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Take reflected light into account with these two-sided panels.

Andrew Blok has been an associate editor at CNET covering HVAC and home energy, with a focus on solar since October 2021. As an environmental journalist, he navigates the changing energy landscape to help people make smart energy decisions. He's a graduate of the Knight Center for Environmental Journalism at Michigan State and wrote for several publications in the Great Lakes region, including Great Lakes Now and Environmental Health News since 2019. You can find him in western Michigan watching birds.

If you've ever needed to put on sunglasses while facing away from the sun, you understand the benefit of bifacial panels. Because sunlight reflects off of most surfaces and solar panels use sunlight to generate electricity, a bifacial solar panels collects sunlight on both its front and back.

Bifacial solar panels can produce more electricity than their conventional counterparts, but only if they have space for reflected light to reach the back side of the panel. That means they work best in specific applications, and not when they're stuck right against your roof. If you're putting solar panels up on a pergola or a ground mounted system, bifacial panels might make sense.

If you're thinking about installing solar at home, read up on the best angle to install panels , local and federal tax incentives and how many panels you'll need to power your house. 

Sunlight reflects, to varying degrees, off of everything. If you've ever been outside after dark when there's snow on the ground, you've probably noticed how much lighter it is than without snow. This effect even has climate change implications. Research shows that ice reflects about 85% of sunlight, but open water reflects only 7%. As Arctic ice melts, the water underneath absorbs more light (and heat).

All this to say, there's enough light bouncing around to generate electricity on the back side of the panel too. To take full advantage of bifacial panels, there are a couple key considerations.

First, the more reflective the environment around the panels, the more energy they'll generate. A lighter colored environment will reflect more light and boost performance. "We're seeing that as the grass turns brown, it gets more reflective, and snow cover is great," one researcher said in a report from the National Renewable Energy Laboratory. It also means that desert countries, like Australia, with lots of reflective sand adopt bifacial panels quicker than their neighbors, the consulting firm Wood Mackenzie reported.

Second, there needs to be space for reflected light to reach the back of the panel. This means bifacial panels don't make sense for rooftops where they'll sit almost right against the shingles. They're best utilized in large, commercial installations where they're up in the air on poles, with plenty of space for light to reflect against the back. 

Bifacial panels outperform traditional, one-faced panels throughout the year. Under ideal conditions, bifacial panels can produce 27% more energy.

Bifacial panels don't cost much more than other solar panel options, so they're attractive options if you have a suitable place for them. Even though there's no benefit to installing them on a roof, homeowners might opt for bifacial panels in a few instances.

If your solar panels are mounted on the ground instead of a roof, bifacial panels could be a good choice. This is especially the case if you live in a snowy area or can install them over a more reflective surface, like sand.

Bifacial panels can also be beneficial if they're being used to build a covering over an outside area. A pergola or awning with an open space underneath will be far enough from the ground to allow reflected light to reach the back of the panel. Creative folks will likely find other ways to deploy bifacial panels.

Despite being unhelpful in most residential applications, bifacial panels are one more tool that could help you squeeze a bit more energy out of the sun. Using them in the right situation can help you achieve your energy goals for just a small premium.