Cost > CIGS: A Bright Future?

Solar panels made from Copper Indium Gallium Selenide (CIGS), a potentially cost-effective alternative to silicon-based cells, are gaining momentum. A main driving force behind increased investment and interest in CIGS technology is the continuing shortage of polysilicon, the main feedstock for conventional PV panels. The other is that, once production is ramped up, CIGS-based cells have the potential for considerable cost savings over their silicon-based counterparts.

“CIGS” refers to the type of semiconductor used, which is 100 times thinner than a silicon semiconductor. Though the materials are relatively standard, manufacturing processes differ greatly: some companies electroplate or sputter the semiconductor onto a substrate, or immerse the substrate in a solution of the semiconductor and evaporate the excess. Because the substrates are variable (added to plastic, glass, foil, or even cement) CIGS cells will be more versatile for installation, could be better integrated with buildings at construction, and should be easier to produce than silicon-based cells.

It’s important to note that, compared to silicon-based technology, CIGS cells have low efficiency rates: 8 to 10 percent, compared to 15 to 22 percent solar energy conversion. However, because silicon prices remain fairly high, CIGS is touted as a low-cost contender, despite concerns over efficiency and the availability of indium, a critical component that is also used in the LCD-panel market.

Indium is about as naturally abundant as silver, but silicon provides a perfect example of an element which is not naturally scarce but whose use suddenly skyrocketed with the rise of the solar energy market – causing scarcity lasting several years. Critics worry that indium will follow in silicon’s footsteps if demand suddenly spikes. But proponents of the technology claim that the greater efficiency and recycle rates will prevent such a shortage.

CIGS manufacturers face additional challenges. Because silicon is a well-researched material with well-established manufacturing processes, getting the necessary groundswell of support for a novel material and process like CIGS is difficult. Delays in the development cycle weaken its image, and CIGS may end up in a race to see if it can bring its production volume and efficiency up to acceptable levels before silicon prices drop to the point at which CIGS loses the “cheap-kid-in-town” reputation, which has thus far bolstered its support.

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