Wind power

Wind power harnesses the movement of air to perform useful tasks. While it once powered sails, windmills, and water pumps, today it is almost entirely used to generate electricity. This is done with wind turbines, which are typically arranged in groups called wind farms and linked to the power grid.

In 2025, wind energy supplied roughly 2,700 terawatt-hours of electricity, accounting for over 8% of the world’s total. Around 100 gigawatts of new capacity were added in 2021, mostly in China and the United States, pushing the global total past 800 gigawatts. By 2024, thirty countries were getting more than a tenth of their electricity from wind, and global wind generation has nearly tripled since 2015. To meet the Paris Agreement’s climate goals, analysts say wind power must grow much faster—by more than 1% of global electricity generation each year.

Wind is a sustainable, renewable energy source with a much smaller environmental footprint than burning fossil fuels. However, its output varies, so reliable electricity supply requires energy storage or other dispatchable power sources. Onshore wind farms tend to have a greater visual impact on the landscape than most other power plants per unit of energy produced. Offshore wind farms are less visually intrusive and often have higher capacity factors, but they are generally more expensive. Currently, offshore installations make up about 10% of new wind capacity.

Wind power is among the cheapest sources of electricity per unit of energy. In many places, new onshore wind farms are cheaper to build than new coal or gas plants. The highest wind potential is found in higher northern and southern latitudes. In most regions, wind generation peaks at night and in winter, when solar output is low, making wind and solar a good combination for many countries.

Wind is simply moving air in the Earth’s atmosphere. The power available from the wind depends on the cube of its speed: if wind speed doubles, the available power increases eightfold. A speed increase by a factor of about 2.15 multiplies the power by ten. From 1979 to 2010, the global average kinetic energy of wind was about 1.50 megajoules per square meter—1.31 in the Northern Hemisphere and 1.70 in the Southern. The atmosphere works like a heat engine, absorbing heat at high temperatures and releasing it at low ones, which generates wind kinetic energy at a rate of 2.46 watts per square meter, sustaining atmospheric circulation against friction.

Wind resource assessments can estimate potential globally, by country, or for a specific site. The Global Wind Atlas, created by the Technical University of Denmark with the World Bank, offers a worldwide overview. Unlike static atlases that average wind speed and power density over many years, tools like Renewables.ninja simulate hourly wind speeds and power output for different turbine models. More detailed, site-specific assessments are available from commercial specialists, and many large wind developers have their own in-house modeling.

The total economically extractable wind power is far greater than current human energy use from all sources. But wind strength varies, so an average speed alone doesn’t tell you how much energy a turbine at that location could produce. To evaluate potential sites, a probability distribution is often fitted to observed wind data. The Weibull distribution closely matches actual hourly or ten-minute wind speeds at many locations. Since the Weibull shape factor is often near 2, a simpler Rayleigh distribution can be used as a reasonable approximation.

A wind farm is a collection of turbines at a single location. Large farms may have hundreds of turbines spread over a wide area, with the land between them used for farming or other purposes. Wind farms can also be built offshore. Nearly all large turbines share the same design: a horizontal-axis machine with an upwind rotor and three blades.