Removing snow from solar panels has been a regular debate for the last decade. Various studies claim only a small percentage of production is lost from snowfall. Is it really worth tacking on snow removal O&M costs?
Janitorial solar O&M companies, like Solar Maid, say yes, but not for production claims. Safety concerns are becoming louder in the solar industry. While experts (and Solar Maid) suggest giving Mother Nature time to melt snow off tilted panels, that falling snow can be problematic, especially on public solar arrays like carports.
“It’s becoming a pretty big issue now,” said Jay Welsh, general manager of Solar Maid. “We’ve really seen a spike this year in business.”
Founded in 2003, Solar Maid specializes in janitorial solar O&M—panel cleaning, landscaping, pest abatement—and is headquartered in Pittsburgh but has affiliates in nearly every major market in North America. Snow removal from a safety standpoint is more prevalent on residential and commercial projects. Utility-scale solar arrays turn to Solar Maid in the winter specifically because of production losses.
“Some of those bigger sites lose $80,000 a day when those things aren’t producing,” he said. “They’ll pay us $5,000 or $10,000—it’s certainly a cost benefit.”
Solar Maid uses its own snow rakes to push and pull snow off arrays. Pricing is based on type of snow—wet, heavy snow is more expensive than light, powdery snow just because of time involved to remove it.
“Carports are easier. You just pull the snow off, then we use a plow and push it out of the way of the parking lot,” Welsh said. “Our rooftop commercial jobs are a bit of a challenge because you have a lot of wires and cabling between the panels, so there’s really no place to put the snow. We’ll set up tarps, push snow on the tarps and then drag the tarps to the edge of the roof and then dump them. Every site is going to present some challenges.”
Solar Maid has been installing more snow guards on its residential arrays to prevent snow and ice from falling off the roof.
“Typically, snow falls and then the sun comes out and warms up and that bottom layer of snow starts to melt,” Welsh said. “It may not melt enough to push the snow off, but then it freezes again. Then you have a sheet of ice, and it snows on top of it. It’s likely not going to stay in one place. If the panels happen to be on the front of your house, if you slam your front door shut, the snow avalanches.”
“Block guards” are randomly placed and clamped to the edge of panels to stop ice sheets, while the typical “snow guard” acts as a lip, attaching to the end of panels to hold back snow.
Solar mounting manufacturer EcoFasten Solar and its sister company Alpine SnowGuards offer a snow management system for solar panels—Solar SnowMax. Made of aircraft-grade aluminum fabrication, it’s strong and rugged and clamps directly to the solar panel frame.
“This snow management system was designed to impede a sudden avalanche of snow,” said Brian Stearns, president and founder of EcoFasten Solar and Alpine SnowGuards. “Snow will still crest, rise up and over the top of the snow management system and fall to the ground in a controlled manner. Solar SnowMax allows smaller, managed amounts of snow to drop to the ground slowly, without that massive rush of snow shooting off the roof that you sometimes see in the phenomena of a roof avalanche, especially on frictionless surfaces, such as solar panels or metal roofs.”
So while production losses on small residential and mid-size commercial projects aren’t worrisome when snow falls, it’s wise to keep in mind all safety concerns. Find a snow-specific O&M company in your area, buy your own snow removal gear or install snow guards to gain some peace of mind. SPW
Daniel Keiley says
Kelly,
I am getting calls from homes with recent solar installs expressing concerns with the occasional “Avalanche” of snow coming off their panels. I have visited two of these homes.
Roofs and Solar panels cause a “Slab Avalanche”. The most dangerous type of avalanche.
There is a cascade of oversights and design errors here.
1) A house in snow country should be designed to shed snow safely from its roof, protecting the safety of the occupants coming and going, solar panels or no solar panels.
2) The solar panels make the problem worse with their slick surface.
I do not mount panels on roofs that drain onto sidewalks, entryways, driveways, or garage door openings. All solar designers and installers should be armed with this knowledge.
I am brainstorming solutions for the unfortunate owners of solar whose designers failed to account for snow safety. Looking at your snow guards.
David Blume says
Seems like someone would come up with a liquid solution for year round use to lower panel temps in summer months and warm in winter months. DC motors and pumps use low amperage and can be PLC controlled .
Mike Millert says
How about transparent mylar sheets with heat wire like they use for rear window defrost in cars?
Gene says
Hi Kelly,
Interesting article, however it still doesn’t resolve the issue. Why couldn’t they design something that we could turn on with the light switch warm up the panels enough to melt the ice in the snow from the panels? Maybe use the same technology that they use for creating warm floors and household? Or maybe the same technology they use to melt ice from driveways? With the huge increase of solar panels just in the New York state area you would think this would be a priority? We need advocate like you to help us “solar panel owners “resolve the situation so we can maximize our solar panels capabilities of generating energy.