It's challenging for people considering solar installations on their property to associate solar energy with snowy environments. It might seem completely absurd to invest in solar installations in regions with heavy snowfall, especially when other renewable alternatives like wind power can take advantage of more extreme weather conditions. Thus, solar energy and snow may appear contradictory and non-functional when it comes to optimizing the electrical production of a solar system, for both commercial and residential projects.

However, this apparent incompatibility can be disproved with simple system adaptations and a few key principles to follow.

Challenges Related to Snow

Numerous challenges arise in northern environments like Quebec, Canada, and the northern states of the USA: For exemple Minnesota, Illinois and Massachusetts. These challenges are multiple and generally need to be addressed simultaneously, implying that the various climatic factors described below must be considered when designing the system.

Solar Panels Covered by Snow

Snow accumulation on modules can lead to several unavoidable issues if the system isn't adapted to the conditions:

• Energy loss: A snow-covered module will inherently produce less energy, or none at all, during the period it's covered. The system's overall efficiency therefore decreases during these periods. A study from the Waterloo university speaks about up to 34% energy loss due to snow cover in cold climates.

• Maintenance cost: In some cases, when the PV isn't tilted enough, it may be necessary to manually clear the module, which can obviously lead to additional costs.

• Wear on solar panels and racking: Some types of PV supports rely on the module structure itself to withstand various types of mechanical stress. It can cause panel bending over time and issues related to electrical components like wiring. Moreover, steel rackings subjected to this kind of stress can be prone to corrosion, which can weaken your system's integrity.

Strong Winds

Snow precipitation can be accompanied by harsh weather conditions, such as strong winds that can affect your system's integrity. Wind loads can cause premature wear on PV modules and supports, with the appearance of cracks or detachment of parts.

Less Light

Snow storms, like blizzards, are accompanied by a decrease in brightness that can lead to a drop in your system's productivity. Off-grid systems that depend on battery installations have everything to gain from greater productivity and optimized efficiency during periods of higher brightness.

Solution: Flat Roofs and Solar Panels in a Snowy Environment

One of the situations where snowy and northern environments can bring issues for solar systems is the installation of flat roof systems. Whether for a factory roof or a house, solar rackings and solar panels on flat roofs present a significant challenge in facing various climatic conditions while meeting the constraints imposed by the building structure.

Indeed, flat roofs are not optimal for evacuating snow and do not easily allow its natural flow. Moreover, these systems are generally highly exposed to all kinds of weather due to the height of the building on which the system is built. Finally, flat roofs are subject to constraints (same as pitched roofs) regarding load distribution and compliance with engineering standards.

Elevating Solar Panel and systems

A first action that may seem obvious but counterintuitive given what the market currently offers is to elevate the system to prevent snow from covering the PV by accumulating on the roof membrane. Therefore, installing solar panels on supports elevated enough to account for snow accumulation allows the system to continue generating energy even after heavy snowfall.

There are other possibilities in case precipitation above average would require manual snow removal. It is indeed possible to clear snow from the roof more easily when the space between the module and the roof membrane is more substantial.

Structural Rigidity

To continue what was described in the previous paragraphs, an elevated solar structure may imply greater wind exposure and therefore require adaptations. One of these is to give your solar system a certain rigidity by using rail rackings that allow designing a system as a whole and linking solar panels together. This rigidity allows better resistance to wind loads and better control of the constraints the system will face.

Moreover, rackings that support the contours of solar modules allow them to withstand the additional load that heavy snow precipitation can induce while maintaining the panel's shape over time. Some solar panels can indeed deform over time with the repetition of additional loads on them.

PV Temperature

An issue in creating a system and its efficiency is the temperature of the modules. They tend to heat up but function better at temperatures below 25°C (77°F). Thus, PV productivity can be optimized in cold and snowy environments provided the panels are exposed. The elevation mentioned previously therefore also allows the panel not to be covered while allowing air circulation and system cooling. Electrical productivity can increase. Wind exposure, which has been compensated for by the system's rigidity, therefore becomes a definite advantage for the installation's productivity.

Solar Racking tilt

More elevation brings many advantages as mentioned previously. PV tilt is an advantage that can also result from elevation. Tilt can indeed be used in the context of solar support for flat roofs when there is an issue of snow runoff. The heat produced by the PV, coupled with its tilt, can serve to make snow that has fallen abundantly on the panel surface flow off.

Bifacial Optimization

An often neglected but decisive aspect in the field remains bifacial gain. By combining the previously mentioned elements: racking elevation, its rigidity, minimizing panel temperature, and adequately tilting the structure, it's possible to optimize the system's bifacial gain in a snowy environment.

How? Thanks to the albedo effect. By using the snow fallen on the ground and combining the previously mentioned elements, we end up with a system that takes advantage of light reflection on snow and produces up to 10 - 25% additional energy with the back of the PV.

Snow: Is It Really a Constraint?

It may be tempting to view snow as an unavoidable constraint that cannot be overcome, implying that certain regions like the northern USA (Minnesota, Illinois and Massachusetts) or Canada are not suitable for the deployment of solar infrastructures. 

Indeed, we demonstrated that by applying a certain philosophy in designing a photovoltaic system on a flat roof, it's possible to take advantage of snow and make it a strength without compromising the integrity of the solar panel and the system.