Public stimulation of renewable energies

In the 21(st) century renewable energies should substitute the energies obtained from conventional sources. However, many obstacles slow down their introduction (technological, economic, legal), among which the biggest ones are - high level of competition and supremacy of conventional energy. As market mechanisms did not succeed in contributing to the bigger and faster expansion of renewable energies, the government in developed countries is obliged to give them public support applying stimulating instruments. Economic and ecological reasons of this support have been pointed out and advantages and disadvantages regarding the stimulating instruments (guaranteed purchase price and competitive bids) have been analysed.