CSU physics professor speaks at world’s largest photovoltaic conference

Jim Sites And Mechanical Engineering Professor Walajabad SampathSince stepping down from his role as associate dean for research in the College of Natural Sciences this August, Jim Sites, has been busy promoting Colorado State University’s solar energy innovations around the world.

In the past four months, the professor in the Department of Physics has spoken at several international conferences on photovoltaics, or PV – the basis for solar panels that convert sunlight into electricity. In September, Sites delivered a plenary lecture to more than a thousand people at the European Union Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC), the world’s largest photovoltaic conference, held this year in Amsterdam. The conference has hosted discussions among solar energy experts working in research, development and private industry for more than 30 years.

In his lecture, Sites provided an overview of American developments in PV, including CSU’s work in solar panel research. In particular, he discussed using cadmium telluride (CdTe), a semiconductor layer that converts solar light into electricity as efficiently and less expensively than traditional materials.

Sites said that CSU has for many years explored using cadmium telluride in thin-film solar panels that have thin layers of CdTe and contacting materials between large sheets of glass. This approach has received less attention in Europe than the U.S., but according to Sites, the recent CdTe innovations here received very positive feedback from the European attendees.

“I think there was some genuine interest in what has been developing in the U.S.,” he said.

Sites has been able to attend conferences he might have passed up when he was working in the dean’s office. In addition to three conferences in Europe and one in Japan, Sites helped organize a cadmium telluride workshop in China in August and another in Santa Clara, California, in November.

Jim Sites in Amsterdam talking about CSU's developments in solar panel technologiesSpotlight on sunlight

Sites leads CSU’s Photovoltaics Laboratory in Physics, a research lab that studies solar cells and panels made with CdTe and other thin-film materials. Sites works closely with Walajabad Sampath a professor in the Department of Mechanical Engineering who leads the CSU site of the Next Generation Photovoltaics Center, a National Science Foundation (NSF) Industry/University Cooperative Research Center (I/UCRC). The center is a collaboration between the NSF, five universities including CSU, and solar power companies in the U.S. and abroad. Its vision is making PV electricity a major source of the world’s energy.

“[At CSU] We’re very conscious that our results will be much more useful if they can be tied to a manufacturing process,” Sites said. “We would like to do things which, at least in principle, can be manufactured on a large scale.”

Solar energy is expanding throughout the U.S., but it still makes up only 2 percent of the total electricity generated. However, two years ago that number was only 1 percent, Sites said, and it’s bound to continue growing rapidly.

In response to this growth, Sites said that the current electrical grid will have to incorporate more energy- storage technologies to account for the lack of solar power at night. Storage methods include batteries, pumping water uphill and using the downhill flow to run turbines, or compressing air into caves, also to later drive turbines.

“The emphasis is shifting from the basic panels to the overall power-generation and distribution system,” he said.

In addition to solar power for homes and businesses, Sites sees a very large increase in electric cars that are recharged using renewable energy sources.

Throughout his career, Sites has published more than 160 scientific papers, advised more than 30 doctoral students, and taught most of the physics courses offered at CSU. He has also attended and lectured numerous times at PV conferences throughout the U.S., Europe, and Asia.