Wind turbine

A wind turbine is a device that converts the kinetic energy of wind into electrical energy. As of 2020^[update], hundreds of thousands of large turbines, in installations known as wind farms, were generating over 650 gigawatts of power, with 60 GW added each year.^[1] Wind turbines are an increasingly important source of intermittent renewable energy, and are used in many countries to lower energy costs and reduce reliance on fossil fuels. One study claimed that, as of 2009,^[update] wind had the "lowest relative greenhouse gas emissions, the least water consumption demands and the most favorable social impacts" compared to photovoltaic, hydro, geothermal, coal and gas energy sources.^[2]

Smaller wind turbines are used for applications such as battery charging and remote devices such as traffic warning signs. Larger turbines can contribute to a domestic power supply while selling unused power back to the utility supplier via the electrical grid.^[3]

Wind turbines are manufactured in a wide range of sizes, with either horizontal or vertical axes, though horizontal is most common.^[4]