Wayne Boor, manager, solar technology transfer, PPG Industries' (NYSE:PPG) performance glazings business, said industry forecasters expect solar glazings to account for 10 to 20 percent of flat glass sales, if not more, by 2015.
As part of a presentation at the Glass Association of North America’s (GANA’s) Solar Symposium in July, Boor said he expects the rise of solar glazings to resemble an earlier era of glass industry innovation, the growth of automotive glass. He explained that prior to 1900, nearly all flat glass manufactured in the United States was for architectural applications. By 1940, automotive glass accounted for about 25 percent of all flat glass sales. Boor said he sees a similar arc for solar glazings, which now account for about 2 percent of flat glass sales.
He also identified other historic parallels. For instance, Boor said the first architectural glasses were clear, but the industry eventually discovered that tinted coatings could help keep building interiors cool. Similarly, clear glass was the precursor to advanced solar glazings, which eventually incorporated coatings to promote higher levels of light transmittance, durability and conductivity, along with ultra-low iron formulations to improve solar transmittance.
To increase the efficiency of solar glass, Boor said PPG is working closely with industry leaders to advance several technologies. The first is to make glass substrates more transparent to solar energy. This is being done by combining special low-iron batch materials with proprietary process techniques to lower iron “redox,” which selectively improves infrared transmittance.
PPG also is developing thin-film coatings that prevent sodium migration under high temperatures, introduce surface conductivity or make solar glazings either anti-reflective or highly reflective, depending on the desired property. Individually or in combination, these attributes can significantly enhance solar technology performance.
Finally, for concentrated solar power (CSP) applications, Boor said he sees a movement toward self-cleaning solar glass that maintains mirror reflectivity and performance.
PPG has a team of commercial and technical personnel devoted to working with solar industry leaders to develop glass substrates and coatings that improve the energy- and cost-efficiency of solar power.