Wind is indeed an inexhaustible energy source. Winds are created by the sun, which heats up regions of Earth unevenly. This uneven heating creates air pressure imbalances. As highly pressurized air rushes toward low-pressure regions, wind is created. In modern times wind energy has been employed mainly to drive electric turbines. The electricity produced by the generator can be used to power homes directly or sent to the utility grid for use by other electricity consumers. Many energy companies are currently investing in wind technologies. Despite its advantages, wind energy has many critics. One of the criticisms leveled at wind power is its unreliability. The wind does not blow constantly in all places at all times, opponents point out. Often, it is too weak to turn turbine blades, even in windy regions. At other times the wind is too strong; if the turbines are not turned off, strong winds can damage or destroy them. Other commentators object to wind power being called an environmentally friendly energy source. They argue that the blades of windmills present a danger to birds. Many critics also oppose wind energy on the grounds that erecting turbines tall enough to capture wind mars the beauty of landscapes. - Introduction.