For decades, generating solar energy meant installing large black solar panels on rooftops. But what if you could harness the invisible light coming through your windows to generate electricity?
That’s the promise of solar windows — a cutting-edge technology that could transform the way we build sustainable infrastructure and generate electricity in the future.
The technology was created by researchers at the Massachusetts Institute of Technology, who turned their development into a company called Ubiquitous Energy, and a solar window product called UE Power. Ubiquitous Energy says its fully transparent solar window panels are “the world’s first aesthetically acceptable electricity-generating alternative to traditional windows.”
A conventional solar panel is designed to capture every photon of sunlight that falls on its surface. But UE Power lets visible photons pass through the glass while capturing invisible light — specifically ultraviolet and infrared light. This invisible light is then converted to electricity, which is then guided by thin wires protruding from the windows and connected to the building’s wiring, just like a standard solar system. The result is a pane of glass that looks like a normal window, but which generates electricity.
“The magic of transparent solar is that we can embed solar technology into products that already exist, because you don’t have to see it,” said Ubiquitous Energy CEO Susan Stone. “It’s just any other solar system, but it happens to be vertical rather than horizontal.”
The company has rolled out UE power at 12 pilot facilities, including at Michigan State University and its headquarters in Redwood, California.
The panels are small right now — about 14 by 20 inches — but the company is drawing up plans to build its own production facility to produce floor-standing solar glass panels for commercial applications. These commercial panels cost 30% to 40% more than traditional “passive” glass, Stone said.
While you can’t buy solar windows for your house just yet, the company has partnered with glass maker Andersen Windows to sell the panels for residential use.
Capturing only part of the light from the sun does mean that these panels are not as effective as traditional solar panels. Stone says their technology is about 20 percent as efficient as state-of-the-art solar panels. But unlike those panels, which need to be installed in a specific way, Ubiquitous Energy says its product can be installed anywhere ordinary glass is placed.
In the short term, this means homes and office buildings can generate their own electricity and rely less on the grid. In the future, Stone said, the technology could be used to create smart windows that power their own sensors.
“For example, they allow a family home to respond to its environment,” she said. “Sensors can tell you, ‘It’s raining, close the windows’ or, ‘It’s hot inside, it’s cool outside, open the windows for mechanical ventilation.'”
For the future, Ubiquitous is also looking at applications beyond residential and commercial buildings.
“One of my favorite places to install solar is my phone battery,” Stone said. “It would be great if all the cars parked in the parking lot could generate electricity.
“If you didn’t need to see solar energy, where would you put it?”
To learn more about solar windows, check out this week’s “What’s the Future” episode embedded at the top of this article.