A device similar to the giant atom smashers used by physicists may be the key to cheaper solar cells.
Twin Creeks Technologies in San Jose has created a machine that uses high-energy protons to carve silicon wafers into thin layers, each of which can then be fashioned into a solar cell.
The layers are about one-tenth as thick as the standard silicon solar cell but generate just as much electricity. The same amount of raw silicon, therefore, can yield far more cells, making each one less expensive to produce.
Founded in 2008, Twin Creeks exits stealth mode today with $93 million in venture capital, a unique product and a focused business plan.
Unlike other solar startups with new manufacturing techniques, Twin Creeks has no interest in producing its own cells, modules and panels. Instead, it will build its proton-firing machine and sell the device to any solar company that wants it.
"We're not a panel or a cell maker - we make big machines," said Chief Executive Officer Siva Sivaram. "Once one of them uses this, the cost advantage is going to be so large that everybody will be forced to use the same technology."
That technology also could pose a serious threat to thin-film solar companies, many of which are already struggling.
Thin-film companies produce slender, flexible solar cells typically made from materials other than silicon. They're relatively cheap to produce, but they're less efficient than standard silicon cells, generating less electricity per square inch. And as new factories in China have flooded the market with inexpensive silicon cells in recent years, thin-film companies have seen their price advantage disappear.
Silicon cells made with Twin Creeks' technology are so narrow that they can bend and flex just like thin film. And they are as efficient as standard silicon cells, Sivaram said, converting as much as 20 percent of the solar energy that falls on them into electricity. Modules from America's leading thin-film company, First Solar, have an average efficiency of 12 percent.
"If this is 16 percent, 17 percent, 18 percent, and it costs less, why would you go with thin film?" said Eric Wesoff, a senior analyst at GTM Research.
The Twin Creeks machine, dubbed Hyperion 3, operates as a particle accelerator, similar to but much smaller than the machines that physicists employ to study the subatomic world.
It energizes protons with 1.2 million volts of electricity and fires them into silicon wafers. At that energy level, the protons penetrate to a uniform depth of 20 microns - with each micron representing one-millionth of a meter - and form tiny bubbles of hydrogen. The wafer is then heated to 600 degrees Celsius, and a layer of silicon 20 microns deep pops off the wafer. The process, called proton-induced exfoliation, is repeated until all the silicon in the wafer has been used.
The standard process for carving up silicon for cells uses wire saws made of steel, yielding layers 200 microns thick. Roughly half the silicon is wasted in the carving process, Sivaram said.
"The way wafers are made is still like 18th century technology," he said.
The Hyperion machine reduces by about 90 percent the amount of silicon that cell manufacturers need and cuts production costs by roughly 50 percent, according to Twin Creeks. Those savings would give Twin Creeks customers a big edge in a business that has become increasingly cutthroat, a business in which rapidly falling prices have already triggered such high-profile bankruptcies as Solyndra's.
Sivaram won't reveal an exact price but said each Hyperion machine will cost "several million dollars." Each will be capable of producing enough silicon layers to make 1.5 million cells per year. Although the company is headquartered in San Jose, the machines will be assembled and tested at Twin Creeks facilities in Mississippi and Massachusetts.
The company has not yet sold any of the machines but is in discussions with several companies in the United States and China.
SOURCE: http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2012/03/13/BUHU1NINMA.DTL
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| Twin Creeks says its device will produce enough silicon |
| layers to make 1.5 million solar cells a year. |
Twin Creeks Technologies in San Jose has created a machine that uses high-energy protons to carve silicon wafers into thin layers, each of which can then be fashioned into a solar cell.
The layers are about one-tenth as thick as the standard silicon solar cell but generate just as much electricity. The same amount of raw silicon, therefore, can yield far more cells, making each one less expensive to produce.
Founded in 2008, Twin Creeks exits stealth mode today with $93 million in venture capital, a unique product and a focused business plan.
Unlike other solar startups with new manufacturing techniques, Twin Creeks has no interest in producing its own cells, modules and panels. Instead, it will build its proton-firing machine and sell the device to any solar company that wants it.
"We're not a panel or a cell maker - we make big machines," said Chief Executive Officer Siva Sivaram. "Once one of them uses this, the cost advantage is going to be so large that everybody will be forced to use the same technology."
That technology also could pose a serious threat to thin-film solar companies, many of which are already struggling.
Thin-film companies produce slender, flexible solar cells typically made from materials other than silicon. They're relatively cheap to produce, but they're less efficient than standard silicon cells, generating less electricity per square inch. And as new factories in China have flooded the market with inexpensive silicon cells in recent years, thin-film companies have seen their price advantage disappear.
Silicon cells made with Twin Creeks' technology are so narrow that they can bend and flex just like thin film. And they are as efficient as standard silicon cells, Sivaram said, converting as much as 20 percent of the solar energy that falls on them into electricity. Modules from America's leading thin-film company, First Solar, have an average efficiency of 12 percent.
"If this is 16 percent, 17 percent, 18 percent, and it costs less, why would you go with thin film?" said Eric Wesoff, a senior analyst at GTM Research.
The Twin Creeks machine, dubbed Hyperion 3, operates as a particle accelerator, similar to but much smaller than the machines that physicists employ to study the subatomic world.
It energizes protons with 1.2 million volts of electricity and fires them into silicon wafers. At that energy level, the protons penetrate to a uniform depth of 20 microns - with each micron representing one-millionth of a meter - and form tiny bubbles of hydrogen. The wafer is then heated to 600 degrees Celsius, and a layer of silicon 20 microns deep pops off the wafer. The process, called proton-induced exfoliation, is repeated until all the silicon in the wafer has been used.
The standard process for carving up silicon for cells uses wire saws made of steel, yielding layers 200 microns thick. Roughly half the silicon is wasted in the carving process, Sivaram said.
"The way wafers are made is still like 18th century technology," he said.
The Hyperion machine reduces by about 90 percent the amount of silicon that cell manufacturers need and cuts production costs by roughly 50 percent, according to Twin Creeks. Those savings would give Twin Creeks customers a big edge in a business that has become increasingly cutthroat, a business in which rapidly falling prices have already triggered such high-profile bankruptcies as Solyndra's.
Sivaram won't reveal an exact price but said each Hyperion machine will cost "several million dollars." Each will be capable of producing enough silicon layers to make 1.5 million cells per year. Although the company is headquartered in San Jose, the machines will be assembled and tested at Twin Creeks facilities in Mississippi and Massachusetts.
The company has not yet sold any of the machines but is in discussions with several companies in the United States and China.
SOURCE: http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2012/03/13/BUHU1NINMA.DTL
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