A power generator having an impeller configured to facilitate the translation of balls through a ball-actuated turbine and facilitate the transfer of water to drive a water-actuated turbine. The impeller is located within a fluid compartment and creates a turbulent water flow, which generates an inverted vortex. The impeller includes a central bore having an outlet communicating with the fluid compartment and an inlet communicating with a feed space. An array of balls is supplied to the impeller bore via the feed space and traverses the bore in response to the vortex. The balls ascend through the fluid compartment and an upper water tank. At a higher elevation, the ascending balls are routed downstream via gravity to the ball-actuated turbine, while water is routed downstream via gravity to the water-actuated turbine. After performing their respective turbine-driving actions, the water and balls recirculate to the feed space to repeat the cycle.