Wind energy

Air flow may be trapped and exploited to actuate the wind turbines. Modern wind turbines can reach outputs from 600 kW to 5 MW, while the turbines with the capacity about 1.5 to 3 MW became the most frequently used for the commercial purposes. The output of the wind turbine is directly proportional to the third power of the speed of wind which means that even with the slight rise in the wind speed the output of machines increases dramatically. The high altitude areas or those close to the shore, where winds are stronger and more stabile, are   mostly preferred from the point of the wind farms construction. Though the wind energy exploitation demonstrates the fastest grow among all renewable resources, it assumes less than 0.5% of the global energy production. During the previous ten years period  the overall installed capacity has increased from 2 500 MW in the year 1992 to more than  40 000 MW by the end of the year 2003, and the annual growth has been close to 30 %.  With the rise in the wind turbines access, they start to install them into the networks of some public schools with the objective to reduce the fees for electricity. With regard to the non-stabile and discontinuous nature of the output from wind turbines, for Europe they declared mean output equal to 25 % of the installed output (25-percent output factor), however under the favourable wind conditions locally they state even 35 % and more. This basically means that 5 MW turbine installed in Europe would provide in average 1.7 MW output annually, or its nominal output in course of 3 months.

Wind energy

Globally, the long term energy potential of the wind energy is estimated to be 5-times of the recent energy production or 40- times of the recent demand. It would of course require large area of land for the wind turbines erection, especially in the windy regions. The experience with the sea bound sources exhibit 90% higher average wind speed in comparison to the inland ones. It means that right these areas could contribute more significantly to the development of the wind power stations. This number may also be increased by erecting such turbines in the higher altitudes.

The wind intensity close to the earth surface is changeable and can not assume the continuous electricity supply if not being combined with other energy sources or accumulation systems. Some estimates say that 1000 kW wind turbine is capable to assume only 333 kW of the continuous output. Though this fact may be slightly improved due to the technological development the defenders of the wind energy rather propose the combination with other energy sources or exploiting the storing technologies. As the most suitable use would be the application in the system with the sufficient output reserve, as the hydropower station, supplementary source, for example desalination power station, to mitigate the economical effect of the wind instability.

However, the wind energy is renewable and does not produce in course of its operation any greenhouse gas as carbon dioxide or methane.

Windy park Cerová

In the Slovak Republic we have recently (y. 2008) only 5.14 MW of the installed output in the wind energy, namely in Veterný park Cerová (4x660 kW), Ostrý vrch (500 kW) and Skalité (4x500 kW). This does not represent even 0.1 % of the overall installed output. Construction of the further sources is the subject of permanent discussions. Main obstacles represent in particular disagreement of the superior electrification systems due to the instability of such type of energy and lack of the regulatory reserves in other sources.