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Visit us! Through wind resource assessment it is possible to provide estimates of wind power potential globally, by country or region, or for a specific site. A global assessment of wind power potential is available via the Global Wind Atlas provided by the Technical University of Denmark in partnership with the World Bank.
The total amount of economically extractable power available from the wind is considerably more than present human power use from all sources. He concluded that somewhere between 18 TW and 68 TW could be extracted. Cristina Archer and Mark Z. Of this, "between 72 and TW could be extracted in a practical and cost-competitive manner".
The strength of wind varies, and an average value for a given location does not alone indicate the amount of energy a wind turbine could produce there. To assess prospective wind power sites a probability distribution function is often fit to the observed wind speed data. The Weibull factor is often close to 2 and therefore a Rayleigh distribution can be used as a less accurate, but simpler model.
A wind farm is a group of wind turbines in the same location used for production of electric power. A large wind farm may consist of several hundred individual wind turbines distributed over an extended area, but the land between the turbines may be used for agricultural or other purposes. For example, Gansu Wind Farm , the largest wind farm in the world, has several thousand turbines. A wind farm may also be located offshore. In a wind farm, individual turbines are interconnected with a medium voltage often Induction generators , which were often used for wind power projects in the s and s, require reactive power for excitation , so substations used in wind-power collection systems include substantial capacitor banks for power factor correction.
Different types of wind turbine generators behave differently during transmission grid disturbances, so extensive modelling of the dynamic electromechanical characteristics of a new wind farm is required by transmission system operators to ensure predictable stable behaviour during system faults. In particular, induction generators cannot support the system voltage during faults, unlike steam or hydro turbine-driven synchronous generators.
Induction generators aren't used in current turbines. Instead, most turbines use variable speed generators combined with partial- or full-scale power converter between the turbine generator and the collector system, which generally have more desirable properties for grid interconnection and have Low voltage ride through -capabilities. Transmission systems operators will supply a wind farm developer with a grid code to specify the requirements for interconnection to the transmission grid.
This will include power factor , constancy of frequency and dynamic behaviour of the wind farm turbines during a system fault. Offshore wind power refers to the construction of wind farms in large bodies of water to generate electric power. These installations can utilize the more frequent and powerful winds that are available in these locations and have less aesthetic impact on the landscape than land based projects. However, the construction and the maintenance costs are considerably higher. Siemens and Vestas are the leading turbine suppliers for offshore wind power.
ON are the leading offshore operators. Offshore wind power capacity is expected to reach a total of 75 GW worldwide by , with significant contributions from China and the US. In , 1, turbines at 55 offshore wind farms in 10 European countries produced 18 TWh, enough to power almost five million households. In a wind farm , individual turbines are interconnected with a medium voltage usually At a substation, this medium-voltage electric current is increased in voltage with a transformer for connection to the high voltage electric power transmission system.
A transmission line is required to bring the generated power to often remote markets. For an off-shore station this may require a submarine cable. Construction of a new high-voltage line may be too costly for the wind resource alone, but wind sites may take advantage of lines installed for conventionally fueled generation. One of the biggest current challenges to wind power grid integration in the United States is the necessity of developing new transmission lines to carry power from wind farms, usually in remote lowly populated states in the middle of the country due to availability of wind, to high load locations, usually on the coasts where population density is higher.
The current transmission lines in remote locations were not designed for the transport of large amounts of energy. Multi state power transmission projects are discouraged by states with cheap electric power rates for fear that exporting their cheap power will lead to increased rates. A energy law gave the Energy Department authority to approve transmission projects states refused to act on, but after an attempt to use this authority, the Senate declared the department was being overly aggressive in doing so.
These are important issues that need to be solved, as when the transmission capacity does not meet the generation capacity, wind farms are forced to produce below their full potential or stop running all together, in a process known as curtailment. While this leads to potential renewable generation left untapped, it prevents possible grid overload or risk to reliable service. As of , there are over , wind turbines operating, with a total nameplate capacity of GW worldwide.
