With the annual hurricane season having just started again, and parts of the U.S. experiencing one of the worse droughts in the nation’s history, people’s minds are focused on extreme weather events. We are now facing more intense once-in-a-lifetime storms on a regular basis due to climate change.
These disasters are the leading cause of power outages in the U.S., and Americans experience more outages than any other developed nation. The U.S. has seen a 67% increase in major outages from weather-related events since 2000, and our nation’s aging power system is ill equipped to keep up with this terrifying new normal of severe weather patterns.
To face this growing threat, we must build in a smarter, more sustainable way by incorporating home-based renewable power and storage systems that can withstand increasingly frequent climate hazards.
Pre- and Post-Storm Recovery
Many actions can be taken to prepare a home photovoltaic system for storm arrival and then, once passed, resume operations systematically.
- Perform a torque test of all fasteners.
- Power down all components by opening breakers, fuses, and switches.
- Remove debris and tie down loose material in and around arrays.
Post-storm measures before energizing the system:
- Dry and clean all electrical systems.
- Perform a torque test of fasteners.
- Test for electrical faults in all systems.
- Replace all damaged electrical systems before energizing.
On-site renewable energy systems such as rooftop solar with battery storage not only provide ongoing, non-polluting, affordable power that help tackle climate change, they prove remarkably resilient to severe weather. During natural disasters, such systems often sustain only minor damage and are able to stay online and provide power through emergencies while electric grids struggle to get back into service.
Keeping power on is not just an issue of comfort and convenience – it is a matter of life and death. For instance, carbon monoxide poisoning from unsafe operation of backup home generators is one of the leading causes of deaths from power outages. In addition, prolonged power outages are a threat for the safe storage of refrigerated medications and the survival of individuals that require use of electricity-dependent durable medical equipment. Being left without air conditioning in the extreme heat, or without heating in the extreme cold, can also lead to deadly consequences.
Good operational and maintenance practices are an important factor in the survivability of home solar systems in severe weather. For existing systems, owners can implement measures (pre- and post-storm) that can greatly minimize equipment damage and recovery time.
Fore those purchasing a new photovoltaic system or who are upgrading an existing system, there are some important design and construction specifications that greatly increase the survivability of a solar system from a severe weather event.
Most solar racking systems, the frame on which solar panels attach, provide two frame rails for module mounting. Consider using a three-frame rail system to provide greater rigidity and support to reduce bending and twisting. Also look for racking systems with closed-form (tubular) frames as they have low drag coefficients which have proven to be better in severe weather situations than open shaped “C” and hat channels.
When choosing locking hardware, avoid split washers, nylon nuts (nylocks), serrated-flanged nuts, and double-nutting, as these technologies are proven ineffective in severe weather. Look for wedge lock washers, which are one example of a highly effective, affordable class of locking hardware.
Module clamping fasteners are also a cause of equipment loss from hurricanes. Nearly all racking manufacturers use clamps to attach modules to sub-framing. Clamping fasteners allow for fast assembly, generally are not adequate as they can be easily overcome in high winds. In addition, the loss of one module in a row often causes loss to all adjoining modules, since one clamping fastener is shared between two modules. Instead of using clamping fasteners, consider through-bolting modules with a locking fastener tightened to a specified torque rating.
It is possible to increase resilience against the impacts of climate change, reduce the emissions of greenhouse gases, and lower energy costs. These are not actions for the future, but solutions for the present. However, they are only solutions if we each take steps to achieve them.
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