By Jeff Pipeling
As winter is upon us in the Northeast, quicker than some may have hoped, with snowfalls ranging from 0″ in southern CT to 16″ in Northwest CT and parts of Vermont, the question new solar homeowners may have is, “What happens to my solar panels when it snows?”
Solar produces power with direct sunlight, the photons of the sun excite the electrons in the cells of the panel and create and electric current that is inverted into AC power to offset the expensive electric grid power. “But does it work when it snows?” Yes, it does. When it is snowing the panels are still creating power and therefore creating heat which melts the falling snow and still allows the panels to produce power, albeit less power than a clear sunny day, but still power.
“What about when there is a lot of snow, and the panels cannot keep up with melting the snowflakes fast enough?” The panels will get covered during large storms, and eventually will stop producing. “So what do you do? How is the system supposed to work effectively if it is covered in snow?” The easiest answer is they do not need to work when covered with snow because when the system is designed correctly, you will be carrying overproduction credits of power from the fall, summer, and spring into the winter. Net metering means your solar system has a virtual bank of power that builds up on the grid so that you do not have to worry about the panels being covered for a few days during a snowstorm.
“What do you do when the solar panels are covered?” The question that really needs to be answered is what do you do when the roof is covered Now? If the answer is nothing, and you have no issues with snow build up, ice damming, or the weight on the roof, the same answer applies to solar. Each system must have an engineered stamped letter stating it can hold the weight of the solar panels, equipment, and the snow. So if you have no issues now, you will most likely have no issues with solar. In fact, you will have less, because while the roof shingles have granules and tend to hold the snow on the roof, the solar panels are a sheer surface with little to no surface friction and the snow will slide right off once the sun comes out.
The pitch or angle of the roof however, does matter. A shallow pitch will hold snow longer while a steeper pitch will shed the show quicker. A good rule of thumb is that if the roof pitch is 20 degrees or more you typically can expect the snow to slide off by itself. However if it is a lower slope than 20 degrees, you can plan to have more credits built up or oversize the system, or use a soft roof rake to help pull snow off of the bottom of the panels and the rest will slide off.
Snow does build up on solar panels and on steeper pitched roofs it will slide off all at once. Typically, if this happens when no one is below the solar array there are no issues, just some extra shoveling. However if over an entry door, snow guards can be strategically placed to divert snow fall away from the entry.
Finally, design is important. Make sure that you’re dealing with an experienced solar consultant who knows how to design a solar system, not just a salesperson who may not understand the physics involved. The design of multiple arrays on a single rooftop must be accounted for when considering snowfall amounts. Bushes, glass enclosures, or sunrooms also need consideration in the design stage. As long as snow issues are taken into account before your solar installation with your consultant and the NABCEP (North American Board of Certified Energy Practitioners) designer, you can feel confident that your solar project will be able to handle the New England snow year after year and keep saving you money on your the electric bill that would otherwise be escalating year after year if you didn’t have the solar.
Jeff Pipeling is the General Sales Manager at C-TEC Solar. Working one-on-one with thousands of homeowners in the solar industry, for more than 6 years, has given Jeff broad knowledge and technical understanding of the industry.