World wind generation capacity more than quadrupled between and , doubling about every 3 years. The United States pioneered wind farms and led the world in installed capacity in the s and into the s. In installed capacity in Germany surpassed the United States and led until once again overtaken by the United States in China has been rapidly expanding its wind installations in the late s and passed the United States in to become the world leader. As of , 83 countries around the world were using wind power on a commercial basis.
The amount of energy generated by a wind turbine depends on:
The actual amount of electric power that wind is able to generate is calculated by multiplying the nameplate capacity by the capacity factor , which varies according to equipment and location. The wind power industry set new records in — more than 50 GW of new capacity was installed. This was largely from new construction in China and India. Global Wind Energy Council GWEC figures show that recorded an increase of installed capacity of more than 63 GW, taking the total installed wind energy capacity to Although the wind power industry was affected by the global financial crisis in and , GWEC predicts that the installed capacity of wind power will be In some cases, wind onshore is already the cheapest electric power generation option and costs are continuing to decline.
Since wind speed is not constant, a wind farm's annual energy production is never as much as the sum of the generator nameplate ratings multiplied by the total hours in a year. The ratio of actual productivity in a year to this theoretical maximum is called the capacity factor. Online data is available for some locations, and the capacity factor can be calculated from the yearly output. Unlike fueled generating plants, the capacity factor is affected by several parameters, including the variability of the wind at the site and the size of the generator relative to the turbine's swept area. A small generator would be cheaper and achieve a higher capacity factor but would produce less electric power and thus less profit in high winds.
Conversely, a large generator would cost more but generate little extra power and, depending on the type, may stall out at low wind speed. A study released by the U. Department of Energy noted that the capacity factor of new wind installations was increasing as the technology improves, and projected further improvements for future capacity factors. Wind energy penetration is the fraction of energy produced by wind compared with the total generation. The wind power penetration in world electric power generation in was 3.
There is no generally accepted maximum level of wind penetration. The limit for a particular grid will depend on the existing generating plants, pricing mechanisms, capacity for energy storage , demand management and other factors. An interconnected electric power grid will already include reserve generating and transmission capacity to allow for equipment failures.
This reserve capacity can also serve to compensate for the varying power generation produced by wind stations. Electrical utilities continue to study the effects of large scale penetration of wind generation on system stability and economics. A wind energy penetration figure can be specified for different duration of time, but is often quoted annually.
Seasonal industry might then take advantage of high wind and low usage times such as at night when wind output can exceed normal demand. In Australia, the state of South Australia generates around half of the nation's wind power capacity. Electric power generated from wind power can be highly variable at several different timescales: hourly, daily, or seasonally. Annual variation also exists, but is not as significant.
Wind power prices now lower than the cost of natural gas
Because instantaneous electrical generation and consumption must remain in balance to maintain grid stability, this variability can present substantial challenges to incorporating large amounts of wind power into a grid system. Intermittency and the non- dispatchable nature of wind energy production can raise costs for regulation, incremental operating reserve , and at high penetration levels could require an increase in the already existing energy demand management , load shedding , storage solutions or system interconnection with HVDC cables.
Fluctuations in load and allowance for failure of large fossil-fuel generating units requires operating reserve capacity, which can be increased to compensate for variability of wind generation.
Wind power is variable, and during low wind periods it must be replaced by other power sources. Presently, grid systems with large wind penetration require a small increase in the frequency of usage of natural gas spinning reserve power plants to prevent a loss of electric power in the event that there is no wind. At low wind power penetration, this is less of an issue. GE has installed a prototype wind turbine with onboard battery similar to that of an electric car, equivalent of 1 minute of production.
Despite the small capacity, it is enough to guarantee that power output complies with forecast for 15 minutes, as the battery is used to eliminate the difference rather than provide full output. In certain cases the increased predictability can be used to take wind power penetration from 20 to 30 or 40 per cent. The battery cost can be retrieved by selling burst power on demand and reducing backup needs from gas plants. In Spain, in the early hours of 16 April wind power production reached the highest percentage of electric power production till then, at A International Energy Agency forum presented costs for managing intermittency as a function of wind-energy's share of total capacity for several countries, as shown in the table on the right.
