Solar innovator First Solar has just announced a new word record for solar cell conversion efficiency, for its cadmium-telluride (CdTe) thin film solar cell. That’s significant because CdTe solar cells can be made more quickly and cheaply than conventional silicon solar cells, bringing down the cost of solar power. The title of solar efficiency record holder is also significant politically because it was only last spring that First Solar was caught in the crosshairs, when certain members of Congress tried to manufacture scandals out of the Obama Administration’s support for the U.S. solar industry.
In tests confirmed by the National Renewable Energy Laboratory, First Solar’s CdTe solar cell achieved a conversion efficiency of 18.7 percent.
That’s far less than the efficiency of, say, an advanced concentrated solar system, but the relatively low cost of producing CdTe thin film solar cells makes up for a world of sin. First Solar’s manufacturing process can turn a sheet of glass into a solar module in less than 2-1/2 hours, which according to the company gives it the industry lead in energy payback time.
Thin film technology is also generally lighter and potentially more flexible than conventional solar cells, giving it a broader range of application. The trick is to tease out just a bit more efficiency from the technology to keep it commercially competitive.
First Solar has already been transferring its efficiency improvements into commercial production. Last year, the average efficiency of its production modules went from 12.2 percent to 12.9 percent, with the leading line achieving 13.1 percent.
By way of comparison, other commercial CdTe solar cells range in efficiency from about 10 percent to 12.4 percent.
Silicon is still by far the most-used material in photovoltaics but the Department of Energy has had its eye on CdTe at least since 1994, when NREL started up a public-private R&D partnership called the Thin Film Photovoltaic Partnership Project.
The Thin Film Project focused on three types of promising thin film materials. It included small companies for pilot projects, but for commercial production it assigned one major thin film manufacturing company to each of the three materials.
One of those companies was First Solar, making it the only major CdTe manufacturer that the Thin Film Project has focused on since 2003 (yes, from the early years of the Bush Administration).
The whole point of the Thin Film Project was to help the U.S. solar industry regain its competitive edge in the global solar power market. When the project first started, thin film was an extremely expensive, rarefied technology that was used primarily in space programs. It achieved marvelous results under the Bush Administration. From 2003 to 2008, U.S. thin film manufacturing capacity grew from about 10 MW (megawatts) to more than 250 MW.
– source cleantechnica.com