John Van Winkle, a senior member of the engineering department at mounting manufacturer Schletter, recently discussed top O&M tips for solar mounting systems, both on rooftops and the ground, during a Solar Power World webinar. We have outlined his points below. While this is not a complete list of checks necessary to ensure the long-term success of solar projects, it is a sampling of information provided during the webinar, available here, and a good starting point for O&M teams.
Rooftops
- Seismic Events. If there’s been an earthquake, or even a tremor, technicians should immediately check rooftop solar arrays for any sign of movement. A displaced system can transfer loads on the rooftop, perhaps stressing the underlying support. Moved systems can also stress or overload wires and other components.
- Water Pooling. Solar systems can place substantial weight in a concentrated point on a roof, and that can cause an indent in roofing over time – a place for water to pool. Any time water pools around metallic components, rubber support pads or concrete blocks, action is necessary. These products are not designed to be submerged in water for extended periods and could prematurely corrode.
- Copper vs. Aluminum. Most rooftop systems are comprised of aluminum parts. If copper wire touches aluminum, technicians will find corroded components and failed connections. Corrosion can also disconnect the equipment ground.
- Fire Hazards. Any time a change or modification to a system is made, it is potentially negating the installed fire rating of the system. It’s important to pay attention to ratings when performing maintenance or repairing components.
- Debris. As a system ages, debris will gather under the racking. Birds will nest under it, too. This is a fire hazard. Debris can also lead to corrosion. Pest droppings, plant debris and organic matter will prematurely degrade aluminum and steel components. Debris will also lead to water ponding on the roof, preventing water from flowing underneath a racking system.
The Ground
- Long-term corrosion. Technicians should look for any signs of long-term water stagnation around the support system. Also keep an eye out for vegetation or pest infestations underneath the system that are either entangling it or causing debris to pile up on any metallic or electrical component. Debris will degrade and increase the rate of corrosion on a system.
- Exposed wires. Loose or exposed wires routed along the length of a racking system can cause an electrical short. They are also vulnerable to rodents.
- Settling. Improperly compacted soil can lead to ground movement, or settling, and can stress the structure of a solar array. After a heavy rain, or a couple years of operation, technicians may notice settling around conduit lines going up posts or around the foundations themselves. Settling can be addressed by supporting the settled area with fill and properly compacting it.
- Ponding. Often due to the improper grading of a project site, saturated soil will corrode steel, even with galvanized coating, much more rapidly than dry soil. As often happens in the industry, if another project is being installed adjacent to an existing one, it’s important to ensure no additional water is flowing to the new project site. SPW