Wind Energy Faq's
Does the wind industry depend on government subsidies? 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. “Fossil fuels [are] still receiving four times the level of subsidies [as renewable energy]”, European Commission said in 2011 (in the Communication: “Renewable Energy: Progressing towards the 2020 target”.) 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 half 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. What happens when the wind stops blowing? The power system operator constantly matches the electricity generation available to electricity demand. No power plant is 100 per cent reliable, and wind power is variable but predictable, allowing hours or even days for system operators to compensate for changing wind conditions. The power grid is designed to cope with power plants shutting down unexpectedly; wind energy is often referred to as ‘intermittent’, but ‘variable’ is a much better word. What is ‘intermittent’ is a nuclear power plant which can (and often does) go from 1,000 MW of production to zero in less than one second; that will never happen with wind power.
How big is a wind turbine? The average size of turbines sold into the market in 2011 was 1.67 MW, enough to produce power for up to 1,000 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. How long does it take to build a wind farm? From the inception of the project to commissioning of the plant is usually 2-3 years or longer. However, most of the time is involved with planning, permitting, arranging financing, etc. The actual 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. What are the costs of building a wind farm? 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. How many wind turbines are there in the world? At the end of 2011 there were 199,064 turbines spinning globally. 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. How long does a wind turbine work for? The ‘design’ life of a wind turbine is usually 20 years. Wind power is a relatively new industry, however, so there are actually very few machines that have reached that age yet. Some turbines in Germany and Denmark have been spinning quite happily well past their 20 year design life‌while others have been replaced before the end of their design life because the technology has evolved so rapidly. How fast do the blades turn? 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. What other environmental benefits does wind power bring? 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. Do wind turbines affect human health? Despite some claims to the contrary, an increasing quantity of independent research indicates that wind turbines are not harmful to human health. The wind industry is committed to engagement with experts in science, medicine and occupational and environmental health to monitor on-going credible research in the area of wind turbines and human health. Wind energy is one of the cleanest, most environmentally-friendly energy sources. It emits no greenhouse gases or air pollutants. It emits no particles of any kind, and certainly no particles which are carcinogenic and severely affect human health, as do fossil fuels. In July 2012, Health Canada published the results of a national study on wind turbines, sound and human health; and concluded that wind energy is one of the safest sources of electricity. See a summary of the main conclusions reached in 17 reviews of the research literature on wind farms and health:
The 17 reviews of the research literature on wind farms and health can be viewed here. Is wind power good for the economy? Yes! The 40.5 GW of new wind power, which came online in 2011, represents investments of about $68 billion. Additionally, according to the latest UNEP report on the green economy, in 2011 approximately 670,000 people were employed directly or indirectly in the global wind power industry. The EU accounted for 27.4 percent of the global market in 2010. The top five global markets are in China, US, India, Germany and Spain. In fact, today most of the major growth markets are outside of the OECD. 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.
Ethiopia, Tanzania, Kenya and South Africa are also now in the wind business, joining Egypt, Morocco and Tunisia in leading wind power development in the African continent. Wind energy makes people less dependent on fuel imports at unpredictable prices. In 2010, wind power production in Europe avoided fuel costs of €5.71 bn. 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.
How much electricity can one wind turbine generate? 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. How does a wind turbine produce 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. From there, there are two major variations: a) the shaft is connected to a gearbox which raises the low speed of the rotor shaft to 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 – usually 1500rpm in Europe and most of Asia to produce 50hz; or 1800 rpm in North America to produce 50hz
b) in ‘direct drive’ turbines – the rotor shaft is connected directly to the generator, which is generally much larger and more electrically complex. 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.
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