Germany, France join forces to achieve new record in solar CPV efficiency

Researchers from Europe’s largest solar research institute have announced a world record in module efficiency of 36.7 per cent – the best value ever achieved for a concentrator photovoltaic module (CPV).

A team at the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany, have been developing concentrator photovoltaic (CPV) module technology, known as FLATCON (pictured below), for years, using fresnel lenses to bundle sunlight and focus it onto miniature, highly efficient solar cells.

The new record in efficiency, announced on Monday, was achieved by adapting the concentrating lens to a new wafer bonding solar cell structure, developed in conjunction with French CPV developer, Soitec, over the past decade.

Soitec’s four-junction solar cell, implemented into the Fraunhofer ISE module concept, meant sunlight was concentrated by a factor of 230 suns onto fifty-two 7 mm2 miniature solar cells, with the help of fifty-two 16 cm2 Fresnel lenses.

“Naturally we are incredibly excited about this high module efficiency,” said Dr Andreas Bett, who leads the CPV research at Fraunhofer ISE and has received various awards for his work, including the German Environmental Award 2012.

The result, says Dr Bett, shows that the high efficiencies of Soitec’s novel four-junction solar cells can be transferred to the module level.

Concentrator photovoltaic systems (CPV) are installed in sun-rich regions, where such systems produce solar electricity for less than 8 eurocents per kilowatt-hour.

The key to the technology is the solar cell efficiency and the concentrating optic. In the record module, the newly developed four-junction solar cell was combined with Fresnel lenses, which were manufactured by the industry partner ORAFOL Fresnel Optics based on a new Fraunhofer design.

The successful transfer of this high module efficiency to commercially manufactured modules is expected within one to two years.