Wind energy is the kinetic energy produced by the wind. It is transformed into electricity by devices called wind turbines (special windmills).

Advantages: it is an inexhaustible energy source and, once the installation is finished, it is free. Furthermore, it does not cause pollution: because there is no combustion, it does not produce acid rain, it does not contribute to the greenhouse effect, nor does it destroy the ozone layer or generate waste.

Disadvantages: it is an intermittent energy source, as it depends on the regularity of the winds. Also the wind turbines are large and expensive. The silhouettes like those in the following picture are becoming more popular every day.