Concentrating solar thermoelectric generators with a peak efficiency of 7.4

• Published in: Nature energy Vol. 1; no. 11
• Main Authors: Kraemer, Daniel, Jie, Qing, McEnaney, Kenneth, Cao, Feng, Liu, Weishu, Weinstein, Lee A., Loomis, James, Ren, Zhifeng, Chen, Gang
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19.09.2016; Nature Publishing Group
• Subjects: 639/4077/4107; 639/4077/909/4101; Economics and Management; Energy; Energy Policy; Energy Storage; Energy Systems; Renewable and Green Energy; SOLAR ENERGY; thermoelectric devices and materials
• ISSN: 2058-7546; 2058-7546
• DOI: 10.1038/nenergy.2016.153

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. Solar thermoelectric generators are a promising technology for converting solar energy into electricity, however their efficiency has been limited to 5.2%. Kraemer  et al. report a solar thermoelectric generator with an efficiency of 9.6%, resulting in 7.4% efficiency in a concentrating solar thermoelectric system.