Wind energy represents a particular form of solar energy and is caused by the uneven heating of the earth's surface by the sun. The sun emits radiation toward the Earth that equals 100.000.000.000.000 kWh. Approximately 1 or 2 percent of this radiation are turned into wind energy.
The power of the wind has been exploited by humans for a very long time. Nowadays this energy is even more attractive because it does not produce any waste or air pollution while operating and does not have an impact on human health. Wind is a primary energy source, that could be used almost everywhere around the world and the nature provides us with it for free.
The the current wind energy development began with the construction and the evolution of small wind turbines. Those small devices were assigned to simple operations. However, as an energy source they completely lost their intended meaning after the gradual capacity increase of the modern turbines. Currently, all bigger turbines provide energy for electricity power grid.
In the following years wind energy recognized immense growth with annual increase of 30 percent. The world wind power installed capacity has reached 74.000 MW by the end of 2006. Nowadays it is a common practice to build wind power plants with power of 1.5 to 2.5 MW. The world biggest turbine generates power of 6 MW (Germany). Up-to-date wind turbines produce very little noise and are being accepted by their surroundings and big wind farms reach up to 400 MW capacity.