The MIT Technology Review published today an interesting article about Twin Creeks Technologies, a startup company that has an invention that they claim halves the cost of silicon solar cells.
The company's CEO Siva Sivaram has had a pilot plant built in Mississippi. Less silicon is needed and the manufacturing equipment is cheaper. He claims that the company can produce solar cells for about 40 cents per watt, half the present cheapest price. The company has raised $93 million in venture capital.
The usual way to make silicon wafers is cutting blocks of silicon into 200-micrometer-thick wafers. This means that half the silicon is wasted. This thickness is used not because it is needed to produce the power, but because thinner wafers are too brittle and would easily break in the manufacturing process. A thickness of 20 or 30 micrometers would work as well.
Twin Creeks' technology consists of applying a thin layer of metal to the silicon, using a huge machine illustrated in the article. The use of wire saws and other equipment is also reduced. Crucially, perhaps, the technology can be added to existing production lines. The company wants to sell the equipment, not make solar cells.
What is particularly interesting about the article is that is describes the company as "a startup that has been operating in secret until today". Not that secret, I think -- their World patent application Method to form a photovoltaic cell comprising a thin lamina was published in August 2009.
Thanks to my colleague Peter Gibbs who drew my attention to the article.
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