A process of converting steam to hydro-electric power through a process of allowing steam to displace water from a tank for operating a turbine or pelton wheel. The process allows hydro-electric power to be generated at a greatly increased efficiency. Preferably, two concrete, underground chambers are used to receive steam which exert pressure to displace the water. The process allows existing power plants to utilize excess steam to generate additional power, and thus greatly increase the overall efficiency of the plant. Solar energy heats the water to produce low pressure steam in a transparent enclosure, and further heats the vapor passing through transparent conduits leading into the underground chambers.