Abstract: Various embodiments include a thermal storage system for storing energy in a graphite thermal storage structure and a thermal shutter assembly configured to control the transmission of heat from the graphite thermal storage structure to a thermal energy receiver, such as a heat exchanger or material processing crucible. A thermal storage block, which may be made of graphite, may be isolated by insulation except for the thermal shutter assembly. Energy may be stored in the graphite thermal storage block by applying energy to the block to raise its temperature to maximum operation temperature. Stored energy may then be harvested in a controlled manner by a control system actuating the thermal shutter to expose the thermal energy receiver to thermal radiation.