New technology keeps birds off big rooftop solar arrays

By Heath Waldorf, principal consultant, Bird Control Advisory

Imagine all your calculations for productivity, the value of that energy both in sellable power and Green Energy production credits (SRECs/TRECs) for the next 15 years. You’ve figured the number of panels that fit on the roof, the type of racking to secure it all, the quality of the inverters you plan to use, anticipated maintenance costs — everything all compiled as a report to present to an investor. You’ve got it? Good. Now imagine a flock of seagulls flying in through the open window and pooping all over that well-contrived document. 

Pest birds can cause the following problems for rooftop solar arrays:

Production drops by 10%, 20% or even 50%
Added costs for cleaning
Permanent damage from hot spots
Shattered panels from dropped debris
Workers unable to perform maintenance
Blocked drains and roof leaks

Bird problems are most often found geographically along the U.S. coastal areas and in the vicinity of the Great Lakes. Higher-risk locations include urban environments, those in migratory paths and those in proximity to smaller bodies of water including rivers, lakes and wetlands. 

Sometimes tied to water areas, food sources also include landfills or waste transfer stations, food manufacturers or even urban and commercial areas where garbage is plentiful. 

Birds are attracted to the warmth panels generate and often to the shelter beneath arrays which protects nests and fledglings (babies) from the elements. The panels warm up over the course of a day. Birds return to their evening roosts to find them nice and cozy. 

It is also often the case that birds are attracted to a particular site rather than the solar array. When investigating a rooftop location for potential development of a PV system, be weary of sites that have evidence of bird issues. While birds may avoid the site during the activity of construction/installation, they will quickly return to their long-standing residence once the flurry of activity has disappeared.

Methods to eliminate bird-related panel soiling

The cheap and easy methods simply do not work. Propane cannons, spinning shiny discs, iridescent streamers and audio systems (both ultrasonic and audible) all prove ineffective long term. 

For a long time, there was only solution for soaring birds in wide area flat roof situations — gullwire elevated grid systems that create an artificial ceiling over your rooftop using poles, hardware and either stainless steel cable or monofilament erected as a grid spaced anywhere from 10’ on center to 25’ on center. It is based on principles of bird behavior that soaring birds do not like to fly under things. Elevating the gullwire grid using poles adds accessibility and  negates trip hazards for maintenance. 

But a new option for protection is now available.

Laser technology has been used to scare migratory birds from fruit crops in the field and food production facilities for years. Only recently has the technology been applied to commercial roofs with solar arrays. 

A device that looks like a security camera is mounted in position over the affected area. Each custom-programmed unit patrols the roof with a green laser beam that birds see as a threat. Birds see the whole beam as a solid object coming toward them making them move to safety. The system operates in user-determined patterns at defined times to maximize effectiveness in response to bird behavior and for safety.

Lasers have been shown to reduce bird populations by up to 90%, silently and at a small fraction of the cost of a gullwire grid system. 

When should measures be implemented?

If your site already has bird issues, the time to take action is now! The longer a problem stands, the more challenging it is to displace a population. There are caveats when dealing with protected species with specific laws that dictate how and when remedies can be applied. In addition, you should not take action during the birds’ nesting season and raising their young. They become territorial and aggressive about their space and do not respond to threats meant to deter their presence. 

Birds should really be a key part of a project’s Soiling Mitigation Plan. In higher-risk areas, deploy a solution preventatively as an insurance policy against the risk of production drop and cleaning costs. The risk of equipment damage and cleaning costs rack up without a solution in place.

Could mitigation systems be built into your initial development and incorporated with the government incentives and tax rebates? It would be better to never have a bird problem in the first place — especially if the costs can be discounted. With fixed and limited time as an SREC/TREC producer, the power lost to bird droppings is not recoverable. 

Heath Waldorf is a Bird Mitigation Consultant with 20 years experience protecting buildings and structures from pest bird problems. He has worked on projects around the globe for major architects & engineers, real estate developers, power companies, and solar O&M firms. He can be reached through his website.