Coatings World - May 2012

PPG Launches Solar Glass Coating

by Charles Thurston, Contributing Writer

PPG recently launched a new anti-reflective coating for glass panels used in solar modules, increasing the amount of electricity produced by three to five percent and reducing heat, according to Richard Beuke, PPG’s vice president for flat glass, in Pittsburgh, Pa.

The company spent nearly four years developing the angstrom-thin coating, which includes layers of titanium dioxide, silicon dioxide and magnesium, branded Solarphire. To better serve the solar manufacturing industry, largely located on the West Coast, PPG also has amplified its Fresno, Calif., glass plant and its Salem, Ore., coatings facility, at a cost of about $12 million. The company also recently formed a Solar Performance Group.

The coating is applied through a magnetron sputtered vapor disposition process under vacuum, which permits more sophisticated chemistry than competing processes not utilizing vacuums, Beuke said.

Among other products PPG makes for the solar industry is a sodium barrier layer, which prevents sodium migration from the glass to reach non-silicon-based solar cell materials, particularly those operating at higher temperatures using concentrated solar technology. The company also makes coatings for reflecting mirrors utilized for enhancing the efficiency of either flat panels or concentrated solar collectors. PPG’s coatings can be applied on either or both sides of a glass sheet.

“Our market is the U.S. solar module market,” said Beuke.
“Thus far we are not exporting the product, but modules made
with our coatings are being exported.”
The total value of the U.S. solar market is estimated at $8.4
billion by Solar Industries Energy Association. U.S. solar module
makers produced 1,219 megawatts of panels last year, with 6,000
to 8,000 panels per megawatt common, depending on the tech-

PPG’s solar coating, Solarphire, is an anti-reflective coating for glass panels used in solar modules.

nology utilized in the solar cell. Currently, the U.S. produces seven percent of all solar panels made globally, and that percentage share is expected to increase to 15 percent by 2016, according to a projection by Greentech, a renewable energy analyst.

The cost of a watt of installed solar panels averaged four dollars about five years ago. Today installed costs are little more than one dollar per installed watt. As a result of the price drop, a substantial improvement in panel efficiency, like that yielded by the Solarphire coating, can make a panel more competitive in a highly competitive market. Several U.S. solar module makers have filed for Chapter 11 protection under U.S. Bankruptcy code over the past six months.

Much of the price reduction in solar panels has taken place since China began subsidizing the production of cells and panels to build up its nascent solar industry. In March, the U.S. Commerce Department announced import tariffs of up to 4.73 percent on Chinese solar panels, with the potential for the amount to increase in May, when dumping charges have been analyzed more thoroughly. The dumping charges have been lodged by the Coalition for American Solar Manufacturing, representing various U.S. solar panel makers.

“Traditionally PPG is thought of as an organic coatings company, whether the industry served is automotive or industrial, but we also produce a lot of inorganic coatings, like Solarphire,” Beuke said. “The most sophisticated type of low-E glass, for example, is produced with 17 layers of mixed metal oxides on the glass.” CW