A method and apparatus for producing energy is provided for generating renewable energy. Captive compressed fluid cycles between two coupled containers through a motive power source. The captive compressed fluid flows between the containers in response to a difference in the pressure of the compressed fluid within the first container compared to the pressure of the compressed fluid within the second container. This pressure differential develops as the compressed fluid within the first container experiences a temperature change of a differing percentage magnitude or direction than the compressed fluid within the second container over the same period of time. The differing percentage temperature fluctuations result as the containers are provided dissimilar exposure to natural renewable or man-made energy sources or are insulated therefrom. A continuous supply of additional compressed fluid is not required, nor is fluid routinely vented to the atmosphere.