A Cheaper Route to Solar Cells

 
1366 Technologies A “direct wafer” from 1366 Technologies, left, made by casting it in its final form, and a traditional one, made by sawing slices off a block. The direct one costs 80 percent less, the company says.

A company that secured a Department of Energy grant to pursue a breakthrough idea in the manufacture of solar cells plans to announce on Tuesday that it has raised $20 million to commercialize its technique, which it says will reduce the price of solar panels by 40 percent.

The company, 1366 Technologies of Lexington, Mass., has found a simpler way to produce the basic building block of solar cells: silicon wafers. It uses molten silicon to cast the wafers in their final form, six inches on one side and 200 microns thick, or about eight-thousandths of an inch.

The current method is to cast the silicon in huge ingots or grow it in giant crystals and then saw off thin pieces, which wastes about half of the silicon.

“Early indications show this could be one of our great success stories,” said David Danielson, the program director for solar energy at the Advanced Research Projects Agency — Energy, a new office within the Energy Department that provides relatively small grants to develop high-risk but potentially high-payoff technologies. It promised 1366 a grant of $4 million for an 18-month program to develop the wafer technology; 1366 is reporting success after eight months.

The company is expected to announce that it has raised $20 million in new capital, some of it from a major customer for the wafers, Hanwha Chemical of South Korea. Other investors include Ventizz Capital Fund, a European company that specializes in clean energy investments. Two companies that had previously invested, North Bridge Venture Partners and Polaris Venture Partners, have also added funds.

The chairman of Hanwha, Ki-joon Hong, said in a statement that his company had “every confidence that 1366’s innovations will fundamentally change solar manufacturing.”

The silicon, the basic material of solar cells and computer chips, is derived from a very cheap material, sand. But to function in electronics it must be made extremely pure, which makes it expensive.

The new technique, going from molten silicon to final product, is a bit like frying pancakes as opposed to slicing salami, except, as Mr. Danielson put it, “when you cut a salami, it’s not like half the salami ends up as salami dust that you have to throw in the garbage.”

The trick is to get the wafer out of the mold without breaking it. Company officials will not say just how they do that. The president of 1366 Technologies, Frank van Mierlo, predicted that the development would make solar power cheaper than coal power, although the technique has not yet been commercialized.

If the wafers go to market, 1366 would be one of the early fruits of the ARPA-e program, which was authorized by Congress in 1997 and signed into law by President Bush but was not financed until the passage of the federal stimulus act, which gave the program $400 million over two years. In December, 1366 received $4 million.

The company’s name is a reference to the amount of solar energy, measured in watts, that falls on a square meter of the earth’s surface.

The cell has other refinements, including finer wires to conduct away the electrons, so the shadow cast on the energy-gathering area is smaller. And the company drills small holes into the cast wafer to give it a honeycomb appearance, which allows light to bounce around inside the crevices, producing better absorption and less reduction, Mr. van Mierlo said.

By MATTHEW L. WALD/NYT

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