Quantifying Snow Losses
The visual of snow-covered panels often leads to exaggerated estimates of energy loss. To determine the actual impact of snow accumulation, the Northern Alberta Institute of Technology (NAIT) conducted a comprehensive five-year study on solar performance in high-latitude, snowy climates.
The data revealed that the annualized energy loss due to snow accumulation was between 3% and 6%. This figure is statistically minor because the majority of annual solar generation (approx. 75%) occurs during the spring and summer months when irradiance is highest. Losses incurred during the low-production winter months have a negligible impact on the system’s total annual yield.
Mechanical Shedding and Self-Cleaning Properties
Residential solar arrays in Ontario are engineered to mitigate snow accumulation through passive shedding.
- Installation Angle: Panels are typically installed at a tilt angle between 30 and 45 degrees, leveraging gravity to facilitate snow slide.
- Thermal Dynamics: The dark, anti-reflective glass of a solar panel absorbs solar radiation, creating a thermal differential that lubricates the glass surface, causing snow sheets to slide off efficiently.
Professional Advisory: Risk Management and Maintenance
A frequent inquiry regarding winter maintenance is the necessity of manual snow removal. The consensus among industry professionals is to avoid manual intervention.
- Warranty Integrity: The use of abrasive tools (roof rakes, shovels) carries a high risk of scratching the tempered glass or damaging the anti-reflective coating, which can void the manufacturer’s warranty.
- Safety and Economic Viability: The marginal economic gain of recovering a few kilowatt-hours of winter production does not justify the safety risks associated with roof access in icy conditions.
I was surprised how much production I still got with solar on cloudy days and even in the winter.
– Victoria Fawsitt
