Wind is the kinetic energy of molecules in the air. Wind has powered ships and mills for centuries or longer.

Modern windmills convert the wind into rotational energy by allowing the air molecules to bombard the blades, turning them. The blades are connected to turbines, which generate electricity from that rotational energy.

Wind energy is one of the cleanest forms of energy available because it doesn’t require a fuel or produce greenhouse gas or other bi-products, outside of those from production and maintenance of equipment and transmission.

Wind turbines themselves take up only a small area compared to their generating potential, making it possible to install them on agricultural, forest, or grazing lands.


In just ten years, wind power in the United States grew more than ten-fold, from just over 2,000 megawatts in 1999 to more than 34,000 megawatts in 2009, when wind accounted for 9 percent of renewable energy produced in the country and more than geothermal and solar combined.

Here’s an animated map of wind development from 2000 to 2010.

Texas, Iowa, and Minnesota had the greatest wind capacity in 2010. Additionally, at least 27 other states used wind to generate electricity that year.


Wind is an intermittent resource, meaning that the windmills can’t continuously and predictably produce energy. They only work when the wind blows, and they can only work as hard as the wind is blowing at that time.

Research is ongoing into predicting what regions of the country have significant wind resources suitable for wind development, a process that requires computer programming and meteorological knowledge.

Furthermore, public and private researchers are working to produce better models of wind on an hourly, daily, and seasonal basis to make it easier for wind energy producers to forecast their output and sell it ahead of time.

Another major hurdle to wind power is that it is expensive compared with fossil fuel-based electricity. Modern windmills cost a lot to design and build, especially as they have to be strong enough to endure extreme weather, even though they will mostly operate in moderate weather. That makes competing with other energy sources difficult without government intervention.

Some people don’t like the way windmills look, and windmills can also kill bats and birds, though newer designs have slower and less deadly blades. A 2010 study published in the Journal of Ornithology estimated that windmills kill around 440,000 birds every year. However, the same study showed that house cats kill more than 1,000 times that number, as many as 500 billion per year.