ENERGY STORAGE BY MEANS OF FLUID HEAT RETENTION MATERIALS KEPT AT ATMOSPHERIC PRESSURE

More efficient use of the heat output of a constant output nuclear reactor, or constant output fossil fuel furnace, and boiler in an electricity generating plant that uses a multi-stage steam turbine and employs turbine extraction steam to preheat boiler feed water, is obtained by storing, during a period of low power demand, excess thermal energy in a liquid low vapor pressure thermal energy retention material maintained at high temperature at atmospheric pressure, and then, during a period of peak power demand, reducing or terminating the extraction of turbine steam and using the stored hot energy retention material, through heat exchange flow, to perform power plant support heating functions, including boiler feed water preheat and/or turbine interstage steam. The liquid heat retention materials include low vapor pressure organic materials such as hydrocarbon oils and aromatic ethers as well as molten metals, molten metal salts and molten metal hydroxides such as sodium hydroxide or potassium hydroxide.