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Thin-Film Photovoltaic

In July, Southern California Edison installed the first of what will be 250 Mw worth of PV panels located on commercial rooftops throughout the utility’s territory, where power is most in demand. But instead of silicon, the panels were made of a thin film of cadmium telluride, or “cad-tel” for short. Thin-film PV has been touted for years as a cheaper replacement for traditional silicon cells, but past designs have had trouble scaling up to mass production. Cad-tel technology has “completely changed what people thought could be done with thin films,” says Larry Kazmerski, director of the National Center for Photovoltaics at the National Renewable Energy Laboratory in Colorado.

First Solar, the company that made the panels, estimates its manu­facturing cost to be $1.14 per watt and falling, about half the cost of comparable silicon panels. As a result, Kazmerski says, “There’s a big turn happening.” First Solar quadrupled its manufacturing capacity from 2006 to 2007, to 396 Mw, and it expects to exceed 1000 Mw next year. Two years after its initial public offering, the company’s market value is over $20 billion—double that of General Motors.

Cad-tel isn’t the only promising thin-film technology on the market. Newer panels developed using a copper indium gallium selenide (CIGS) semiconductor have efficiency ratings almost 30 percent higher than First Solar’s cad-tel PVs. The advances have sparked a flurry of startup companies. Venture capitalists are pouring in 20 to 100 times more money than government research funds are, Kazmerski says, creating what some are calling a dot.sun phenomenon.

California-based Nanosolar is among the companies racing to commercialize CIGS technology. But like First Solar, most of its sales have gone to European countries such as Germany and Spain, where long-established policies provide a stable, guaranteed price for solar power production. Here in the U.S., uncertainty looms about a 30 percent investment tax credit that is set to expire at the end of the year. For billion-dollar projects such as Abengoa’s Solana plant, extension of the tax credit is make-or-break: These projects simply won’t happen without an extension of at least eight years.

Ultimately, solar power will have to justify (and pay for) itself—and the market may be moving in that direction. The DOE predicts that solar electricity will be cheaper than the average grid price by 2015. What’s more, prices for natural gas have doubled in the past five years, coal has nearly tripled, and new nuclear plants won’t come on line for at least seven more years. Locking in a long-term contract with a solar plant whose fuel will never run out, on the other hand, is the very definition of energy security. “One thing we know about the sun,” Morse says, “is that the price never goes up.”

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