Thin-Film Solar Research and Testing at DOE's ORNL

On the roof of the largest research building along the courtyard of Oak Ridge National Laboratory's new east campus, perches a 700-watt solar system. The combination of concentrating solar modules and a turntable tracker makes the photovoltaic system more efficient and less costly than conventional systems. In each module 24 reflectors focus sunlight onto 72 single-crystal silicon solar cells. The four 175-watt modules concentrate sunlight up to three times its normal strength, reducing by two-thirds the number of expensive silicon cells required to produce the same amount of electricity.

Solar Tracker

An inexpensive solar tracker keeps the modules facing the sun throughout the day, theoretically increasing the energy output as much as 35% in some regions. ORNL purchased and installed the system in September 2007. 

Hybrid Solar Lighting

The rooms at the top of a nearby four-story research building are illuminated by hybrid solar lighting. In this technology pioneered by ORNL, sunlight is piped into rooms through optical fibers, and intelligent sensors adjust artificial light levels needed by occupants during cloudy days.

Sunlight Direct of Oak Ridge is commercializing this technology, which has entered the demonstration phase with installed systems at locations owned by Wal-Mart, Staples, Battelle and San Diego State University.

Thin-Film Solar Cells

ORNL materials researchers using the plasma arc lamp hope to demonstrate elimination of defects from multicrystalline and amorphous silicon thin-film solar cells, which are less efficient than single-crystal solar cells but less expensive to make. Measurements of these processed materials will be made at the new Center for Advanced Thin-film Solar Cells. (See Research Horizons: A Renewed Interest)

The Department of Energy, is a major driver behind ORNL's expanded research in solar energy. Craig Cornelius, acting program manager of Solar Energy Technologies in DOE's Office of Energy Efficiency and Renewable Energy, has indicated that greater funding for research to make solar materials more efficient and less expensive will be available to national laboratories.

ORNL, which boasts one of the world's leading materials research capabilities, proposes innovative basic technology research to help meet DOE solar materials challenges.

ORNL plans to install more photovoltaic panels, perhaps as solar walkways and solar roofs over parking lots, and possibly biomassfired boilers, to help achieve that goal.

Cornelius, who leads the Solar America Initiative as part of the President's Advanced Energy Initiative, has stated that DOE's goal is to make solar energy cost-competitive with conventional forms of electricity by 2015. DOE predicts that by 2015, solar energy will produce 15 gigawatts, enough to power 11.2 million American homes.

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