The alkali metal thermo-to-electric converter (AMTEC) has reached a level of technological maturity which would allow its use in a constant, unattended thermal source, such as geothermal field. AMTEC cells using sodium as a working fluid require heat input between 500 and 1000C to generate power. The present state-of-the-art is capable of 15% efficiency with 800C heat input and has demonstrated 18% efficiency for single cells. This paper discusses the basics of AMTEC operation, current drilling technology as a cost driver, design of modular AMTEC power units, heat rejection technologies, material considerations, and estimates of power production from a geothermal AMTEC concept.
