From the current Serbian energy security supply situation it is hard to imagine how important would be the construction of two new reversible hydro power plant. Projected output power of this two new project ideas is 3080MW (2400+680MW) which would represent 37% of current Energy company of Serbia (EPS) capacities and what would this projects mean for Serbian economy in general. Trend of droughts and problems coming from low accumulation in hydro power plants, projected demand increase vs low capacities in the region and price volatility would make this project important even for region of Balkans.