Abstract: A continuous power system provides a continuous supply of power to a load in the event that primary power fails or is degraded. The continuous power system includes an electrical machine, a turbine and a flywheel coupled to a shaft. When utility power is present, the machine operates as a motor to drive the shaft. During outages, the electrical machine operates as a generator to provide power to the load. Kinetic energy stored in the flywheel drives the shaft during initial power interruptions. During further short-term interruptions, a thermal energy supply (or thermal storage device) is used to provide vaporized liquid to the turbine so that the turbine drives the shaft. If the power loss or failure is extended, the turbine is driven by vapor produced by an evaporator heated from an external fuel supply. Numerous methods and apparatus are also described for reducing system losses and improving overall performance.