Solar Cells Info

Source:  Green Energy News
April 17, 2007 – Vol.12 No.4
http://www.green-energy-news.com/arch/nrgs2007/20070051.html

Honda is developing them, so is Shell in its venture it calls Avancis. Less familiar names are also working on what could be the next generation of solar cells and thus solar products: DayStar Technologies, HelioVolt, Nanosolar, W¸rth Solar and Odersun.   Those next-gen cells, CIS (Copper Indium Selenide), and their close cousins CIGS (Copper Indium Gallium Diselenide), offer solar-to-electric conversion efficiencies about the same as silicon solar (efficiencies in the mid to high teens) but conceivably could be offered at a much lower cost.

The reason? CIS and CIGS are very thin, thin-film solar technologies, a 100th or thinner than traditional silicon. Very thin equates to very little material is needed to make them: The less material, the less cost. Yet the commercialization of CIS and CIGS technologies has been slowed by adequate high speed production methods. CIS and CIGS cells are difficult to make. Difficult to produce means high costs despite the lower cost of materials.

Now, however with two companies in Germany, the race for low cost, CIS thin film solar mass production may have begun. Wirth Solar announced in late March that its CISfab solar factory in Schw”bisch Hall is up to full scale production, churning out 500 finished CIS modules per day. And the company plans to double its current 15 megawatt per year capacity by 2008. Its production technology is to apply CIS layers directly to glass substrate. The company now employs 145.

Odersun AG, of Frankfurt, Germany is about to go into commercial production of CIS solar technology. With the opening of its Sun One plant in Frankfurt, nearly endless ribbons of CIS solar photovoltaic material will be produced in a roll-to-roll process.  Those ribbons are CIS layers applied to a one-centimeter wide copper foil backing. The ribbons or tapes are about 100 microns thick, a little thicker than an average human hair. The ribbons can then be cut to any length to be used in solar power products.

The company says it will be able to produce 6000 kilometers of its CIS on copper tape product per year at current capacity; enough to stretch from Germany to New York. (Doing a little math. this works out to about 646,000 square feet or 60,000 square meters of solar electric material).  Solar to electric conversion efficiency is about 10 percent, a little less than conventional silicon solar, but efficiencies are less important as costs drop.

Aside from the potential cost savings of Odersun’s CIS thin film solar, thin also means flexible. Flexible means a wider variety of applications. The ribbons can be laid side by side in strips to make any sized solar product.

The company will begin making small flexible solar panels that could be applied to a women’s handbag or perhaps a backpack for portable solar power, as well as conventionally-sized solar panels for use on roofs or ground-mounted solar powerplants. Other possibilities include solar window shades and awnings. Only one production process is needed to make a variety of solar products. The company will have up to 60 employees working around the clock to keep the roll to roll production rolling, as it were.