The additional costs, which are modest, can be quantified. The combination of diversifying variable renewables by type and location, forecasting their variation, and integrating them with dispatchable renewables, flexible fueled generators, and demand response can create a power system that has the potential to meet power supply needs reliably. Integrating ever-higher levels of renewables is being successfully demonstrated in the real world:.
In , eight American and three European authorities, writing in the leading electrical engineers' professional journal, didn't find "a credible and firm technical limit to the amount of wind energy that can be accommodated by electric power grids". In fact, not one of more than international studies, nor official studies for the eastern and western U. Solar power tends to be complementary to wind. On seasonal timescales, solar energy peaks in summer, whereas in many areas wind energy is lower in summer and higher in winter.
In the Institute for Solar Energy Supply Technology of the University of Kassel pilot-tested a combined power plant linking solar, wind, biogas and hydrostorage to provide load-following power around the clock and throughout the year, entirely from renewable sources.
Wind power forecasting methods are used, but predictability of any particular wind farm is low for short-term operation. However, studies by Graham Sinden suggest that, in practice, the variations in thousands of wind turbines, spread out over several different sites and wind regimes, are smoothed. As the distance between sites increases, the correlation between wind speeds measured at those sites, decreases. Thus, while the output from a single turbine can vary greatly and rapidly as local wind speeds vary, as more turbines are connected over larger and larger areas the average power output becomes less variable and more predictable.
Wind power hardly ever suffers major technical failures, since failures of individual wind turbines have hardly any effect on overall power, so that the distributed wind power is reliable and predictable,  [ unreliable source? Typically, conventional hydroelectricity complements wind power very well. When the wind is blowing strongly, nearby hydroelectric stations can temporarily hold back their water. When the wind drops they can, provided they have the generation capacity, rapidly increase production to compensate. This gives a very even overall power supply and virtually no loss of energy and uses no more water.
Alternatively, where a suitable head of water is not available, pumped-storage hydroelectricity or other forms of grid energy storage such as compressed air energy storage and thermal energy storage can store energy developed by high-wind periods and release it when needed. The type of storage needed depends on the wind penetration level — low penetration requires daily storage, and high penetration requires both short and long term storage — as long as a month or more.
Stored energy increases the economic value of wind energy since it can be shifted to displace higher cost generation during peak demand periods. The potential revenue from this arbitrage can offset the cost and losses of storage. For example, in the UK, the 1. In particular geographic regions, peak wind speeds may not coincide with peak demand for electrical power.
In the U. A possible future option may be to interconnect widely dispersed geographic areas with an HVDC " super grid ". Germany has an installed capacity of wind and solar that can exceed daily demand, and has been exporting peak power to neighboring countries, with exports which amounted to some Just as the EU requires member countries to maintain 90 days strategic reserves of oil it can be expected that countries will provide electric power storage, instead of expecting to use their neighbors for net metering. The capacity credit of wind is estimated by determining the capacity of conventional plants displaced by wind power, whilst maintaining the same degree of system security.
The energy needed to build a wind farm divided into the total output over its life, Energy Return on Energy Invested , of wind power varies but averages about 20— According to BusinessGreen , wind turbines reached grid parity the point at which the cost of wind power matches traditional sources in some areas of Europe in the mids, and in the US around the same time. Wind power is capital intensive , but has no fuel costs. However, the estimated average cost per unit of electric power must incorporate the cost of construction of the turbine and transmission facilities, borrowed funds, return to investors including cost of risk , estimated annual production, and other components, averaged over the projected useful life of the equipment, which may be in excess of twenty years.
Energy cost estimates are highly dependent on these assumptions so published cost figures can differ substantially. In , wind energy cost a fifth of what it did in the s, and some expected that downward trend to continue as larger multi-megawatt turbines were mass-produced. Equipment makers can also deliver products in the same year that they are ordered instead of waiting up to three years as was the case in previous cycles Thirty-five percent of all new power generation built in the United States since has come from wind, more than new gas and coal plants combined, as power providers are increasingly enticed to wind as a convenient hedge against unpredictable commodity price moves.
