Solar systems are supposed to have a symbiotic relationship with nature, producing zero-emission energy harnessed from the sun itself. But sometimes animals can get too comfortable underneath panels, inside equipment or near photovoltaic arrays and cause problems that could result in expensive repairs. Small animals like mice or squirrels could chew through wiring, causing system malfunctions and possibly electrical fires. And removing nesting squirrels from under a rooftop array isn’t as easy as it sounds.
Precautionary product solutions can be installed to prevent animals from getting underneath rooftop solar panels, while still allowing proper airflow.
Conversely, certain ground-mount solar developers want some animals to be free to pass through solar sites in remote locations to reduce the site’s environmental impact. Animal-friendly fencing makes these crossings possible.
Critter control on rooftop solar
Flush-mount solar projects on pitched rooftops leave only a few inches of space between the panel and roof covering. Often it’s not enough room for even an installer to reach underneath, but small animals fit snugly and find safe shelter there. Nesting animals can cause additional stress to system wiring.
Covering the gap entirely would cut off necessary airflow underneath panels to maintain a proper system temperature, but there are products that block animal entry while still allowing the right amount of air to get through.
One option is SolaTrim, an aluminum critter guard that adheres to the border of rooftop solar arrays. Company founder Bob Smith previously worked for SolarCity and found there was a need in the market for solar pest abatement products after finding systems ruined by animals nesting beneath solar panels and chewing through wiring.
“Pests aren’t a problem until you get an infestation,” said Teresse Taylor, director of business development at SolaTrim. “Until [installers have] actually incurred the cost of a truck roll and new materials being sent out to mitigate pest infestation, it’s kind of an afterthought. It’s really important that everybody be aware of the fact that this is costing tens of thousands of dollars for some companies.”
SolaTrim was designed to work across all pitched rooftop racking. The critter guard comes in 48-in. by 6.75-, 5.5- or 4.5-in. rolls with a foam tape backing. It’s installed by wiping down the contact surface of the panel/racking with the provided acetone wipes, removing the foam tape backing and pressing the underlying adhesive to the solar panel frame. SolaTrim uses 3M’s VHB Tape, which should be applied at or above 40°F to properly bond with the racking. The company says it will remain attached in all climates.
If an installer needs to get underneath a panel after SolaTrim has already been installed, they must cut a section of SolaTrim and replace it with the leftover guard.
Omni Rooftop Systems carries Omni-Clip, a click-in-place device that has attachments for snow retention, lightning protection and pest abatement for residential solar systems. Founder Todd Kuchman also worked for SolarCity, and found many Colorado solar systems experienced issues related to the large pigeon and squirrel population in the state. He then devised a critter guard for rooftop arrays made of PVC piping and fencing.
Now, a few years and redesigns later, the Omni-Clip is a zinc alloy device that holds a galvanized fence around the perimeter of a rooftop array. The clip itself has two arms, both designed to slide and click onto the L-shaped lower lip of a solar panel frame.
Once the clips are in place, the fence is aligned and set into the exposed ends of the device, then a second piece slides in front of the fence to lock it into place. The standard height for the fencing that comes with Omni-Clip is 5 in., but larger sizes can be requested.
“If you have the right height and you don’t have to make any cuts or snips, for 99% of your application, you’re literally just lining up one of the grids,” Kuchman said. “It holds it in there for as long as you want, but if you ever had to service it, you simply undo the lock and the fence comes free and you can reuse everything a thousand times if you wanted to.”
Omni Rooftop Services offers installation services for the Omni-Clip, as well as pigeon and other pest evictions, where technicians will take a solar array apart and remove any animals and their nests.
“It’s a proactive measure to never have issues, noise, feces — everything,” Kuchman said. “There are some potential pitfalls to not having that protection on and the peace of mind to know you’re not going to have noisy neighbors living above you rent-free.”
Keeping ground-mount projects open to wildlife
Ground-mount solar systems tend to have fewer issues with animals than their rooftop counterparts. Rodents might nest in conduit boxes, birds sometimes defecate on panels and deer can get caught in boundary fencing, but “those were exceptions, rather than the rule,” said John Morrision, SVP of U.S. operations for solar developer Ecoplexus.
Commercial- and utility-scale solar projects can occupy hundreds of acres of land that animals used to freely traverse. Ecoplexus, Pine Gate Renewables and other solar developers are committed to keeping that land open to animals using permeable fencing.
“Quite honestly, we’re encouraging wildlife on the farms,” Morrison said. “The fencing that we put in, we’re making sure there are openings large enough for small animals to pass through.”
Morrison initiated more ecological practices into Ecoplexus’s solar projects, like replanting pollinator-friendly and native vegetation. The company started using wildlife-friendly fencing about three years ago. Certain brands of fencing have openings that permit small- to medium-sized species onto the site, while keeping larger animals that could damage equipment, like deer, coyotes and bears, away.
This type of fencing is fixed-knot wiring known as deer mesh. The bottom section of the fence has an extra set of vertical wires originally designed to keep baby deer from passing through. However, on solar sites, the fencing has been installed upside down, with the vertical wiring at the top, leaving larger openings on the bottom for smaller animals, while keeping larger ones out.
The animals that can access the site, like raccoons and foxes, are natural predators to small mammals that could nest in junction boxes and cause wiring issues. In theory, allowing these animals onsite would curb the rodent population in those areas, said Liz Kalies, director of science for The Nature Conservancy in North Carolina (TNC).
“Assuming clean energy is a good land use, why not go even further and let’s make this a habitat, let’s make this pollinator-friendly,” she said. “That’s where we started to work on this idea that these sites can be used by wildlife, instead of just being an area of turf grass, and everything stays out.”
TNC published a whitepaper for developers called “Principles of Low Impact Solar Siting and Design,” designating areas of the state with high biodiversity and asking solar companies to site projects elsewhere. In North Carolina alone, 40,000 acres are already occupied by solar arrays, with more projects in development. TNC, the North Carolina Pollinator Conservation Alliance and the North Carolina Fish and Wildlife Service’s Wildlife Resources Commission have been working with solar developers in the state to establish practices to ensure their solar projects are less ecologically disruptive.
“Things like unfenced wildlife corridors and other things that I think we’ll be experimenting with as solar continues to grow at the rate it’s growing, as facilities themselves start to become larger,” Kalies said. “There’s a lot of room to keep thinking about how to, on one hand, minimize impacts to wildlife and the environment, and on the other hand, use these places to create habitat and benefits to nature and to people.”