Renewable energy sources are the energy sources from nature which may be renewed; currently they are more and more used because they do not harm the environment. The most frequently used renewable energy sources are wind, sun and water.
Renewable energy sources may be divided into two main categories: traditional renewable energy sources such as biomass and large hydro power plants, and so called „new renewable energy sources“ such as the energy of Sun, wind, geothermal energy, etc.
The Sun provides to the Earth 15 thousand times more energy than the mankind manages to consume currently; but still there are some people on Earth who are freezing. It shows that renewable energy sources may and must be utilised better and that we should not worry about energy after the fossil fuels. Development of renewable energy sources (particularly wind, water, sun and biomass) is important for several reasons:
renewable energy sources have a very important role in reduction of carbon dioxide emission (CO2) to atmosphere. Reduction of CO2 emission to atmosphere is the European Union policy, so it may be expected that more European countries will have to accept that policy;
increase of renewable energy sources share increase energy efficiency of the system. It also contributes to safety in energy supply in a way that it reduces the dependence on import of energy raw material and electricity;
the expectations are that renewable energy sources would become competitive to conventional energy sources in a mid-term to a long-term period.