Photos: With solar energy, it's silicon vs. CIGS

As demand for alternative energy grows, so does the debate over what material is best for solar panels.

By Andy Smith, Contributor Oct. 1, 2006 at 9:00 p.m. PT

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CIGS

CIGS, or copper indium gallium selenide, is being used as the key ingredient in solar panels. Silicon technically is more efficient at harvesting energy from the sun, but CIGS can be printed on flexible sheets. Proponents of the material, such as HelioVolt and Nanosolar, say CIGS can be incorporated into roof tiles and building materials, making the solar technology invisible and the benefits it offers cheap.

In Wales, Shell Solar set up the CIGS-based panels shown in the photo at left. At right, CIGS cells are printed at Nanosolar, a solar-power company based in Palo Alto, Calif.

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Silicon solar panels

What's with the darkened roof tiles? They are silicon solar panels, which can provide up to 65 percent of a home's electricity needs. Earlier this year, California builders began to incorporate them into new homes.

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Home with silicon solar panels

These solar tiles are darker because dark absorbs light better. Grupe Homes has installed these silicon solar tiles on some new homes in a development in Rocklin, Calif.

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