As anxious Floridians carefully track the path of Hurricane Irma, we have been getting a lot of questions about hurricane preparations for those who have solar energy systems on their home or business. Most of these questions relate to the durability of solar panels and what actions those who have solar power should take in advance of and after the storm. We hope to answer most or all of those questions here!
Today’s solar panels are designed and tested to withstand high-velocity hurricane winds. Current wind codes are 150mph (north Sarasota County) or 160mph (south Sarasota County) – wind force resistance in solar panels is usually measured in Pascals, a unit of pressure. Most panels are rated to 2,400 Pascals of uplift force (just over 50 pounds per square foot) with a standard two rail mounting system. That means a single panel can take a load of more than 900lbs of uplift before being destroyed.
The dynamics of wind around a building are more complex than can be described in a blog post but, suffice it to say, the edges of a roof are subject to higher wind speeds and turbulence (and therefore higher pressures), and corners even more than that, so we design the attachment layout to meet the varying wind loads around the roof.
All of the loads on the panels are transferred to the attachments, then into the roof system itself, so at each step in the chain we have to ensure the components and methods are strong enough to meet the requirements. Another important issue is that panels that are attached flush to an existing roof system are considered to not add uplift to that roof, which makes sense as long as the panels are less than about 8 inches off the roof deck.
It’s important to understand that a well-installed solar PV system can actually make your roof system stronger. Each rail of the racking system is essentially a 2×4 running perpendicular to the trusses, helping to distribute turbulent/vortex loads from the edges and corners of the roof into the center of the roof. There is variation from site to site, and it’s not a guarantee, but a properly engineered and installed solar array really can increase the strength of the overall roof system.
Flying debris may damage the PV modules or electrical wiring but debris is just as likely to damage the roof as the solar array. Water damage is possible but is not particular to solar – it affects any building subject to shearing winds and any penetrations to your roof.
If utility power fails, your inverter(s) will cease to produce power and your system will shut down automatically. For an added layer of safety, you may wish to shut your system off manually by turning off the main photovoltaic disconnect switch(es). This switch should be near you utility meter. If not, a sign near the meter should show its location. Large systems may have multiple disconnects. Simply move the switch from the “on” to “off” position. It is not as easy as flipping a light switch but has the same effect.
In the event of a direct hit, you might consider turning off all power to the house, which would also shut down the solar PV. After the storm, if you did disconnect
your system, you will need to flip the disconnect switch back on.
THIS IS VERY IMPORTANT: If any PV modules or wires are damaged, do not handle the materials. A damaged PV system can still generate electricity – treat damaged PV modules like live utility wires. You may want to have Brilliant Harvest conduct an inspection before re-engaging your system, particularly if there was any serious wind, flooding, or roof damage. There is a fee for a site visit – call us for more information or to make an appointment.
After the storm
If your PV system has a web-based monitoring system, after the system has been restored, check to see that the electricity output has not changed significantly from prior to the storm. If it has, you may want to give us a call to investigate what the issue might be.
Most insurance policies cover solar power systems. Since the systems are permitted and inspected, they are considered a “permanent” part of the structure and so are included in your overall insurance coverage. The only time this can be an issue is if the home is underinsured. In that case, a total loss would not cover the cost to replace everything.
If you have storm damage to any solar energy product, notify your insurance company and then call us for a repair estimate. Insurance companies may not be qualified to assess the cost of repair for solar energy products – it is important that you contact a professional to assess the damage.
The solar industry has recovered quickly after past storms, and many systems in the direct path of storms have held up without any damage whatsoever. We encourage you to prepare calmly and wisely for the storm and wish you safety and comfort until Irma has passed.