[Image above] Michigan State University materials scientist and chemical engineer Richard Lunt holds up a prototype of a clear solar cell. Credit: National Science Foundation; YouTube

There’s a tremendous amount of solar energy radiating from the sun each day—and that energy could be ours for the taking. In fact, commercialized solar energy use in the U.S. spiked 33% in 2014, thanks to soaring solar industry expansion.

But the sun’s power needs to be captured and efficiently stored if it’s ever going to be our go-to energy source over fossil fuels.

Scientists and engineers know this, and they’re working on making solar panels more efficient and more cost-effective to produce.

In September we reported on research from the Department of Energy’s Los Alamos National Laboratory (N.M.), where scientists are developing a new sunlight harvesting technology that can turn a nearly transparent window into an electrical generator using “quantum dot solar windows.”

But what if there’s a solar energy harvesting solution that doesn’t involve building new windows or developing a new type of glass?

Engineers at Michigan State University say there’s a ‘clear’ alternative to existing photovoltaic technology that can be retrofit to existing glass-covered buildings… and it’s scalable.

With support from the National Science Foundation, Michigan State University materials scientist and chemical engineer Richard Lunt and his team are developing transparent solar panels that are completely clear and flexible that can be retrofit to cover existing windows instead of replacing them outright.

“Traditional solar panels, such as silicon, soak up much of the sun’s light, including visible light, and convert it to energy. A transparent panel allows visible light to shine through, by making the light we can’t see with our eyes—such as ultraviolet and infrared—do the work,” explains an NSF news release.

In an NSF video about the technology, Lunt takes us into the lab to demonstrate some of the recent research and development—and the challenges he and his team still face when it comes to developing solar cells that are completely clear.

Credit: National Science Foundation; YouTube

One solution the team has come up with involves layering patterns on the solar cell in a way that makes them uniformly clear.

“We actually use a variety of different stencils to pattern our devices,” Lunt explains in the video. “Each active material will have its own pattern. After every layer we put down a new stencil, and this way we can build up very complex structures.”

The team isn’t limiting their materials to glass structures. Margaret Young, materials science engineer at Michigan State University, is testing whether the same pattern-layering process can be used on thin plastic, which could provide a cost-effective solution for retrofitting this technology on existing windows.

“[Plastic] is much lighter and much more flexible. So instead of rebuilding windows, we could just put this over existing windows,” says Young in the video. “With the square footage of glass that’s on our skyscrapers and buildings, there’s so much square footage that can be used to generate power.”

Lunt says his transparent cells are already relatively inexpensive to produce and have major scale-up potential.

“I think in the next 20 years we’ll see this type of technology get deployed so that it’s all around us generating power in the background and really turning our cities and landscapes into solar harvesting systems,” says Lunt.