A British Wind Energy Association report gives an average generation cost of onshore wind power of around 3. A EU study shows base cost of onshore wind power similar to coal, when subsidies and externalities are disregarded. Wind power has some of the lowest external costs. In February Bloomberg New Energy Finance BNEF reported that the cost of generating electric power from new wind farms is cheaper than new coal or new baseload gas plants. The expense of gas fired plants is partly due to "export market" effects on local prices. Costs of production from coal fired plants built in "the s and s" are cheaper than renewable energy sources because of depreciation.
The cost has reduced as wind turbine technology has improved. There are now longer and lighter wind turbine blades, improvements in turbine performance and increased power generation efficiency. Also, wind project capital and maintenance costs have continued to decline. Prices have fallen to about 4 cents per kilowatt-hour in some cases and utilities have been increasing the amount of wind energy in their portfolio, saying it is their cheapest option. A number of initiatives are working to reduce costs of electric power from offshore wind.
The NREL is expected to achieve advances in wind turbine design, materials and controls to unlock performance improvements and reduce costs. In more aggressive cases, experts estimate cost reduction Up to 40 percent if the research and development and technology programs result in additional efficiency. The wind industry in the United States generates tens of thousands of jobs and billions of dollars of economic activity. Wind energy benefits from subsidies in many jurisdictions, either to increase its attractiveness, or to compensate for subsidies received by other forms of production which have significant negative externalities.
Many American states also provide incentives, such as exemption from property tax, mandated purchases, and additional markets for " green credits ".
Countries such as Canada and Germany also provide incentives for wind turbine construction, such as tax credits or minimum purchase prices for wind generation, with assured grid access sometimes referred to as feed-in tariffs. These feed-in tariffs are typically set well above average electric power prices.
Senator Lamar Alexander and other Republican senators argued that the "wind energy production tax credit should be allowed to expire at the end of "  and it expired 1 January for new installations. Secondary market forces also provide incentives for businesses to use wind-generated power, even if there is a premium price for the electricity.
For example, socially responsible manufacturers pay utility companies a premium that goes to subsidize and build new wind power infrastructure. Companies use wind-generated power, and in return they can claim that they are undertaking strong "green" efforts. In the US the organization Green-e monitors business compliance with these renewable energy credits.
For example, Vestas , a wind turbine manufacturer, whose largest onshore turbine can pump out 4.
World Wind Energy Association
Individuals may purchase these systems to reduce or eliminate their dependence on grid electric power for economic reasons, or to reduce their carbon footprint. Wind turbines have been used for household electric power generation in conjunction with battery storage over many decades in remote areas. Recent examples of small-scale wind power projects in an urban setting can be found in New York City , where, since , a number of building projects have capped their roofs with Gorlov-type helical wind turbines. Although the energy they generate is small compared to the buildings' overall consumption, they help to reinforce the building's 'green' credentials in ways that "showing people your high-tech boiler" cannot, with some of the projects also receiving the direct support of the New York State Energy Research and Development Authority.
Grid-connected domestic wind turbines may use grid energy storage , thus replacing purchased electric power with locally produced power when available. The surplus power produced by domestic microgenerators can, in some jurisdictions, be fed into the network and sold to the utility company, producing a retail credit for the microgenerators' owners to offset their energy costs. Off-grid system users can either adapt to intermittent power or use batteries, photovoltaic or diesel systems to supplement the wind turbine.
Equipment such as parking meters, traffic warning signs, street lighting, or wireless Internet gateways may be powered by a small wind turbine, possibly combined with a photovoltaic system, that charges a small battery replacing the need for a connection to the power grid. A Carbon Trust study into the potential of small-scale wind energy in the UK, published in , found that small wind turbines could provide up to 1. Distributed generation from renewable resources is increasing as a consequence of the increased awareness of climate change. The electronic interfaces required to connect renewable generation units with the utility system can include additional functions, such as the active filtering to enhance the power quality.
The environmental impact of wind power when compared to the environmental impacts of fossil fuels, is relatively minor. Onshore wind farms can have a significant visual impact  and impact on the landscape. Their network of turbines, access roads, transmission lines and substations can result in "energy sprawl".
