Solar-Concentrating Photovoltaic Mirror

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Tempe, Arizona
Project Term:
06/01/2014 - 08/31/2017

Technology Description:

Arizona State University (ASU) is developing a hybrid solar energy system that modifies a CSP trough design, replacing the curved mirror with solar cells that collect both direct and diffuse rays of a portion of sunlight while reflecting the rest of the direct sunlight to a thermal absorber to generate heat. Electricity from the solar cells can be used immediately while the heat can be stored for later use. Today’s CSP systems offer low overall efficiency because they collect only direct sunlight, or the light that comes in a straight beam from the sun. ASU’s technology could increase the amount of light that can be converted to electricity by collecting diffuse sunlight, or light that has been scattered by the atmosphere, clouds, and off the earth. By integrating curved solar cells into a hybrid trough system, ASU will effectively split the solar spectrum and use each portion of the spectrum in the most efficient way possible. Diffuse and some direct sunlight are converted into electricity in the solar cells, while the unused portion of the direct sunlight is reflected for conversion to heat.

Potential Impact:

If successful, ASU’s hybrid solar energy system could offer a 50% boost in efficiency compared to the efficiency of existing CSP systems by capturing and converting different portions of the solar spectrum using the most suitable approach for each.


Developing new systems that allow storage and dispatch of solar energy provides clean domestic power whether the sun is shining or not.


Replacing energy systems powered by fossil fuels would provide an immediate decrease in greenhouse gas emissions, 40% of which come from electricity generation today.


Cost-effective, dispatchable solar energy alternatives would stabilize electricity rates for consumers as the penetration of renewable energy increases in the coming years.


ARPA-E Program Director:
Dr. Eric Schiff
Project Contact:
Prof. Zachary Holman
Press and General Inquiries Email:
Project Contact Email:


University of Arizona

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