Thermal energy storage and utilization system

The power output from a nuclear power plant or fossil fuel power plant operating under constant reactor (or furnace) and boiler conditions is varied by regulating the rate of turbine extraction steam and primary high pressure steam used to heat boiler feed water (BFW). During periods of low power demand excess extraction steam is drawn off to heat excess quantities of boiler feed water. One portion of the BFW is fed to the boiler while the other portion is used to reheat a low vapor pressure (LVP) organic material which hot material is stored under an inert atmosphere at atmospheric pressure in a high temperature storage location means. During periods of high power demand BFW preheat duties would be taken over entirely by the moving LVP organic material, moving from hot to cold storage location means, use of extraction steam for BFW reheat being curtailed and such untapped extraction steam being allowed instead to expand itself fully in the turbines. The boiler at all times receives a constant amount of uniformly preheated BFW.