from large scale commercial fishing activities and provide new marine reserves.

Want to learn more about wind power and the environment? If you’re an EWEA member you can check out our Environmental Impact Information Tool!

Beauty is in the eye of the beholder, and whether you think a wind turbine is attractive or not will always be your personal opinion. A 2011 Eurobarometer survey found that 89% of EU citizens are in favour of wind energy, compared to 43% for coal and just 36% for nuclear. 84% think wind energy will have a positive effect on our future way of life.

Awareness campaigns such as the Global Wind Day help inform people around the world about the benefits of wind energy.

The noise of wind turbines has been reduced significantly. Improved design has drastically reduced the noise of mechanical components so that the most audible sound is that of the wind interacting with the rotor blades. This is similar to a light swishing sound, and much quieter than other types of modern-day equipment. Even in generally quiet rural areas, the sound of the blowing wind is often louder than the turbines.
A 2010 Canadian report, ‘The Potential Health Impact of Wind Turbines’, confirmed that noise level emissions complied with the World Health Organisation (WHO) recommendations for residential areas.

Wind energy is one of the cleanest, most environmentally-friendly energy sources. It emits no greenhouse gases or air pollutants. It emits no particles, unlike fossil fuels which are carcinogenic and severely affect human health.

A study, Wind Turbine Sound and Health Effects, was conducted in 2009 by a panel of medical professionals from the US, Canada, Denmark, and UK. The study concluded, “There is no evidence that the audible or sub-audible sounds [including infrasound] emitted by wind turbines have any direct adverse physiological effects.”

A new study published by the Bavarian Environment Agency in Germany in 2012 has concluded similarly to the previous. The study – ‘Wind turbines: does infrasound affect health?’ concludes that wind turbines do not generate infrasound at a level that would damage human health. Wind energy structures generate infrasound that is far below normal human hearing and perception; this is why it does not cause any damage to people. 

Yes! Nearly 45 GW of new wind power, put online in 2012, represents investments of about $56 billion. Additionally, according to the latest UNEP report on the green economy, in 2011 approximately 700,000 people were employed directly or indirectly in the global wind power industry.

The EU accounted for 37.5 percent of the global market in 2012. The top five global markets are in US, China, Germany, Spain and India. In fact, today most of the major growth markets are outside of the OEDC.

Brazil is leading the way in Latin America, followed by Mexico. Chile, Uruguay, Costa Rica, Honduras and Argentina are just some in the region whom are also beginning to choose wind power as a way to meet the needs of a growing economy while increasing their energy independence. Latin American and Caribbean region reached 3,505 MW of installed wind power in 2012

Sub-Saharan Africa, Ethiopia, Tanzania, Kenya and South Africa are also now building a plant, joining Egypt, Morocco and Tunisia in leading wind power development in the African continent. Total installed wind power capacity in Africa and Middle East in 2012 – 1,135 MW

Wind energy makes people less dependent on fuel imports at unpredictable prices. In 2011, wind power production worldwide avoided fuel costs of €35 bn assuming a price of €10/t CO2.

Wind-generated power comes at a zero fuel cost and zero CO2 cost, unlike most traditional energy sources. Wind power can also lower electricity prices and bring more competition to the market.

The EU wind energy sector is a net exporter – of €5.7 bn worth of products and services in 2010.

Find out how wind energy affects electricity market prices.

Find out for yourself using EWEA’s electricity cost calculator, which includes the risk of changing fuel and carbon prices.

The calculator shows that in 2010, onshore wind cost €64.9 per Megawatt hour (MWh): less than coal at €67.6. By 2020 the gap should be even wider – €80.3 for coal and €57.41 for wind.

Nuclear is considerably more expensive than wind energy. ‘In liberalised energy markets, building nuclear power plants is no longer a commercially feasible option: they are simply too expensive”, wrote The Economist in March 2012.

Because the fuel for wind power production does not have a cost, the cost can be predicted with great certainty, unlike the fluctuations in the price of oil, gas and coal. The increase in the oil price over the past few years from $20 to over $100 has added $45 billion to the EU’s annual gas import bill.

The more wind power produced, the less reliant it is on fossil fuels at unpredictable prices.

 

Yes, onshore wind power is competitive once all the costs that affect traditional energy sources – like fuel and CO2 costs, and the effects on environment and health – are factored in.

