A roof-mounted photovoltaic (PV) installation can be the least expensive path to solar. But that doesn’t always mean it will be the solution that offers the greatest value. Borrego Solar has the experience—we’ve installed 50 megawatts of solar on rooftops across the U.S.—needed for large-scale solar projects.
“We’ve been working with Borrego Solar for awhile now to place the panels on the roof of these buildings in Hopkinton. The best part is it’s not costing us anything upfront. Boston Community Capital will own the solar power installation and Hopkinton will buy energy from them at a reduced rate. This is great for the town, and it’s actually a way to use green energy and get a discount on our electric rates without any upfront costs.”Rebecca Robak, Vice Chair of the School Committee, Town of Hopkinton, Massachusetts
During the initial site visit, a Borrego Solar project developer will assess the feasibility of your roof by considering a variety of factors for roof-mounted solar panels:
Roof Slope for a PV Array
The pitch of a roof impacts the minimum inter-row spacing required in order to avoid the shading from an adjacent string of solar panels. The more space required between module strings, the less usable square footage is available for solar. Depending on your location, the amount of shading from one row to another might occur at a time of day when energy production is so low that it’s actually better to use more panels because the overall energy generated will be higher when a small amount of shading occurs.
Assuming your roof is not flat, the slope azimuth should face anywhere from southwest to southeast. Solar can still be installed on roofs facing north, but the economics are less favorable.
Obstructions to Solar Panel Arrays
Our project developer will measure skylights, HVAC, and other miscellaneous equipment on your roof, as these physical impediments require customized designs. Fire and building codes often require a minimum amount of clear space around structures, referred to as a setback, which can limit the square footage available for the solar array.
It’s a common misconception that shading only comes from adjacent buildings and trees. However, stairwell enclosures, water tanks, large HVAC pads, and cell towers are some of the most common structures responsible for shading rooftop solar panels.
Some insurance carriers have specific coverage terms and conditions that can limit the type of solar you install, or your ability to install solar PV mounting structures altogether. Review insurance contracts with your insurance broker early on, so a remediation plan can be factored into the design, implementation, and long-term operation and maintenance of a roof-mounted solar project.
Roof Material & Warranties for Solar Racking Solutions
Some roof materials can be more costly and complicated to engineer racking solutions for. Others may require a specific type of mounting technology to comply with roof warranties. Any documentation you can provide during an initial site visit will help determine which applications will work best.
The ideal time to install a rooftop solar energy system is soon after a roof replacement. If maintained properly, your solar project will last 20-30 years or more. We recommend against removing the solar panel roof mounting equipment during the life of the project, as both removal and reinstallation are costly.
Structural Load of Solar PV Modules
Your roof must be strong enough to handle the weight of a proposed solar installation. If your site has not been retrofitted or upgraded recently, one of our professional in-house structural engineers will assess your property to determine if solar is feasible.
“It’s great to be able to do something so incredibly useful and green with the space on our rooftop, saving money on our electric bill is a bonus. We wanted to work with U.S.-based companies and use U.S.-made parts. We’re very pleased we were able to do that.”Ken Baker, CEO, New Age Industries
Borrego Solar specializes in bringing large-scale solar to commercial, industrial, and institutional customers in CA, NY, and MA. We also work with investor-owned and municipal utilities across the U.S. by providing development and EPC services as well as facilitating power purchase agreements (PPA) for utilities that wish to simply buy the solar power produced instead of owning the system.
To schedule a site feasibility study or speak to a member of our development team, contact us.
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