Wind power most commonly refers to electrical energy generated through the harnessing of the motor energy of air in motion (wind). It is more accurately referred to as wind energy. This energy is collected through a network of one or more devices designed specifically for the purpose of generating wind energy. Most wind turbines have appearances similar to airplane propellers or windmills. Newer, more efficient models may use a design more similar to a modified sail, turbine fan or pinwheel. The harvesting of wind energy for commercial sale is referred to as wind farming. Usable wind turbines may be as small as a foot in diameter and fit in a shirt pocket. Large commercial generators may use fans with blades more than a hundred feet in height.

Wind turbines were common in rural areas across North America during the 1930s and 1940s when these areas were not yet served by electric utilities, and they may be set to make a major comeback in the 21st century. The rusting steel windmills seen on farms throughout North American agricultural regions are relics of this period, and most of them once powered electrical generators on the farms they served.

Wind speeds as low as 5 mph can effectively drive a well-constructed wind turbine, but in most locales usable energy can only be produced about 30 percent of the time. Tidal turbines, which harness the water currents produced by tidal flows, may become a more common source of pollution-free energy over the next few decades, but at this time wind energy is the fastest-growing source of pollution-free renewable energy.

Costs for wind farming hardware have decreased with the steady rise in unit sales of wind turbine generators, and costs will likely continue to fall throughout decade one. Wind energy is currently less expensive to produce than nuclear energy was in the early 1980s. Whenever fossil fuel prices rise for more than short periods, more regions of North America institute new support policies and energy purchasing schemes that make the installation and operation of commercial wind turbine generators practical for small-scale producers. Some agricultural regions are even betting substantial sums of public money on small-scale wind farming as a way to supplement agricultural income in the fight to save family farms in the US and Canada, and decrease long-term reliance on fossil fuels and other sources of non-renewable energy.

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