Solar Coatings Meet Flexible Glass

The illusive market for solar coatings took another step forward in February, when organic coatings maker SolarWindows announced collaboration with Corning for applications utilizing the latter’s flexible Willow Glass. This combination is promising in that the glass can be produced on long rolls and processed – including lamination – at high pressure and temperature in the 500° C range, beyond the capability of solar film.

The Willow Glass, as thin as 100 microns (μm), is said to be capable of supporting thinner backplanes and color filters for both Organic Light Emitting Diodes (OLED) and liquid crystal displays (LCD). The glass also is said to be malleable enough to produce 4000 square feet of glass on one spool; Corning cites availability in widths up to 1.3 meters and lengths of up to 300 meters.

One solar product already on the market utilizing 2 mm flex glass is the 2.5 kilowatts-per-hour SmartFlower, from Austria, a flower-shaped set of solar petals that follows the sun on a double-axis tracker. The residential or commercial product, with 18 square meters of thin film solar panels laminated to flex glass, is available for about $10,000.

The most likely near-term application for the solar flex glass or veneer, as the company prefers to label it, is in commercial Building Integrated Photovoltaic (BIPV) retrofitting or new construction, with a payback of less than the expected 20 year warranty for the solar photovoltaic production. SolarWindows has been working with the U.S. Department of Energy’s National Renewable Energy Laboratory under a commercialization agreement for some time.

“While generating electricity on flexible glass presents obvious commercial opportunities, this approach is especially attractive to high-speed roll-to-roll manufacturing for maximizing output while lowering production costs,” said Dr. Maikel van Hest, a senior scientist in the Thin Film Material Science and Processing Group within the Material Science Center at NREL.

The NREL agreement is a Cooperative Research and Development Agreement (CRADA) under which SolarWindow began work in March 2016 to jointly “enhance product performance, increase scale, and improve reliability; and develop new features and obtain important performance certifications required for a commercial rollout,” NREL notes.

In addition, the team will focus on various SolarWindow product-specific goals, including: “large scale window fabrication; interconnection development for easy ‘plug-n-play’ on-site installation; advanced performance measurement and modeling of SolarWindow when installed in various building types and geographies; and SolarWindow performance under varying artificial and natural light conditions,” NREL noted.

Other flexible solar glass applications include transportation, where smart glass applications could co-exist on solar glass windshields and other glass surfaces. Similarly, flexible glass, which weighs very little, can be incorporated into electronics devices, clothing, and a variety of military mobile applications.

The value of the flexible solar glass market is difficult to estimate, given the novelty of the technology, covered under a host of patents. One market research house indicates that the global flexible display market is expected to approximate $4 billion by 2020. Another research report suggests that some $40 billion in value is added to the basic $20 billion-plus global flat glass market by laminating, tempering, coating and silvering processes.