Friday Dec 09, 2022

Inside Clean Energy: Think Solar Panels Don’t Work in Snow? New Research Says Otherwise – InsideClimate News


Skeptics of renewable energy often claim—usually with an eye roll—that solar power doesn’t work well in snowy climates.

When most solar panels were stationary and one-sided, this idea carried some weight. But now, most panels move on an axis to follow the sun throughout the day, and an increasing share of panels have silicon on the front and back, making solar more effective even in places with regular snowfall.

Here’s the latest: A recent paper led by researchers at Western University in London, Ontario shows that the use of “bifacial” photovoltaic panels—solar panels that take in sunlight from both sides—produces substantially more electricity during winter compared to using one-sided panels, based on data from a solar array that has both kinds of panels.

“I was surprised how striking the results were,” said Joshua Pearce, an electrical engineering professor at Western University and co-author of the paper. “There is no question now that bifacial modules are the way to go for ground-mounted PV systems in the north.”

The paper, published in the journal Renewable Energy, shows that double-sided panels can take in substantial amounts of energy from light reflected off of the snowy ground at times when the front of the panel is most likely to be partially covered by snow, as described in PV Magazine. 

The researchers went to a solar array in Escanaba, a town in the Upper Peninsula of Michigan. They mounted cameras to observe snow cover, pyranometers to measure levels of solar radiation and also gathered electricity generation data from the system’s operator.

During the cold-weather months of November 2020 to March 2021, the one-sided panels experienced a snow-related energy loss of 33 percent, while the two-sided panels had a loss of 16 percent. The study period included 30 days in which there was snowfall.

Most of the gains for the two-sided panels were because of the reason the researchers expected, which is that sunlight reflected off of the snowy ground and hit the back side of the panels.

But the team found additional benefits in that the snow melted faster on the two-sided panels than on the one-sided ones. This is likely because the panels got warm from absorbing light on the back side, but that’s just a guess since the researchers were not measuring the panel temperatures.

These images were recorded at about the same time at a Michigan solar array. The panels on the right have silicon on the top side only, and are mostly covered in snow. The panels on the left have silicon on both sides and much less snow cover. Credit: Courtesy of Joshua Pearce of Western University

The paper builds on a body of work, including some from this same group at Western University, that suggests what utilities can expect if they build large solar arrays in places that can get several dozen days of snow.

I don’t want to overstate the findings. A solar array in Arizona is still going to produce a lot more electricity per panel than an array in North Dakota, as shown in maps of the differing levels of sunlight across the country. The paper is presenting a more modest takeaway, which is that two-sided panels have big advantages in northern climates that make the projects more financially appealing compared to using the kinds of panels that were most common a few years ago.

One of the moving targets in research about solar panel output is …….


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