A wind turbine is a modern day windmill, usually used to generate electricity. Typically modern wind turbines look a little like old fashioned windmills with three arms instead of four, and much slimmer due to the use of modern construction materials.

There are many reasons for modern interest in windmills. Unlike fossil fuel burning power plants, they do not pollute, contribute to global warming, or use up non renewable resources. They do not involve the traditional concerns about the safety of nuclear power or radioactive waste disposal problems. They have much less impact on the environment than hydroelectric power. Often land being used for wind turbines can be used for other purposes as well, since they don't have large footprints.

Clearly there must be disadvantages as well, or else you would see everyone using it. Wind power is intermittent and unpredictably so, since you don't know exactly when the wind will be blowing. It is still a little more expensive than other forms of power, although this is changing as fossil fuel prices rise and wind technology advances.

Some of these problems can be ameliorated by hybrid power systems, reverse metering, and other methods. Sometimes they are not as important, such as for certain uses of [wind power at remote locations.