For those looking for the short answer: no, you have nothing to worry about, your solar system will operate as normal, and are designed to handle any of the elements. Any reputable solar designer/contractor would have designed a system to fit your needs. And that means sizing-up to meet your annual production needs, not per your solar demands within a short duration (say December or "last weekend when it snowed"). The rule of thumb (without fancy ROI calculations or detailed modeling based on your smart-metered electrical usage) is to eliminate 80% of your electric demand usage with solar energy as your best "bang for your buck." Therefore, the weather that we can predict for the wintertime are normalized and accounted for on an annual basis. [For more info on this, the industry standard is NREL's (National Renewable Energy Laboratory's) TMY3 data sets, which is derived from decades worth of weather station information, used to determine a "typical meteorological year," valuable when sizing-up your solar energy production within a year's timeframe).]
So back to the blog postings from several of the largest solar companies. Sunrun offers up several entries on solar in the winter. One in particular reminds their customers that there will be shorter days, and as a safety pre-caution to not remove the snow physically from roofs. Good info for sure, but maybe we can delve into a bit more detail. Solarcity, on the other hand, offers a bit more insight with their post of "How Snow Affects Your Solar Power System."
Similarly, the post echoes calls for safety and setting up correct (imho) solar expectations for the wintertime. But then it goes into research areas that made me perk up and take notice. Solarcity claims that "You may actually see an increase in production after the snow clears from your system. Solar panels perform better on cold sunny days than hot ones, and in some cases snow cover might even help production by reflecting sunlight." They link an article from a CleanTechnica website which references research from Michigan Technical University (there are others obviously) on a common solar phenomenon called the "albedo effect." Without getting overly technical, albedo influences the amount of solar sunlight that a given surface will encounter, in this case the albedo of snow having an effect on the solar production of module panels.
Although technically true, I recognize that solar production could be increased with the presence of snow; the key difference is that the research studies the effects of snow on the ground for "huge commercial solar farms." It would be fairly easy for me to argue that the presence of the snow and its albedo will have an entirely different effect on solar modules mounted up high on rooftops. In any case, it would seem interesting that Solarcity would bring up this topic when their main business is residential solar rooftops, and definitely not solar farms. It seems intellectually lazy at
best, and intentionally deceiving at worst. I would definitely not have made such claims.
At any rate, main takeaway for my readers is that we (of the solar industry) understand full-well that energy production will take a hit in performance during the winter months; the industry designs a system with the entire year’s production in mind. Snow can fall and accumulate on the panels. As long as the panels are not at a flat 0 deg tilt (highly not recommended), the snow will melt and come right off the panels.
Feel free to contact me directly with any questions or clarifications.