Wind energy is the process by which the wind generates mechanical power or electricity. People have been using energy from the wind for hundreds of years to pump water or grind grain. Today, wind turbines generate electricity. Wind power has a relatively high output, but only a fraction of its potential is currently used. Wind power plants cannot produce power on demand—their output depends on how hard the wind blows. Wind power often supplements other power sources. Wind power plants are also not feasible for all geographical locations. For example, very cold areas may not be ideal for wind power because of a small chance for ice thrown off the turbine blades.
Wind is a form of solar energy. The sun’s radiation heats different parts of the Earth at different rates—most notably during the day and night—influenced by the shape of the planet’s terrain, bodies of water, and vegetation. Hot air rises, reducing the atmospheric pressure at the Earth’s surface, and cooler air draws in to replace it. The result is wind.
Wind energy does not produce harmful greenhouse gases or waste products. According to the American Wind Energy Association, wind reduces emissions. One modern turbine could prevent 1,500 tons of carbon dioxide from releasing into the atmosphere in the US each year.
A common concern about wind power plants is noise: Do huge turbines make a lot of noise when they are spinning? While turbines do make noise, it is generally not loud enough to be disruptive to people’s day-to-day activities. Earlier turbine models were much noisier than today’s models, which have been redesigned to be more streamlined and efficient (and considerably quieter). The mechanical components of wind turbines do make some noise, but since the nearest houses are usually at least 300 meters/984 feet away, the noise that can be heard inside the houses would be comparable to that inside a quiet, air-conditioned office.
Wind turbines’ turning blades can cast a moving shadow on nearby buildings, called “shadow flicker.” The American Wind Energy Association says wind power plant developers can calculate whether a flickering shadow will fall on a given location near a wind farm and how many hours in the year it will do so. This makes it possible for developers to build turbines in locations that will not cast a shadow on houses.