Material Selection, Design Configuration, and Economic Considerations in Thermoelectric Generators: A Comprehensive Review

Thermoelectric generators (TEGs) are solid-state renewable energy devices that directly convert waste heat into electricity without moving parts, offering durability, scalability, and silent operation. Consequently, this review provides a critical overview of TEGs, emphasizing their materials, design, and economics. In addition, it critically examines key factors that influence TEGs performance, such as Figure of Merit (ZT), leg geometry, and contact resistance, and their implications for large-scale deployment. Recent material developments are highlighted, including Bi₂Te₃ (ZT ≈ 1.1 at 300 K), PbTe (ZT ≈ 1.8 at 900 K), and SiGe alloys (ZT ≈ 1.5 at 1000 K), as well as nanostructured compounds exceeding ZT = 2.0. Design innovations such as trapezoidal legs (+ 2.3% efficiency) and diamond-shaped legs (stress reduction > 15%) demonstrate how geometry improves TEGs performance and durability. Beyond the engineering details, the study elaborates on the economic aspects of TEGs' application demonstrating their compatibility in sustainable energy systems. Although their costs vary widely (1.8–62.5 $/W) depending on material selection and device design, TEGs are most favorable in small-scale applications (< 0.1 kW). Notably, high-ZT materials can enhance overall performance without a proportional increase in cost. For hybrid TEG systems, most reported LCOE values remain below $1/kWh, highlighting their strong techno-economic potential. Furthermore, integration with concentrated photovoltaic (CPV) systems and the incorporation of advanced cooling strategies significantly improve overall efficiency and economic performance.