Habitat loss and habitat fragmentation are the greatest impact of wind farms on wildlife. The scale of the ecological impact may  or may not  be significant, depending on specific circumstances. Prevention and mitigation of wildlife fatalities, and protection of peat bogs ,  affect the siting and operation of wind turbines.
Wind turbines generate some noise. The United States Air Force and Navy have expressed concern that siting large wind turbines near bases "will negatively impact radar to the point that air traffic controllers will lose the location of aircraft. Before , many wind turbine blades had been made of fiberglass with designs that only provided a service lifetime of 10 to 20 years.
Because they were designed to be hollow took up enormous volume compared to their mass. Landfill operators have started requiring operators to crush the blades before they can be landfilled. Nuclear power and fossil fuels are subsidized by many governments , and wind power and other forms of renewable energy are also often subsidized. For example, a study by the Environmental Law Institute  assessed the size and structure of U. It has been suggested that a subsidy shift would help to level the playing field and support growing energy sectors, namely solar power , wind power, and biofuels.
According to the International Energy Agency IEA , energy subsidies artificially lower the price of energy paid by consumers, raise the price received by producers or lower the cost of production.
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Subsidies to renewables and low-carbon energy technologies can bring long-term economic and environmental benefits". The IEA's report disagreed with claims that renewable energy technologies are only viable through costly subsidies and not able to produce energy reliably to meet demand. However, IEA's views are not universally accepted. Between and , subsidies for wind were between 1.
Subsidies for coal, natural gas and nuclear are all between 0. On a per-kWh basis, wind is subsidized 50 times as much as traditional sources. Following the Japanese nuclear accidents , Germany's federal government is working on a new plan for increasing energy efficiency and renewable energy commercialization , with a particular focus on offshore wind farms. Under the plan, large wind turbines will be erected far away from the coastlines, where the wind blows more consistently than it does on land, and where the enormous turbines won't bother the inhabitants.
The plan aims to decrease Germany's dependence on energy derived from coal and nuclear power plants. Surveys of public attitudes across Europe and in many other countries show strong public support for wind power. Bakker et al. Although wind power is a popular form of energy generation, the construction of wind farms is not universally welcomed, often for aesthetic reasons.
In Spain , with some exceptions, there has been little opposition to the installation of inland wind parks. However, the projects to build offshore parks have been more controversial. In a survey conducted by Angus Reid Strategies in October , 89 per cent of respondents said that using renewable energy sources like wind or solar power was positive for Canada , because these sources were better for the environment. Only 4 per cent considered using renewable sources as negative since they can be unreliable and expensive.
By contrast, 3 out of 4 Canadians opposed nuclear power developments. A survey of residents living around Scotland 's 10 existing wind farms found high levels of community acceptance and strong support for wind power, with much support from those who lived closest to the wind farms. The results of this survey support those of an earlier Scottish Executive survey 'Public attitudes to the Environment in Scotland ', which found that the Scottish public would prefer the majority of their electric power to come from renewables, and which rated wind power as the cleanest source of renewable energy.
The increase is significant as there were twice as many wind farms in as there were in In other cases there is direct community ownership of wind farm projects. The hundreds of thousands of people who have become involved in Germany's small and medium-sized wind farms demonstrate such support there. A Harris Poll reflects the strong support for wind power in Germany, other European countries, and the United States.
In China , Shen et al. In addition, the study finds that like their counterparts in OECD countries, urban Chinese respondents are sensitive to direct costs and to wildlife externalities. Distributing relevant information about turbines to the public may alleviate resistance. Many wind power companies work with local communities to reduce environmental and other concerns associated with particular wind farms.
Appropriate government consultation, planning and approval procedures also help to minimize environmental risks. In America, wind projects are reported to boost local tax bases, helping to pay for schools, roads and hospitals. Wind projects also revitalize the economy of rural communities by providing steady income to farmers and other landowners.
