Wind power

is the use of wind energy to generate useful work. Historically, wind power was used by sails, windmills and windpumps, but today it is mostly used to generate electricity. This article deals only with wind power for electricity generation. Today, wind power is generated almost completely with wind turbines, generally grouped into wind farms and connected to the electrical grid. In 2022, wind supplied over 2,304 TWh of electricity, which was 7.8% of world electricity. With about 100 GW added during 2021, mostly in China and the United States, global installed wind power capacity exceeded 800 GW. 32 countries generated more than a tenth of their electricity from wind power in 2023 and wind generation has nearly tripled since 2015. To help meet the Paris Agreement goals to limit climate change, analysts say it should expand much faster – by over 1% of electricity generation per year. Wind power is considered a sustainable, renewable energy source, and has a much smaller impact on the environment compared to burning fossil fuels. Wind power is variable, so it needs energy storage or other dispatchable generation energy sources to attain a reliable supply of electricity. Land-based (onshore) wind farms have a greater visual impact on the landscape than most other power stations per energy produced. Wind farms sited offshore have less visual impact and have higher capacity factors, although they are generally more expensive. Offshore wind power currently has a share of about 10% of new installations. Wind power is one of the lowest-cost electricity sources per unit of energy produced. In many locations, new onshore wind farms are cheaper than new coal or gas plants. Regions in the higher northern and southern latitudes have the highest potential for wind power. In most regions, wind power generation is higher in nighttime, and in winter when solar power output is low. For this reason, combinations of wind and solar power are suitable in many countries.

Once called windmills, the technology used to harness the power of wind has advanced significantly over the past ten years, with the United States increasing its wind power capacity 30% year over year. Wind turbines, as they are now called, collect and convert the kinetic energy that wind produces into electricity to help power the grid. Wind energy is actually a byproduct of the sun. The sun’s uneven heating of the atmosphere, the earth’s irregular surfaces (mountains and valleys), and the planet's revolution around the sun all combine to create wind. Since wind is in plentiful supply, it’s a sustainable resource for as long as the sun’s rays heat the planet. In addition, because wind power is a growing industry, it’s adding jobs to communities around the country. Currently, there are utility-scale wind plants in 41 states that have created more than 100,000 jobs for Americans. Learn more about the wind industry here, from how a wind turbine works, to the new and exciting research in the field of wind energy.

• How wind turbines work
• How distributed wind wo rks
• Advantages and challenges of wind
• Wind energy use throughout history
• Current research and development
• Wind energy benefits (slideshow)
• Wind energy impacts (slideshow)

This aerial view of a wind turbine plant shows how a group of wind turbines can make electricity for the utility grid. The electricity is sent through transmission and distribution lines to homes, businesses, schools, and so on. View the wind turbine animation to see how a wind turbine works.

Wind is air movement in the Earth's atmosphere. In a unit of time, say 1 second, the volume of air that had passed an area A is Av. If the air density is ρ, the flow rate of this volume of air is MΔt=ρAv, and the power transfer, or energy transfer per second is P=12MΔtv2=12ρAv3. Wind power is thus proportional to the third power of the wind speed; the available power increases eightfold when the wind speed doubles. Change of wind speed by a factor of 2.1544 increases the wind power by one order of magnitude (multiply by 10).

The global wind kinetic energy averaged approximately 1.50 MJ/m2 over the period from 1979 to 2010, 1.31 MJ/m2 in the Northern Hemisphere with 1.70 MJ/m2 in the Southern Hemisphere. The atmosphere acts as a thermal engine, absorbing heat at higher temperatures, releasing heat at lower temperatures. The process is responsible for the production of wind kinetic energy at a rate of 2.46 W/m2 thus sustaining the circulation of the atmosphere against friction.

Through wind resource assessment, it is possible to estimate wind power potential globally, by country or region, or for a specific site. The Global Wind Atlas provided by the Technical University of Denmark in partnership with the World Bank provides a global assessment of wind power potential.Unlike 'static' wind resource atlases which average estimates of wind speed and power density across multiple years, tools such as Renewables.ninjaprovide time-varying simulations of wind speed and power output from different wind turbine models at an hourly resolution. More detailed, site-specific assessments of wind resource potential can be obtained from specialist commercial providers, and many of the larger wind developers have in-house modeling capabilities.

The total amount of economically extractable power available from the wind is considerably more than present human power use from all sources. 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. Different locations will have different wind speed distributions. The Weibull model closely mirrors the actual distribution of hourly/ten-minute wind speeds at many locations. The Weibull factor is often close to 2 and therefore a Rayleigh distribution can be used as a less accurate, but simpler model.

Reference: https://en.wikipedia.org/wiki/Wind_power

Kitshanaphon chanchai M5/2 No.30