Abstract: A reversible system for generating electric power includes a first reservoir initially containing a predetermined volume of water, a second reservoir initially being substantially empty, a turbine selectively connectable to the first and second reservoirs through multiple valves, and a generator connected to the turbine to generate electric power. An air bank selectively provides pressurized air to the first reservoir during an initial operational time period to increase an internal pressure of the first reservoir. An air compressor operates only at times other than the initial operational time period to charge the air bank. At least a first valve is opened during the initial operational time period to enable the water to flow from the first reservoir through the turbine to the second reservoir, in response to the increased internal pressure, causing the turbine and the generator to generate electric power.