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Home arrow Blog arrow 9/8/06, German approach might energize solar industry

9/8/06, German approach might energize solar industry PDF Print E-mail
Written by Tom Abates   
Friday, 08 September 2006
Is the sun finally ready to shine on the solar industry?

That question is getting asked more often in clean energy circles these days, in part because Applied Materials Inc. -- the Santa Clara company best known for selling the tools that make computer chips -- recently tiptoed into solar energy manufacturing.

For decades solar cells have lived in the shadow of their close cousins, computer chips. Both are semiconductors -- devices that can be induced to either block or conduct electricity.

But while computer chips are now so cheap they're everywhere, solar cells generally remain too costly to install without some form of subsidy.

As the pre-eminent developer of chip manufacturing systems, Applied Materials certainly shares the credit for driving down chip prices. So when it recently acquired a solar manufacturing process developed in Germany, astute observers took note.

"This provides credibility for the (solar) industry," San Francisco investment banker Neal Dikeman wrote in the Cleantech blog.

Observers say Applied Materials may see an opportunity to enter the market for developing tools to create a potentially cheaper type of solar module by spraying a thin layer of silicon onto glass, an approach sometimes called thin-film solar.

Although thin-film solar isn't new, the German approach offers promising refinements that could make this process more competitive with the more common practice of using slices of silicon -- called crystalline solar -- to convert sunlight into electricity.

Interest in thin-film solar has been on the rise recently owing to price increases in the most commonly used semiconductor material, silicon. Whether this new process, now backed by Applied Materials, accelerates cost reduction and ultimately a wider adoption of solar power remains to be seen. But this development is indicative of the current ferment in solar, as rising oil prices and global warming worries fuel a range of approaches to making the cheapest system that can suck the most power out of sunlight.

Applied's solar gambit offers lessons on innovation, starting with how subsidies -- in this case paid by the German government to scientists in that country -- spur developments.

"Everybody is convinced (subsidies) created the solar industry (in Germany)," said Joachim Nell, one of the technologists who developed the production system now owned by Applied Materials.

Showing the process

During a recent visit to his new corporate bosses in Santa Clara, Nell described the process that Applied Materials acquired in July as part of the $464 million acquisition of a Colorado company, Applied Films, that had previously owned the German technology.

A good place to begin is in the late 1990s, when a German glass-finishing company started collaborating with researchers, led by Stephan Wieder, who had government support to develop approaches to solar energy.

As Nell explained, the German company was already in the business of manufacturing flat-panel television displays. This involved depositing thin layers of electronic materials onto glass. One question the German innovators asked was whether this manufacturing expertise could be repurposed to a similar task -- coating glass with a thin film of silicon to create a cheap but effective solar module.

The idea of spraying a thin layer of silicon onto glass is nothing new. Solar energy pioneer Stanford Ovshinsky has spent decades pushing what the industry calls amorphous or thin-film solar. Solar calculators are a common example of this technique.

But calculators don't need much power, and more than 90 percent of all the solar energy being generated today is derived from a different technology, called crystalline silicon. It uses slices of semiconductor material, most commonly silicon, that sit side by side like so many slices of bologna. Crystalline solar is preferred because it is more efficient at turning sunlight into electricity. The typical crystalline solar cell will convert 15 to 20 percent of the sunlight it captures into electricity. Thin-film solar systems tend to have from 6 to 10 percent conversion efficiency.

Of course, all this was known to Nell and the other German innovators, who faced two challenges in retooling their flat-panel display process to make thin-film solar modules. In the lab, they had to get the best possible light-to-electricity conversion ratio. In the factory, they had to make sure their process could mass-produce this photovoltaic magic.

Their scientific solution, as Nell explained, was to marry thin-film and crystalline technologies in a hybrid process called tandem solar. The German researchers first sprayed a thin silicon film onto the glass. Then they added a second layer of microcrystalline bits -- too small to see but big enough to capture some of the photons that got through the thin film.

The manufacturing trick was to make these chemical processes work inside the giant machines they used to deposit the proper chemistry -- in this case the thin film and microcrystalline bits -- onto big sheets of glass.

About 16 months ago this marriage of science and manufacturing bore fruit.

"In April 2005 we announced that we were able to come up to 10 percent efficiency with this tandem process,'' Nell said. This light-to-electricity conversion ratio was achieved on a piece of glass nearly 9 feet square -- too big for a solar calculator but large enough to put on a roof.

In June a division of Q-Cells, the world's second-largest solar manufacturer, ordered three of these tandem solar production systems. At Applied Materials headquarters, Nell would say little about that sale other than that it was a vote of confidence in the new process.

Hampered by rising prices

Meanwhile, all solar power innovators are grappling with the silicon price rise while trying to capitalize on the renewed interest in the field. Market expert Paul Maycock with PV Energy Systems said that in 2002, the cost of silicon was about 12 percent of the manufactured expense in making a crystalline solar module. Today, silicon raw material costs constitute about 20 percent of the total manufacturing outlay -- spurring interest in all sorts of efficiencies, from thin film to thinner crystalline slices to alternative semiconductor materials.

For instance, San Jose's SunPower Corp. is mass-producing what may be the world's most efficient solar cells -- turning more than 20 percent of sunlight into energy by using slices of crystalline silicon.

In a different vein, Palo Alto's Nanosolar Inc. recently announced plans to build a $100 million factory to create a new type of thin film solar cell. It will not use silicon but a different semiconductor -- copper indium gallium diselenide or CIGS.

Other entrants are mixing and matching techniques.

Miasole, a solar startup in Santa Clara, is basing its approach on hard disk manufacturing techniques. Drivemakers deposit fine layers of magnetic particles onto the metal platters inside drives. Why not spray on thin layers of solar materials?

While that adaptive approach resembles the Applied Materials process, Miasole will spray its thin films on flexible stainless steel rather glass. And like Nanosolar it will use CIGS not silicon as the light-capturing semiconductor.

The challenge facing all these solar aspirants is summed up in a 106-page report issued in July by Lehman Bros. analysts who offered a neutral investment outlook on the industry:

"Solar energy remains the most expensive source of energy being 10 times more expensive than conventional fossil fuel electricity," they wrote, adding that sales growth remains dependent on "favorable government incentives."

In light of such caveats, the way that Applied Materials is entering the solar tools business is instructive. Company spokesman Dave Miller noted that his company got more than the solar process in the acquisition that closed in July. It also got market share and technology in flat-panel display manufacturing -- which already accounts for about 10 percent of its business.

But the company clearly has an eye on solar tools. At a luncheon shortly after the acquisition closed, Applied Materials chief executive Mike Splinter told a group of reporters that solar still generates an "infinitesimal" amount of the world's electricity due to its expense relative to other energy sources. "We should be able to drive (down) the cost," he said.

Applied Chief Technology Officer Mark Pinto said the trend was their friend. "We're bringing (solar) prices down," he said. "Energy prices are going up."

The final chapter in this innovation parable may be the way in which the beneficial madness that has long been a hallmark of Silicon Valley seems to have smitten the German team that brought the solar manufacturing process to Applied Materials.

"They were dreamers, freaks," Nell said of his German colleagues, adding: "In 1999 nobody saw (this becoming) an industry."

Last Updated ( Friday, 08 September 2006 )
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