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.
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