Solar Cells Info

Article by Bruce Morey
Source:  Solarforecast.com
http://www.solarforecast.com/ArticleDetails.php?articleID=322

With the on-going shortage of silicon feedstock on the minds of many in the solar PV industry, it is natural to seek an alternative to creating solar cells that use silicon based products. CIGS solar cells, sometimes referred to as CIS, are made from Copper, Indium, Gallium and Selenium and have been under development for some time. Most notably, they do not contain any silicon. If current announced plans are achieved, this technology should be able to deliver solar modules in production quantities in 2007. The steps to production have included manufacturing ramp-up and the work needed for market introduction.
CIGS cells are claimed to be less expensive per Watt installed, more efficient in low-angle and low-light conditions and consume less material overall. They also have the potential to be flexible in their configurations, making them attractive for building integrated PV (BIPV).

CIGS solar cells and modules have achieved conversion efficiencies of 19.5% and 13%, respectively, in a laboratory setting according to a paper published by researchers at the National Renewable Energy Laboratory (NREL) (http://www.nrel.gov/) in Golden, CO. Actual production module efficiencies are expected to be slightly lower than these laboratory results, but still attractive. Manufacturers are targeting production module efficiencies in the 10-12% range.

A number of companies are pursuing a ramp-up of CIGS technologies to production scales.  Most of the companies surveyed in this article are expecting to be in production by 2007 or early 2008.

A key element in the large scale introduction of CIGS is the manufacturing plant. The manufacturing processes are much different from those used in silicon solar cells, making it difficult for the companies introducing CIGS to adapt solar cell manufacturing technology. In addition, different processes are being pursued by individual manufacturers.
Market introduction is being pursued in some cases by encasing the thin-film solar cells in the existing form-factor for standard solar modules. For example, DayStar Technologies will be supplying solar cells to module manufacturers whose module’s form factor is exactly like the current solar modules containing silicon solar cells. Some are pointing out that these modules may be more appropriate for Building Integrated PV (BIPV) because of their black matte finish. For those using flexible substrates, BIPV looms large in their marketing plans because of the flexible form factors possible.

Some of the companies pursuing the CIGS line of development and attempting to ramp-up to full scale production in the next 6 – 18 months are:

Aleo AG (http://www.aleo-solar.com),
DayStar Technologies (http://www.daystartech.com),
Global Solar, Inc (http://www.globalsolar.com),
Honda Motor Company (http://world.honda.com).
MiaSole (http://www.miasole.com ),
Nanosolar, Inc (www.nanosolar.com),
Shell Solar (http://www.shell.com//shellsolar),
Showa Shell Sekikyu (http://www.showa-shell.co.jp/english/index.html), and
Würth GmbH (www.wuerth-solar.com),

Aleo Solar AG has announced plans for access to CIGS thin film solar cells. They secured access to the CIGS technology through license from PTIP, Ltd, a spin-off of the University of Johannesburg, South Africa. Johanna Solar Technology GmbH, a company with shares in PTIP, has announced plans for production. According to an Aleo press release, a production company has been founded for manufacturing of the cells. Production is planned for mid-2007. The capacity of the planned facility will initially be 30 MW and an increase to 60 MW is planned for 2009.  Most of the CIGS cells will be sold under the Aleo brand.

DayStar has been producing limited quantities in pilot production plants, its GEN I and GEN II lines, but expects to ramp-up production in 2007 with its GEN III full scale production line. Terry Schuyler, Vice President of Sales and Marketing for DayStar confirmed that they project an initial production capacity of 10MW in early 2007 and projects a capacity of 20MW by the end of 2007 by replicating the original 10MW line. Once DayStar has reached the most cost-effective production platform (e.g., 25-100MW line) it believes it could then be replicated to achieve Gigawatt or greater size factories. Their TerraFoil FP cells are said to be a lower cost alternative to silicon-based solar cells for use in flat plate rooftop applications, as building materials, or to erect large free-standing solar farms.

