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Page 14 of 17 Lekbir et al. Energy Mater. 2025, 5, 500101 https://dx.doi.org/10.20517/energymater.2025.46

Table 7. Energy assessment and environmental impact for the different TEG modules
Total CEC for TEG module Maximum output Energy production (kWh/20 CO amount Equivalent kg.CO
Ref 2 2
(MJ) (W) year) (kg) /kWh
TEG1 1,279.66 0.062 10.85 107.99 9.96
TEG2 3,566.03 0.397 69.52 300.9 4.33
TEG3 2,979.93 0.494 86.47 251.5 2.91
TEG4 4,185.63 1.119 196.05 353.22 1.8
TEG5 3,530.43 0.574 100.62 297.93 2.96
TEG6 3,842.06 0.073 12.78 324.23 25.37
TEG7 3,015.06 0.091 15.9 254.44 16
TEG8 6,678.43 0.573 100.45 563.58 5.61

However, increasing the ΔT can enhance the energy output of TEGs and thus reduce their equivalent
emissions. Indeed, at ΔT = 100 K, the equivalent CO emissions for TEG1 to TEG8 are significantly reduced
2
to approximately 0.114, 0.201, 0.135, 0.085, 0.14, 0.29, 0.187, and 0.26 kg CO /kWh, respectively. Therefore,
2
the environmental sustainability of different TEG modules is highly dependent on both material selection
and operating conditions, particularly the ΔT.

Overall, the design of TEG modules requires careful consideration of leg dimensions and the number of
thermocouples. Shorter legs with a high number of thermocouples emerge as the most effective choice for
enhancing power output. Conversely, longer legs with low thermocouple numbers may be preferable for
reducing the environmental impact associated with the manufacturing phase. Therefore, the optimal trade-
off depends on the specific objective, whether prioritizing higher power output or sustainability. In addition,
the TEG module dimensions play a critical role in balancing power output, space efficiency, and thermal
management. The choice of a specific TEG module should be based on the intended application, available
heat source, and installation constraints.

CONCLUSION
This study presents a comprehensive assessment of TEG materials and system geometries, highlighting the
critical trade-offs between performance and environmental sustainability. Through life cycle assessment, we
demonstrate that material selection substantially influences embodied energy and GHG emissions, with
SiGe-based TEGs exhibiting the highest carbon footprint. PbTe-based TEGs offer the highest energy output,
while Bi Te -based modules provide a balance between performance and environmental impact. The PSO-
3
2
based optimization approach significantly improves power output while reducing environmental impact,
underscoring the importance of multi-objective optimization in sustainable TEG development. The findings
suggest that optimizing system geometry, particularly through thermocouple count and leg dimensions
adjustments, enhances energy conversion and eco-friendliness. These results offer actionable insights for
researchers, engineers, and policymakers aiming to develop high-performance, environmentally responsible
thermoelectric energy systems.

DECLARATIONS
Acknowledgments
The authors gratefully acknowledge the financial assistance provided for the successful completion of this
work.