Abstract: Method and system for generating electric power utilizing a coolant circuit, in which a coolant is evaporated at a lower level position, allowed to rise via tubing to a higher level position, liquified at the higher level position, and allowed to flow down to the lower level position in tubing where it impinges a hydraulic turbine connected to a generator. The preferred embodiment includes a vertical tube system of approximately 3000 m length, composed of a long tube for rising vapors and fall tubes for falling liquid coolant. Multiple cooling systems located at the higher level position, including a counterflow cooling system, forced-draught type air cooler, and a step-by-step cooling process, are utilized to liquify the coolant and provide working vapor to power the cooling systems. The coolant is composed to C.sub.3 H.sub.8 and NH.sub.3, which is varied on a percent composition basis to match atmospheric weather conditions.