In the UK, both the National Trust and the Campaign to Protect Rural England have expressed concerns about the effects on the rural landscape caused by inappropriately sited wind turbines and wind farms. Some wind farms have become tourist attractions. It is run by the Glasgow Science Centre. In Denmark, a loss-of-value scheme gives people the right to claim compensation for loss of value of their property if it is caused by proximity to a wind turbine. Despite this general support for the concept of wind power in the public at large, local opposition often exists and has delayed or aborted a number of projects.
While aesthetic issues are subjective and some find wind farms pleasant and optimistic, or symbols of energy independence and local prosperity, protest groups are often formed to attempt to block new wind power sites for various reasons. This type of opposition is often described as NIMBYism ,  but research carried out in found that there is little evidence to support the belief that residents only object to renewable power facilities such as wind turbines as a result of a "Not in my Back Yard" attitude.
It has been argued that expanding use of wind power will lead to increasing geopolitical competition over critical materials for wind turbines such as rare earth elements neodymium, praseodymium, and dysprosium. But this perspective has been criticised for failing to recognise that most wind turbines do not use permanent magnets and for underestimating the power of economic incentives for expanded production of these minerals. Wind turbines are devices that convert the wind's kinetic energy into electrical power. The result of over a millennium of windmill development and modern engineering, today's wind turbines are manufactured in a wide range of horizontal axis and vertical axis types.
The smallest turbines are used for applications such as battery charging for auxiliary power. Slightly larger turbines can be used for making small contributions to a domestic power supply while selling unused power back to the utility supplier via the electrical grid. Arrays of large turbines, known as wind farms , have become an increasingly important source of renewable energy and are used in many countries as part of a strategy to reduce their reliance on fossil fuels. Wind turbine design is the process of defining the form and specifications of a wind turbine to extract energy from the wind.
The aerodynamics of a wind turbine are not straightforward. The air flow at the blades is not the same as the airflow far away from the turbine. The very nature of the way in which energy is extracted from the air also causes air to be deflected by the turbine. In addition the aerodynamics of a wind turbine at the rotor surface exhibit phenomena that are rarely seen in other aerodynamic fields. The shape and dimensions of the blades of the wind turbine are determined by the aerodynamic performance required to efficiently extract energy from the wind, and by the strength required to resist the forces on the blade.
In addition to the aerodynamic design of the blades , the design of a complete wind power system must also address the design of the installation's rotor hub , nacelle , tower structure , generator , controls, and foundation. These are becoming increasingly sophisticated as highlighted by a recent state-of-the-art review by Hewitt et al. From Wikipedia, the free encyclopedia. For the academic journal, see Wind Energy journal.
The conversion of wind energy into a useful form. Renewable energy portal Environment portal. Natural Gas Hydro Nuclear fission Oil 3. Non hydro renew. Main article: History of wind power. Main articles: Wind farm and List of onshore wind farms. Main articles: Offshore wind power and List of offshore wind farms. Play media.
Main article: Wind power by country. Global annual new installed wind capacity — in MW  : 3. China: 23, MW Worldwide new installed capacity , . China: , MW Worldwide cumulative capacity , . Main article: Variable renewable energy. Further information: Grid balancing. Main article: Wind power forecasting. Main article: Grid energy storage. See also: List of energy storage projects.
Some of the 6, turbines in California's Altamont Pass Wind Farm aided by tax incentives during the s. Further information: Microgeneration. Main article: Environmental impact of wind power. See also: Community debate about wind farms. Main articles: Wind turbine and Wind turbine design. See also: Wind turbine aerodynamics. Renewable energy portal Energy portal Wind power portal. Retrieved 23 May The last record was set in when over The new global total for wind power at the end of was National Grid.
Archived from the original PDF on 25 March Graham Sinden analysed over 30 years of hourly wind speed data from 66 sites spread out over the United Kingdom. He found that the correlation coefficient of wind power fell from 0. There were no hours in the data set where wind speed was below the cut-in wind speed of a modern wind turbine throughout the United Kingdom, and low wind speed events affecting more than 90 per cent of the United Kingdom had an average recurrent rate of only one hour per year.
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Bibcode : PNAS.. Environmental Research Letters. Bibcode : ERL University Journal of Engineering and Technology.