Efficiency of exploitation, preparation and conversion of primary energy reserves and hydropotentials

Energy resources in use today, except hydropotentials, are unrecoverable and therefore their use as rational as possible is crucial in all exploitation stages up to the final use. The paper treates using i.e. efficiency of using those reserves through the stages of exploitation, preparation and conversion in existing plants and by application of todays technology phases. Considering those phases, possible development with regard to increase of future efficiency doefficient is estimated, based on so far available information on advance of research work in those fields. Whenever we had available reliable data, comparison has been made in our country with the efficiency state of those three phases