Taking CO2 costs alone – if a cost of €10 per tonne of CO2 emitted was applied to power produced, onshore wind energy would be the cheapest source of new power generation in Europe.

EU turbine manufacturers had a global market share of 27.4 percent in 2010, consisting of 89 percent of the EU market, 32 percent of the US market, and 8 percent of the Chinese market (the world’s largest market).[1] Of the 10 largest wind turbine manufacturers in the world, four are EU-based. Five of the 10 largest wind energy developers in the world are EU-based. European companies, despite numerous protectionist policies outside the EU, have achieved a higher share in foreign markets than non-European manufacturers have achieved in Europe.



[1] MAKE Consulting 2011

Electricity from renewable energy sources is supported by EU governments in different ways, known as “support mechanisms’”. The most common support mechanism for electricity from renewable energy sources is the feed-in tariff (green electricity quotas in combination with tradable green certificates are also used in countries such as Belgium, Sweden, and Romania).

Under a feed-in tariff, electricity utilities must buy renewable electricity at a price that reflects what it cost to generate it. Under this system, the renewable electricity is dispatched in priority to the grid and producers generally sign long-term contracts (12-25 years) for the energy produced. These instruments allow renewables to be developed, and investors to get a reasonable return on renewable energy investments.

From 2010, feed-in tariffs were in place in Austria, Cyprus, the Czech Republic, Estonia, Finland, France, Germany, Hungary, Ireland, Latvia, Lithuania, Luxembourg, the Netherlands, Portugal, Slovakia and Switzerland.

Certain countries (Denmark, Spain) use a feed-in premium. This is where green electricity producers get the market price plus a fixed premium. This system, which exposes green electricity producers to market dynamics, is well adapted to countries with a large penetration of wind power. Germany gives green electricity producers the possibility to choose between a feed-in tariff and a feed-in premium.

Although electricity produced by wind is supported by governments, oil, gas, coal and nuclear all receive subsidies, and, despite having been subsidised for more than 50 years, continue to get substantially more than wind.

The International Energy Agency’s 2011 World Energy Outlook shows that in 2010, renewables got just $1 for every $6-7 given by governments to fossil fuels.

Using the Fossil Fuel Subsidies data documented in the OECDs 2011 report “Inventory of estimated budgetary support and tax expenditures for fossil fuels”  we can see that fossil fuels are receiving seven times the level of subsidies of renewable energy.

The IEA goes forecasts that government support for renewables will increase to $250 billion in 2035. That is still – a quarter of a century in the future – less than two-thirds of the sum being doled out to fossil fuels today. The UK has now set aside £54bn for decommissioning its nuclear power stations – enough to pay for wind turbines to produce 40 percent of UK’s power demand

According to the European Council in 2011, the EU imports 54 percent of its energy and this is set to increase to 70 percent by 2030. Europe is dependent on countries such as Russia, Algeria and Colombia for oil, gas and coal. In 2010 each person in the EU paid €706 to countries like Russia, Algeria and Colombia to import oil, gas and coal.

Using an indigenous source of energy such as the wind helps the EU be more self-reliant, providing its own power. In 2010 avoided fuel costs from wind power production was €5.71 bn.

In 2011, approximately 670,000 people were employed directly or indirectly in the global wind power industry. According to an Energy [R]evolution 2012 report, wind energy would employ 1.7 million people by 2030.

Jobs range from manufacturing to services and development. There is currently a shortage of skilled workers and engineers in the wind business.

By 2020, more than 520,000 people will be employed by wind energy. By 2030, the figure will be 794,079, with 62 percent of wind jobs in the offshore sector.

The ability to generate electricity is measured in watts. Watts are very small units, so the terms kilowatt (kW = 1,000 watts), megawatt (MW = 1 million watts), and gigawatt (GW = 1 billion watts) are most commonly used to describe the capacity of generating units like wind turbines or other power plants.

Electricity production and consumption are most commonly measured in kilowatt hours (kWh). A kilowatt-hour means one kilowatt (1,000 watts) of electricity produced or consumed for one hour. One 50 watt light bulb left on for 20 hours consumes one kilowatt-hour of electricity (50 watts x 20 hours = 1,000 watt-hours = 1 kilowatt-hour).

The output of a wind turbine depends on the turbine’s size and the wind’s speed through the rotor. Wind turbines manufactured today have power ratings ranging from 250 watts to 7 MW.

