Wednesday, July 3, 2013

Flexible Glass Could Make Tablets Lighter and Solar Power Cheaper | MIT Technology Review

Flexible Glass Could Make Tablets Lighter and Solar Power Cheaper | MIT Technology Review
Based on tests by Corning, which makes a product called Gorilla glass for iPhone screens and which announced the flexible material, called Willow glass, last year, shingles made from such solar cells could last for decades on a roof—even weathering hail greater than three centimeters in diameter. Conventional solar panels are heavy, bulky, and breakable, which makes them expensive to transport and install.
The new solar shingles could be nailed to a roof in place of conventional shingles. Rather than paying a roofer to put asphalt shingles on a new home, and then paying solar installers to climb back up and mount solar panels to the roof, the roofers could install solar shingles instead of asphalt ones. The only added labor cost would be hiring an electrician to plug the array of shingles into an inverter and connect it to the grid. Thin, flexible solar shingles could also be shipped more cheaply.
The cost of installation is one of the largest parts of the overall cost of solar power—its share has increased even as the cost of the cells themselves has plummeted in recent years. Indeed, installation and other auxiliary costs are now the biggest opportunity for reducing the cost of solar power. An average rooftop solar system in California costs $6.14 per watt, while solar panels themselves sell for less than $1 a watt in many cases.
Solar shingles are already available (see “Solar Shingles See the Light of Day” and “Alta Devices Plans a Fast-Charging Solar iPad Cover”). The chemical giant Dow makes them, for example. But they are typically made of plastic. Glass-based shingles, as counterintuitive as it sounds, could be more durable, says Dipak Chowdhury, division vice president and Willow glass commercial technology director at Corning. Glass is very good at sealing out the elements, which can help solar cells last for decades. It’s also surprisingly strong, and, in its flexible form, resilient. “We knew from our optical fiber work that glass is actually stronger than steel when you try to pull it apart,” he says. If Willow glass shingles were hit by hail, they would flex rather than break. While other solar shingles can also withstand hail, they may not be as good at protecting solar cells from air and moisture, he says.
The glass also makes it possible to use cadmium telluride as the solar cell material. This is the only material that’s been able to successfully challenge conventional silicon solar cells at a large, commercial scale (see “First Solar Shines as the Solar Industry Falters”). Cadmium telluride solar cells need to be made on a transparent material. Other flexible, transparent materials either can’t handle the high temperatures needed to make the solar cells, or they block too much light, reducing efficiency.

No comments:

Post a Comment