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Concentrating solar thermoelectric generators with a peak efficiency of 7.4%


Concentrating solar power normally employs mechanical heat engines and is thus only used in large-scale power plants; however, it is compatible with inexpensive thermal storage, enabling electricity dispatchability. Concentrating solar thermoelectric generators (STEGs) have the advantage of replacing the mechanical power block with a solid-state heat engine based on the Seebeck effect, simplifying the system. The highest reported efficiency of STEGs so far is 5.2%. Here, we report experimental measurements of STEGs with a peak efficiency of 9.6% at an optically concentrated normal solar irradiance of 211 kW m−2, and a system efficiency of 7.4% after considering optical concentration losses. The performance improvement is achieved by the use of segmented thermoelectric legs, a high-temperature spectrally selective solar absorber enabling stable vacuum operation with absorber temperatures up to 600 C, and combining optical and thermal concentration. Our work suggests that concentrating STEGs have the potential to become a promising alternative solar energy technology.

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Figure 1: CSTEG concept and proof-of-concept experiment.
Figure 2: Performance characteristics of a STEG optimized for high optical concentration.
Figure 3: Performance characteristics of a STEG optimized for moderate optical concentration.
Figure 4: Theoretical predictions of STEG efficiencies and corresponding optimal solar absorber temperatures.


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This material is partially based upon work supported as part of the Sunshot Initiative funded by the US Department of Energy, Office of Energy Efficiency & Renewable Energy under Award Number: DE-EE0005806 (for device engineering) and based upon work supported as part of the Solid State Solar-Thermal Energy Conversion Center (S3TEC), an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number: DE-SC0001299/DE-FG02-09ER46577 (for materials).

Author information




D.K. carried out modelling and simulation, CSTEG fabrication and experiments, and prepared the manuscript; Q.J. and W.L. fabricated the thermoelectric and contact materials; K.M. contributed to CSTEG fabrication and experiments and device modelling; F.C. fabricated spectrally selective solar absorbers; L.A.W. contributed to manuscript preparation and CSTEG fabrication and experiments; J.L. contributed to CSTEG fabrication and experiments; Z.R. directed research at UH; G.C. directed research at MIT and contributed to the manuscript preparation.

Corresponding authors

Correspondence to Zhifeng Ren or Gang Chen.

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The authors declare no competing financial interests.

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Supplementary Information

Supplementary Figures 110, Supplementary Tables 1 and 2, Supplementary Methods and Supplementary References (PDF 1841 kb)

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Kraemer, D., Jie, Q., McEnaney, K. et al. Concentrating solar thermoelectric generators with a peak efficiency of 7.4%. Nat Energy 1, 16153 (2016).

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