Expanding Geothermal Energy Utilization Through a New Solid-State Thermoelectric Power Generator

Abstract

Commercial geothermal power plants typically operate at thermal to electric conversion efficiencies of ~10-18%, constrained by parasitic loads and system level losses. This work presents a solid-state thermoelectric power generation system that recovers geothermal waste heat by directly converting thermal energy into electricity via the Seebeck effect. Operating without moving parts, the system offers a compact, reliable, and near maintenance free solution that is readily retrofittable to turbine exhausts, separator units, wellhead facilities, and heat rejection stages, where low to medium temperature thermal energy is routinely discharged in geothermal and other industrial processes. A field deployable thermoelectric power cell was designed, fabricated, and experimentally evaluated under laboratory thermal conditions, producing ~228 W from a scaled down 4-module Mk III configuration at a temperature difference of ~71 °C, corresponding to a projected output of ~1.02 kW for a fully populated 16-module stack. Building on this experimentally validated scaling behavior, the upgraded Mk IV architecture is projected to deliver ~10 kW using 16-module at a temperature difference of 220 °C under field conditions, with conversion efficiencies ranging from ~0.83% to 3.88% over the evaluated operating range of 50-225 °C.