A thermal energy storage apparatus adapted to receive heat source input for the development and substantially continuous supply of thermal energy to a Stirling engine for the transfer of said thermal energy to electrical and/or mechanical energy, even during periods when heat source input is intermittent or unavailable for a period of time. The apparatus includes a series of elongate canisters containing silicon metalloid and made of refractory material. The canisters are interlaced with a thermal energy absorbing material in communication with a wicking material to which the Stirling engine is in communication.