Photovoltaic production in the CIGSfab: integrated factories provide competitive solar electricity

In the face of increased competition on the international solar markets, efficiency and costs count first and foremost. Against the backdrop of changes to and a downward trend in solar funding, the globally competing manufacturers of components are under intense pressure.

On the path to the economic competitiveness of photovoltaics in old and new markets, it is essential to further reduce the production costs of solar electricity. The central approaches to achieving this are a higher level of efficiency of the solar modules and lower production costs along the entire value-creation chain.

A look inside the CIGS innovation line of Manz AG in Schwäbisch Hall. Photo: Manz AG
A look inside the CIGS innovation line of Manz AG in Schwäbisch Hall. Photo: Manz AG

Focus on increased efficiency and lower costs

To ensure future growth and grid parity with fossil and nuclear electricity, every potential can and must be exhausted. One particularly promising technology in terms of increasing efficiency while simultaneously reducing costs comes in the form of photovoltaic modules on the basis of copper indium gallium selenide (CIGS). Formerly a niche market, in recent years CIGS has grown to become an established technology and is quickly gaining ground on the widely used silicium photovoltaics, both in terms of the level of efficiency and costs, as well as the market share.

The market share of thin-film photovoltaics will continue to grow according to market researchers like EuPD Research. CIGS will see the most significant growth. Graphic: EuPD Research
The market share of thin-film photovoltaics will continue to grow according to market researchers like EuPD Research. CIGS will see the most significant growth. Graphic: EuPD Research

Efficiency record in the laboratory and in mass production

In the laboratory, CIGS cells are already achieving an efficiency rate of around 20 percent, and have thus made inroads into the efficiency area of common crystalline photovoltaics. And at 14 percent, a new world record was set in 2011 for module efficiency in series production.

Growth in efficiency of competitors’ thin-film technologies in the laboratory. The current world record is held by the Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW) at 20.3%.
Growth in efficiency of competitors’ thin-film technologies in the laboratory. The current world record is held by the Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW) at 20.3%.

In terms of possible cost reductions – from material use to industrial mass production – CIGS technology opens up enormous potential for a new growth market. One example of integrated production for increasing efficiency and operational capacity while reducing material use and overall operating costs is the CIGSfab from the system manufacturer Manz AG (Reutlingen), which SolarServer named “Solar energy system of the month” in February 2012.

Schematic drawing of the Manz CIGSfab10: from the glass substrate (input in the foreground) to the finished module (output right) the production line brings together all processing steps. (Source: Manz AG)
Schematic drawing of the Manz CIGSfab10: from the glass substrate (input in the foreground) to the finished module (output right) the production line brings together all processing steps. (Source: Manz AG)

CIGS is not new technology. Research began more than 35 years ago at the Institute for Physical Electronics (IPE) at Stuttgart University, the predecessor of the development partner of Würth Solar and Manz, the ZSW. The first pilot production line was running as early as 1975, the second began in 2000 at Würth Solar. The thin-film technology was developed in the laboratory of the Zentrum für Sonnenenergie- und Wasserstoff-Forschung (ZSW). SolarServer named it “Solar energy system of the month” in July 2000: CIS solar cells from the production line: pilot factory for thin-film modules begins operations.

CIGS solar modules in an open-space plant in Spain; systems integrated in the buildings in Ulm (Germany) and Peking (China).
CIGS solar modules in an open-space plant in Spain; systems integrated in the buildings in Ulm (Germany) and Peking (China).

From the laboratory to mass production to an integrated module factory on an industrial scale

Würth Solar embarked on mass production in 2006 with the “CISfab” in Schwäbisch Hall. On January 1, 2012, the high-tech machine manufacturer Manz took on the production line for CIGS solar modules and began to upgrade it to an innovation line. The licenses and the knowledge of Würth Solar were transferred to Manz AG along with the expertise from the research cooperation with the ZSW, which, at 20.3%, holds the world record for efficiency among all thin-film technologies. The aim of Manz AG, which now has the world’s largest R&D team since it took on the 118 Würth Solar employees, is to press ahead with research and development even faster than previously in order to achieve a reduction in production costs and a further increase in the efficiency of the modules.

 

Higher solar electricity yields with competitive technology

Even under difficult conditions, the CIGS modules achieve a high efficiency rate, especially at high ambient temperatures. Furthermore, the modules absorb the sunlight better than silicon modules. This means increased solar electricity yields when there is unfavorable sunshine during the morning or evening hours, as would be the case on a module with an East–West orientation.

Structure of a CIGS solar cell. Source: Manz AG
Structure of a CIGS solar cell. Source: Manz AG

Last year, Manz underscored the huge potential of the CIGS technology in industrial production with another world record. At the EU PVSEC in Hamburg, it presented a module with an efficiency rate of 15.1% on the aperture surface, giving the module an outstanding efficiency rate of 14%.

Numerous reference plants around the world attest to the reliability and efficiency of the CIGS modules in various climate zones. And solar parks with Würth technology that have been financed by leading banks make it easier to finance further projects.

 

Lower costs …

Fully automated, integrated production lines open up considerable potential for reducing costs through standardized equipment, shorter production cycles for the absorber coating, larger substrates, and the integration of glass processing.

Above all, the material costs and the write-downs on the plants constitute almost 80% of the production costs. This is where the CIGSfab comes in: the glass substrate, which should be thinner, along with more cost-effective coating materials. Because, until now, the substrate and coating have been the central factor, accounting for 75% of the material costs.

Since 2010, as a specialist and one of the world’s leading plant manufacturers, Manz was able to reduce capital expenditure (CapEx) for the CIGSfab by around one fifth, and the costs for producing the modules by 25 percent.

CIGS module production line at Manz AG in Schwäbisch Hall
final inspection. Photos: Manz AG

… and higher efficiency

The combination of reduced production costs and increased efficiency is a crucial step towards the competitiveness of photovoltaics and solar electricity production costs.

The increased efficiency of the CIGS modules from 10% to 14% has already reduced costs by almost 30% – and the technology road map drawn up by Manz envisages that efficiency will rise to 15.9% by 2017.

Source: Manz AG
Source: Manz AG

Technology of the future available now

To guarantee success with regard to costs and efficiency, Manz offers customized solutions for the entire CIGSfab. Accordingly, the company asserts that the CIGSfab, which is available with production capacity from 43 Megawatts peak to almost 354 MWp, is the only integrated, turnkey production line for CIGS modules that can already be operated on a profitable basis. In addition, an output guarantee and technology updates provide the necessary investment security.

CIGS production line at Manz AG: the CIGSfab is scalable up to a production capacity of almost 354 MWp. Photo: Manz AG
CIGS production line at Manz AG: the CIGSfab is scalable up to a production capacity of almost 354 MWp. Photo: Manz AG