Interest in thermoelectrics for waste heat recovery and geothermal energy has flourished in recent years, but China's installed geothermal power capacity has barely increased. Carbon neutralization brings new opportunities for geothermal energy development and utilization. This work investigates the innovation in geothermal power generation technology as an important part of accomplishing the carbon neutralization goals. Thermoelectric generators (TEG) could be used for geothermal power generation and waste heat recovery, thus converting low-grade thermal energy into electricity. Since TEG works in a very simple manner as it converts thermal energy into electricity, it could fill part of the technical gaps in the development and utilization of low to medium-temperature geothermal resources. For this work, we conducted the field tests of TEG using industrial waste heat from a gas power plant. The temperature was around 80 °C. The TEG units were hierarchically modular and easily expandable to fit any scale. The power output and efficiency of TEGs were influenced by temperature difference and fluid flow rate. At appropriate flow rates, a TEG unit with a volume of about 0.03 m3 could generate a power of 150 W at a temperature difference of 60 °C. The power density and the power per unit area of the TEGs were investigated at various temperature differences and were compared with those of diesel generators and photovoltaic (PV) panels, respectively. Additionally, to provide guidance and clues for TEG at commercial scales, we estimated the costs of TEG fabrication, installation, and also the Levelized Cost of Electricity (LCOE) at various temperature differences. Many previous studies reported that TEG was mostly used for low-power microelectronic devices, but results from this study demonstrate the feasibility and the potential of TEG for large-scale geothermal power generation and waste heat recovery.

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