Solar panels and wind: Do they hold up?

Weather events like hurricanes are accompanied by wind speeds up to 200 miles per hour, and tornadoes can bring even higher speeds that threaten to damage rooftop and ground-mounted solar energy systems. If you live in a windy area of the country, it is especially important to know how your solar energy system will hold up during a storm.

Generally, solar panels are highly resistant to damage from windy conditions. Most in the EnergySage panel database are rated to withstand significant pressure, specifically from wind (and hail!) The weakest link for the wind resistance of a solar panel system is rarely the panels themselves – in most instances where wind causes damage to a solar array, failures occur due to weaknesses in the racking system or the roof the panels are affixed to.

When the wind blows across a roof with solar panels, it passes through the small gap that typically exists between the panels and the roof (or between your panels and the ground in the case of ground-mounted systems), causing a large amount of uplift to the panels. This phenomenon can tear panels from their mounts or the mounts from the roof or ground. In the most extreme cases, solar panels may stay anchored down, but uplift from strong winds can tear sections of your roof off. Cases like these show that a well-built solar racking system may be more resistant to high winds than your roof itself.

Another potential source of panel damage during wind storms is flying debris. Although more unpredictable than wind alone, due to the variety of sizes and types of materials that can be blown around in a storm, solar panels have proven to be remarkably resistant to impact from wind-blown debris in the past. At the National Renewable Energy Laboratory (NREL) campus in Golden, Colorado, a severe hailstorm resulted in one broken panel out of 3,000 in a large rooftop array. While not a perfect predictor of a solar panel's ability to withstand debris, this case is an encouraging reminder that solar panels are hard devices capable of surviving varying weather events.

If you live in an area with frequent hurricanes (like Florida) or tornadoes (like Texas or Oklahoma), your local government likely has policies that mandate a level of durability for rooftop solar arrays. For example, in some areas of southern Florida, where hurricane season predictably brings extreme winds every year, solar panels must be installed to withstand winds up to 170 miles per hour. This requires solar installers to test their panels and racking equipment to ensure they remain anchored to your roof in hurricane-level winds.

Most solar installers follow engineering guidelines the American Society of Civil Engineers (ASCE) set in their Minimum Design Loads standards book. While ASCE doesn't mandate a certain level of wind resistance, they outline a standard procedure for testing solar panels for a wind resistance rating. This ensures that solar panel installations nationwide are compared to a common standard. It is a good way to verify that your solar installer is putting their equipment through appropriate and accepted testing methods. Municipalities will often include ASCE 7-10, the wind-specific ASCE standard, as a part of their local building codes to ensure local solar installers abide by national building standards and calculations.

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