Double-Reflector Hybrid Solar Energy System

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Des Plaines, Illinois
Project Term:
05/13/2014 - 01/31/2018

Technology Description:

Gas Technology Institute (GTI) is developing a hybrid solar converter that focuses sunlight onto solar cells with a reflective backside mirror. These solar cells convert most visible wavelengths of sunlight to electricity while reflecting the unused wavelengths to heat a stream of flowing particles. The particles are used to store the heat for use immediately or at a later time to drive a turbine and produce electricity. GTI’s design integrates the parabolic trough mirrors, commonly used in CSP plants, into a dual-mirror system that captures the full solar spectrum while storing heat to dispatch electricity when the sun does not shine. Current solar cell technologies capture limited portions of the solar spectrum to generate electricity that must be used immediately. By using back-reflecting gallium arsenide (GaAs) cells, this hybrid converter is able to generate both electricity from specific solar wavelengths and capture the unused light as heat in the flowing particles. The particle-based heat storage system is a departure from standard fluid-based heat storage approaches and could enable much more efficient and higher energy density heat storage. GTI’s converter could be used to provide solar electricity whether or not the sun is shining.

Potential Impact:

If successful, GTI’s hybrid solar converter could simultaneously generate electricity and dispatchable heat even while the sun is not shining.


Developing new systems that perform both of these functions at the same time could provide domestically-sourced power at costs comparable to traditional sources, 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. Rachel Slaybaugh
Project Contact:
Dr. Aleksandr Kozlov
Press and General Inquiries Email:
Project Contact Email:


University of California, Merced

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