When it comes to achieving the highest levels of efficiency for converting sunlight into electrical energy, nothing has ever managed to beat concentrator photovoltaics (CPV). CPV is based on special multi-junction solar cells interacting perfectly with the optical components used in the module. The Fraunhofer Institute for Solar Energy Systems ISE is part of the consortium of research institutes and companies collaborating as part of the EU-funded CPVMatch project to find ways of optimizing both aspects with the aim of harnessing the potential of this technology even more effectively. The module efficiency rating of 41.4 percent achieved as part of this effort is the highest ever recorded for a photovoltaic module.

High-concentration photovoltaic systems (HCPV) technology is intended primarily for use in regions that enjoy high levels of direct sunlight, where it can provide renewable electricity with maximum efficiency and minimum use of resources. Multi-junction solar cells based on III-V compound semiconductors with several very thin subcells stacked on top of one another utilize the solar spectrum far more efficiently. These are combined with optical lenses that concentrate the incoming solar radiation onto the solar cells' miniaturized surface. The modules are mounted on two-axis tracking units to follow the path of the sun. "In CPVMatch, we have addressed all the production steps for concentrator modules, starting from the materials, through cell fabrication and production systems, right up to the challenges faced in manufacturing the modules," explains Dr. Gerald Siefer, project head and group leader of III-V Cell and Module Characterization at Fraunhofer ISE. Dr. Andreas Bett, institute director of Fraunhofer ISE, adds: "Photovoltaics is booming worldwide, and we see great potential for this particularly efficient module technology. It significantly reduces resource consumption for energy conversion per unit area, thus improving sustainability."

Fraunhofer Institute for Solar Energy Systems ISE (79110 Freiburg, Germany)
Website: www.ise.fraunhofer.de/en