Abstract: A method and apparatus uses energy in an energy output system having a main power source, an energy transmission system and a mechanical output. A first portion of energy generated with the main power source is used to drive the mechanical output under operating conditions. The unused second portion of the energy is diverted to an energy storing means. The second portion of energy is then stored and regenerated on demand. The energy may be used directly to augment the energy requirements in the energy output system during peak periods. In a specific embodiment, a compressed air system is used for storing the energy not used in driving a mechanical output connected to the power source by an energy transmission assembly. The energy transmission in the energy output system is a hydraulic fluid transmission system. A hydraulic fluid diverting mechanism is used to maintain the flow of hydraulic fluid to the mechanical output and to the compressed air energy storage system.