4 April 2011

NREL and AIST to compare CPV cells from USA, Japan and Germany

The US Department of Energy’s National Renewable Energy Laboratory (NREL) in Golden, CO, USA is partnering with international industrial technology and solar research organizations to test how solar cells from three different manufacturers — in the USA, Japan and Germany — perform under different average lighting conditions characteristic of the study’s two test sites in Aurora, CO, USA and Yokohama, Japan.

Concentrator photovoltaic (CPV) solar systems (which use lenses to multiply the sun's intensity, reduce the area of solar cells needed, and improve the efficiency of conventional photovoltaics) have been installed at the test sites partly to measure how well the same cells perform in the high-altitude sunshine of Colorado in comparison with those in cloudier, lower-altitude Japan.

NREL teamed with Japan’s National Institute of Advanced Industrial Science and Technology (AIST) — the largest research organization in industrial science and technology in Japan — to install 25kW of CPV systems at the Solar Technology Acceleration Center (SolarTAC) in Aurora. SolarTAC originated in 2008 when six public and private sector entities — original founding member Xcel Energy, Abengoa Solar, the City of Aurora, the Colorado Renewable Energy Collaboratory, Midwest Research Institute (MRI), and SunEdison — joined forces to establish the USA's largest test facility for solar technologies.

Managed and operated by MRI, SolarTAC provides a venue that supports proprietary research, testing, demonstration and validation by member companies (as well as collaborative activities between members) of a broad range of solar technologies at the early commercial or near-commercial stage of development, at utility scale and under actual field conditions. SolarTAC member NREL plans to host multiple projects there.

CPV systems made by Japanese manufacturer Daido Steel are installed at both the Aurora and Yokohama sites and are designed to compare solar cells made by Spectrolab of the USA, Sharp Corp of Japan, and Azur Space of Germany.

Daido’s CPV design uses a dome-shaped Fresnel lens and concentrator solar cells with efficiencies approaching 40%, resulting in module efficiencies of about 30%. By contrast, most existing PV panels on rooftops have an efficiency of 20% or less. The output of the CPV systems will be compared with conventional silicon PV modules.

The study will also test high-efficiency versions of the gallium indium phosphide/galium arsenide (GaInP/GaAs) solar cells originally invented and developed at NREL, which are now used for space exploration applications such as the Mars rovers. The high efficiencies of these cells, coupled with system designs that greatly reduce the area that needs to be covered by solar cells, have attracted growing interest in recent years, says NREL. In the modules being tested, solar cells cover 1000th of the space covered by similar conventional solar modules.

The project is funded primarily by AIST as a part of the ‘R&D on Innovative Solar Cells’ project, which in turn is funded by Japan’s New Energy and Industrial Technology Development Organization (NEDO, established by the Japanese government in 1980 to develop oil-alternative energy technologies).

Tags: NREL AIST CPV cells

Visit: www.solartac.org

Visit: www.nrel.gov

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