3 October 2012

German Environmental Award for Fraunhofer ISE’s Bett and Soitec’s Lerchenmüller

Dr Andreas Bett, deputy director of the Fraunhofer Institute for Solar Energy Systems ISE, and Hansjörg Lerchenmüller, CEO of Soitec Solar (a division of Soitec of Bernin, France) – both based in Freiburg, Germany - have been named as recipients of the German Environmental Award 2012 for their achievements in research and industry related to concentrator photovoltaic (CPV) technology. Originally developed by Fraunhofer ISE, the CPV technology was brought to market by Soitec Solar.

Awarded each October by the Osnabrück-based Deutsche Bundesstiftung Umwelt (DBU) foundation, the €500,000 German Environmental Award (the highest-value environmental prize in Europe) will be presented this year by the German President Joachim Gauck on 28 October in Leipzig. Entrepreneur Günther Cramer, co-founder & supervisory board chairman of SMA Solar Technology AG of Kassel, Germany, shares this year’s prize with Bett and Lerchenmülle. “With their pioneering technological developments and personal commitment,” the prizewinners have “set worldwide standards in photovoltaics and thus significantly advanced the field at a global level,” comments DBU secretary general Dr Fritz Brickwedde.

For many years now, research and industry have been working on solar energy systems and components, making them increasingly efficient and hence more competitive on the market. Aside from the conventional silicon solar cell technology, a variety of other cell technologies suitable for specific applications have been brought to the market. These include concentrator photovoltaic (CPV) technology, in which a Fresnel lens in each module concentrates the sunlight by a factor of 500 onto small (3mm-wide), high-efficiency multi-junction semiconductor solar cells. With modules with a two-axis tracking system that follows the path of sun, almost twice the incident sunlight can be converted into electricity compared to conventional silicon technology. Concentrator power plants have a modular construction and are hence freely scalable. CPV technology is therefore particularly targeted at use in large power plants ranging from a few to several hundred megawatts in regions with a large amount of direct solar irradiation. Currently, in sun-rich regions of the world such as South Africa or the USA, thousands of industrially produced CPV modules are therefore being used in large power plants.

Fraunhofer ISE’s Andreas Bett and Soitec Solar’s Hansjörg Lerchenmüller.

“A cost-effective optical lens concentrates the sunlight and allows the economical use of the comparative costly semiconductors used in this system,” says Dr Andreas Bett, division director ‘Materials – Solar Cells and Technology’ and deputy director of Fraunhofer ISE (which, with 1200 staff, is Europe’s largest solar energy research institute). “Depending on the concentration factor, only one five-hundredth to one-thousandth of the semiconductor material is required, yet still improving the efficiency of the solar cell,” he adds.

Decisive for the efficient and economical operation of large CPV power plants is the interplay between components, as emphasized by both award winners from Freiburg. This plays a role in module construction, the connection of the modules as well as for the entire system technology and process control. “The efficiency of a concentrator module manufactured by Soitec Solar is currently about 30%,” says Hansjörg Lerchenmüller, general manager of Soitec Solar GmbH in Freiburg. “At the same time, we are using cost-effective materials,” he adds. “Exactly this combination of low material costs and high efficiency is the key to keeping electricity production costs down.” In 2009, Andreas Bett and his team achieved record efficiency of 41.1% for a III-V multi-junction solar cell under laboratory conditions. Both Bett and Lerchenmüller see further potential for increasing the efficiency of solar cells and modules in the future.

At Fraunhofer ISE, in a research team with more than 50 scientists, Bett is working to increase the efficiency of multi-junction solar cells. In the Concentrator Technology & Evaluation Center (ConTEC) they also work on optimizing the construction of the CPV module. Soitec is working on expanding the installed capacity of CPV power plants worldwide. With Soitec’s Freiburg subsidiary Soitec Solar GmbH, Lerchenmüller has contributed to the industrial implementation, commercialization and international expansion of the concentrator technology. The firm transferred the concept of the CPV module to industry. Soitec Solar has also established a 70MWp automated production line for CPV modules in Freiburg. In addition, a module factory with 280MWp production capacity is currently being constructed in San Diego, CA, USA.

“Andreas Bett and Hansjörg Lerchenmüller were key contributors to develop this very innovative, reliable and efficient CPV technology,” says Gaetan Borgers, executive VP of Soitec’s Solar Energy Division. “Today, Soitec operates in Freiburg one of the world’s most modern production lines for manufacturing CPV modules. We already have more than 10MWp installed around the world,” he adds.

Fraunhofer ISE director professor Eicke R. Weber comments that the German Environmental Award “sends a clear signal and emphasizes the significance that innovations in photovoltaics have for the future global energy supply”.

Tags: Fraunhofer ISE Soitec Solar CPV

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