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 preferably a hydrocarbon oil derived from petroleum, which hot material is stored under an inert atmosphere at atmospheric pressure in a high temperature storage location means. Hot water as such, is also optionally stored, in hot storage means which hot water has either previously heated the LVP organic material or which hot water has itself been only slightly heated with low pressure extraction steam as BFW. Such stored hot water, at a temperature of 210.degree.F. during periods of high power demand, is itself used as boiler feed water and is heated by a moving stream of hot LVP organic material moving from high temperature storage location means to low temperature storage location means and sent to the boiler. 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 ocation means, use of extraction steam for BFW reheat being curtailed and such untapped extraction steam being allowed instead to expend itself fully in the turbines. The boiler at all times receives a constant amount of uniformly preheated BFW. Alternatively, or simultaneously, the stored hot LVP organic material can be used to raise intermediate pressure steam and this steam can be injectable into the steam turbines between appropriate stages or into auxiliary turbines used solely for this purpose.