Global Solar produces CIGS solar products at the present time for consumer and military applications, where flexibility and high yield are important. These products meet the durability requirements required for camping and military applications. Global Solar is expecting, through its current research and development program, to also meet the more stringent requirements needed for commercial and utility solar PV applications. According to Karen Whitley, Global Solar’s Director of Sales and Marketing, they are expecting to roll-out a production facility by early 2008 that could produce up to 60MW annually of solar PV based on CIGS divided between its traditional consumer and military applications while introducing solar modules for residential, commercial and utility applications.

Honda has announced its intention to start operations in 2007, at a new plant on the grounds of the Kumamoto Factory, where CIGS solar cells will be mass-produced at a rate of 27.5 megawatts annually. Honda Motor Company has installed CIGS thin-film solar cell panels at twelve sites in Japan and three sites outside of Japan.

According to MiaSolé’s President and CEO Dave Pearce, MiaSolé has been developing its own production line for solar cells at its facility in Santa Clara, CA, USA . Each production line is expected to have a production capacity of 25MW and MiaSole expects to have 2 production lines operating by the 4th Quarter of 2006. MiaSole expects to have 8 solar cell production lines operating by the end of 2007 with a total production capacity of 200MW. Their CIGS thin film is on a flexible stainless steel substrate, according to Pearce. The initial market introduction strategy is to sell solar cells to module manufacturers. The initial solar modules will more than likely look like the existing silicon modules, made of glass and aluminum, but will contain MiaSole CIGS solar cells. MiaSole expects to introduce a line of flexible modules of its own design with a targeted introduction for the third quarter of 2007. According to Pearce, “The gating item is not the module or production process but getting it through certification.” MiaSolé is also working with existing module manufacturers and building materials companies that plan on introducing a line of flexible Building Integrated PV (BIPV) modules incorporating MiaSolé’s cells.

NanoSolar has announced its plans to construct a 430MW facility based on CIGS technology. An inquiry regarding the groundbreaking date for plant has not been answered at the time of this writing. In August of 2006 Nanosolar Inc. and Conergy (http://www.conergy.us ) group signed a long-term agreement to develop large-scale photovoltaic systems with tightly interconnected panel and equipment design innovations, according to a press release issued by Conergy.

According to its website, Shell Solar has played a role in the development of first-generation CIGS technology. In early 2006, Shell Solar started working with Saint-Gobain, a producer of glass and other building materials based in France, to explore further development opportunities for the next generation CIGS technology.  Shell divested all of its silicon production to SolarWorld AG to concentrate on CIGS development. Shell is negotiating the construction of a 20 MW plant with St. Gobain for CIGS production. According to Shell Renewables spokesman Jeroen Van Den Berg, “Shell Solar is working hard to set-up manufacturing facilities for the production of CIGS ‘thin-film’products. It is expected that this process will take until early 2008.”

In Japan , Showa Shell Sekiyu announced in a press release on August 11, 2006 that the construction of its CIGS solar module production factory was completed as planned in June. The factory, with annual production capability of 20MW, is expected to start its commercial production at the beginning of 2007.

Würth GmbH of Germany has been developing CIGS solar cells since 1999.  Their first step-up into mainline production will be in 2006. The company plans to have production capabilities of 14.7MW, with a planned start of the production line in the 4 th quarter of 2006.  They advertise producing standard modules, customized modules and semi-transparent modules for use in BIPV.

There may be more CIGS companies in the near future.

There may yet be more CIGS companies to discuss in the near future. According to Harin Ullal, Senior Researcher in CIGS solar PV at the NREL, “There will be a total of 12 to 13 companies entering the market for CIGS solar cells in the next 6 to 8 months. This includes the ones in the market currently and future ones not announced as yet. Many of these are in the early stages of development and have not announced their commercialization plans as yet.”

Shortage of Indium not expected anytime soon.

It has been discussed that Indium may itself be in as short a supply as polycrystalline silicon sometime in the future. Ullal of the NREL says that, “Although there is some discussion of Indium supply being an issue, this will not affect the production of CIGS until there is production capacity in the 20GW range.  This will not happen for some time, and Indium supply should not be a factor in the foreseeable future.”