Case Study

A Sunny Past and Future: Georgia Tech Advances Solar Energy Research

Published: April 3, 2005

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In the mid-70's, the Engineering Experiment Station (now the Georgia Tech Research Institute) operated a solar energy research program with interests in high-temperature solar thermal energy conversion, electric power generation, and liquefaction and gasification of biomass using solar thermal energy.

At the U.S. Department of Energy-funded Solar Thermal Test Facility on the main campus, Georgia Tech Research Institute (GTRI) researchers developed a method for creating high-grade synthetic fuels with solar thermal energy. In 1980, researchers from GTRI and Princeton University announced a breakthrough in pyrolysis in which highly concentrated solar energy, rather than burning of biomass, provided the heat necessary for pyrolysis reactions. Subsequently, GTRI researchers were instrumental in developing standards for several different types of biomass fuels through the American Society for Testing and Materials (ASTM).

GTRI engineers at the Solar Thermal Test Facility directly produced power-grid quality electricity with a Georgia Tech/Swedish-built Stirling external combustion engine, whose pistons were driven by helium heated by intense sunlight.

By the mid-1980s, interest shifted to photovoltaics (PV), as the efficiency of PV devices increased and the cost of making solar cells decreased. A research program in the School of Electrical and Computer Engineering studied new semiconductor materials and designed innovative devices.

In 1992, that work garnered Georgia Tech a Department of Energy contract to operate the University Center of Excellence for Photovoltaics Research and Education.The center, directed by Regents Professor Ajeet Rohatgi, was awarded to Georgia Tech for its sustained contributions to the science and technology of photovoltaics. Its mission is to give the United States a competitive edge in PV through high-quality research and education on PV materials, devices and systems.

Today, the Center operates a 340-kilowatt PV system installed on the Georgia Tech Aquatic Center, which was built for the 1996 Olympics. It produces enough electricity to provide 30 to 40 percent of the building's power needs - an amount sufficient to energize 70 average homes.

The Aquatic Center serves as a test bed for large-scale PV arrays. It continues to provide a wealth of information about the reliability of large PV systems, how they should be connected to the utility grid for effective, distributed generation and what architects should expect from the growing number of similar systems being integrated into new buildings, Rohatgi says. UCEP is conducting research to improve the design, performance and reliability of PV systems.

Work under way in UCEP also produces basic scientific advances and improvements in manufacturing technologies for silicon solar cells. Researchers are working to reduce cell-processing cost without compromising efficiency to make PV-generated electricity more competitive with other sources, Rohatgi explains. Through computer modeling, UCEP has established cost and technology roadmaps for making PV cost-effective. UCEP has produced record-breaking high-efficiency cells on various low-cost, multi-crystalline silicon materials through material-quality enhancement and technology development, he adds.