New solar CIGS cells creep up on silicon

By Matt Daily

NEW YORK (Reuters) - Silicon cells have been the mainstay of the solar photovoltaic industry, but advances in competing technologies could give those manufacturers a toehold in the rapidly growing renewable power market.

Last week, researchers at the U.S. Department of Energy's National Renewable Energy Laboratory said they had achieved a new efficiency record for one of those promising technologies, putting it within reach of the silicon cell mark.

The new technology uses copper indium gallium selenide, or CIGS, to turn sunlight into electricity inside a thin-film solar cell that is generally less expensive than versions relying on polysilicon.

CIGS technology converts 19.9 percent of the sunlight hitting the cell into power, beating the previous mark of 19.5 percent and nearing the multicrystaline silicon cell record of 20.3 percent.

Although the increase in efficiency looks modest, it would represent a 3 percent rise in production capacity for a company putting out one megawatt of electricity per year, said Ingrid Repins, a researcher on the NREL team. One megawatt can power about 850 homes.

Silicon-based solar cells held 94 percent of the global market in 2006, according NREL data, with the remaining 6 percent split among thin-film companies, including CIGS makers.

But that thin-film market share appears to be growing rapidly, helped by the opening of plants by companies such as First Solar, which uses different materials to construct its cells.

Just a few years ago, CIGS cells' efficiency stood near 15 percent, Repins said, and the technology is probably capable of reaching 23 percent in coming years.