Pluto: Suntech's Shot at Technical Glory

The Chinese giant has a new, efficient solar cell that will let it better compete against the high-efficiency guys like SunPower.

Suntech Power Holdings is moving on up.

The Wuxi, China-based manufacturer of solar panels – which says it is No. 1 in volume – is making a concerted push into the high-efficiency market with Pluto.

In labs, a Pluto cell has achieved an efficiency of approximately 25 percent, said Steve Chadima, vice president of external affairs in a talk at the ThinkGreen conference in San Francisco. That's a world record for crystalline silicon solar cells, he said. It also approaches the 29 percent theoretical maximum for silicon cells.

But Pluto is also in mass manufacturing. Monocrystalline Pluto cells off the line are achieving close to 19 percent efficiency while multicrystalline cells are achieving just over 17 percent.

These kinds of numbers allow Suntech to start competing more directly at the high-end of the market with SunPower, long the leader in high-efficiency cells. SunPower makes cells with 22 percent plus efficiency and pops out solar panels with 18 percent to 19 percent efficiency with astonishing regularity. (Cells have a higher efficiency rating than entire modules.)

Suntech's standard commercial cells are in the mid- to low-high teens in terms of efficiencies, and module efficiency is a few points lower. Thus, a gap exists, but it is narrowing. Higher efficiency cells, of course, sell for more.

The company already has capacity to make 30 megawatts of Pluto cells a year and will expand to 100 megawatts this year, Chadima said. The goal is to sell 50 megawatts this year.

Pluto is based on the PERL technology from the University of New South Wales in Australia, where Suntech founder Zhengrong Shi taught for years. The technology essentially involves texturing layers inside the cell to better trap light. Suntech also uses thin metal lines to reduce shading.


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