An onshore wind turbine with a capacity of 2.5–3 MW can produce more than 6 million kWh in a year – enough to supply 1,500 average EU households with electricity.

Wind power currently supplies about 3.5 percent of global electricity supply. Industry projections show that wind power will, with the right policy support, double in capacity by 2015 and again by the end of this decade. This will deliver somewhere between 8 and 12 percent of global electricity supply.

Wind provides 28.3 percent of electricity in Denmark and also makes a double digit contribution of 16 percent  in  Portugal and Spain. It contributes more than 40 percent of annual electricity in three German states and 20 percent of South Australia’s electricity

The wind passes over the blades creating lift (like an aircraft wing) which causes the rotor to turn. The blades turn a low-speed shaft inside the nacelle: gears connect the low speed shaft of the rotor with a high speed shaft that drives a generator. Here, the slow rotation speed of the blades is increased to the high speed of generator revolution. Some wind turbines do not contain a gearbox and instead use a direct drive mechanism to produce power from the generator.

The rapidly spinning shaft drives the generator to produce electric energy. Electricity from the generator goes to a transformer which converts it to the right voltage for the electricity grid. The electricity is then transmitted via the electricity network.

See how a wind turbine works with EWEA’s interactive infographic!

The power grid operator constantly matches the electricity generation available to electricity demand. No power plant is 100 percent reliable, and the electricity grid is designed to cope with power plants shutting down unexpectedly, and times when the wind is not blowing. Wind is variable, but predictable. Wind farm sites are chosen after careful analysis of wind patterns. This enables a forecast of output to be made – information which can be made available to the network operators who will distribute the electricity.

Much of today’s electricity grid was built 40-60 years ago. It was built around large fossil-fuel burning power stations usually sited near large urban areas. European grids are largely national grids.

In order to harness the power of renewable energy, including wind, the grid has to be extended to where the resource is located: i.e. where the wind blows most frequently, and where the sun shines the brightest. For wind, this includes out to sea, and in some remoter land areas. The grid needs to be expanded so that it can deliver power from where the wind is blowing to where it is needed.

The grid also needs to be better interconnected to improve security of supply and prevent black outs – regardless of the source of energy – and in order to improve competition in the electricity market, which would bring down prices. A European grid might also use more modern cables that lose less electricity in transit.

The investment need for new and refurbished grid infrastructure is about €140 bn up to 2020, according to the European Commission. The opportunity is there to make a more modern system that meets tomorrow’s energy, social, environmental and economic needs.

Grid infrastructure upgrade is needed in different parts of the world. Conditions and upgrade needs vary considerably between different countries and regions. Mongolian massive wind resources have initiated a grand vision of an East-Asian super grid.

The idea is to bring Mongolia’s huge renewable energy potential to markets in Japan, via both China and Russia. Mongolia’s more than 1,000 GW of wind potential, combined with solar resources, would be fed through both the Chinese and Russian grids across the South China Sea and Sea of Japan to both Korea and Japan. This is seen as the beginning phase of what will eventually link power systems as far away as India to the west and Indonesia to the south, creating a massive power pool upon which the sun would rarely set.

The Earth is surrounded by the atmosphere, which is made up of air. Air is a mixture of gas, solid and liquid particles. Energy from the sun heats up the atmosphere and the Earth unevenly.

Cold air contains more air particles than warm air. Cold air is therefore heavier and sinks down through the atmosphere, creating high pressure areas. Warm air rises through the atmosphere, creating low pressure areas. The air tries to balance out the low and high pressure areas – air particles move from areas of high pressure (cold air) to areas of low pressure (warm air). This movement of air is known as the wind.

The wind is also influenced by the movement of the earth. As it turns on its axis the air does not travel directly from areas of higher pressure to areas of lower pressure. Instead, the air is pushed to the west in the northern hemisphere and to the east in the southern hemisphere. This is known as the Coriolis force. Click to see a diagram of how the movement of the Earth affects wind.   The Earth’s surface is marked with trees, buildings, lakes, sea, hills and valleys, all of which also influence the wind’s direction and speed. For example, where warm land and cool sea meet, the difference in temperature creates thermal effects, which causes local sea breezes.

 

 

The above FAQs are Global ones (download GWEC’s Global Fact Sheet). If you are looking for FAQs for Europe, please have a look EWEA’s FAQs!