Roofing systems are valuable assets designed to perform a critical function — protect the top of a building. A building’s roof may not have been designed to become the permanent platform for a heavy photovoltaic (PV) system. But throughout the world, rooftops are being converted into solar power systems as building owners, energy advisory agencies and other decision-makers attempt to capitalize on the environmental and financial benefits of installing a rooftop PV system.
PV systems can be a valuable asset to virtually any building if the correct factors are evaluated. A comprehensive rooftop PV installation should minimize building owners’ and large energy users’ risk while maximizing their return on investment. Therefore, those interested in pursuing these renewable options should look to experts to select the ideal system for their buildings.
When considering PV, it is crucial to first carefully evaluate the integrity of the existing roofing system. A typical rooftop PV investment is based on a 25-year financial projection. Therefore, the roof must be capable of sustaining an installation for at least that long in order to maximize returns.
Those considering a rooftop PV system should also remember to ask the following questions:
- If you are a building owner, did you engage a roofing professional to ensure your roof is properly designed to sustain a heavy, expensive and long-lasting PV installation?
- Is the current or new roofing system suitable for traffic, weight and at least 25 years of performance of today’s PV systems?
- Will the maintenance or eventual replacement of the roofing system disrupt the power output of the PV?
- Who is responsible for paying to remove and reinstall a PV system during roof repair?
Integrated PV systems can be added to new cool roofing installations to create programs aimed at establishing concurrent lifecycles between roofing and PV systems. A “cool roof” reflects and emits the sun’s heat back to the sky instead of transferring it to a building below, according to the Cool Roof Rating Council, an organization created to develop credible methods for evaluating the integrity of these roofing options. A roof’s “coolness,” the council states, is measured by two properties: solar reflectance and thermal emittance. By syncing the lifespans of an integrated PV system and cool roofing installation, building owners can maximize renewable energy production and financial rewards.
Rooftop solar is purchased based on a calculated return on investment, ROI. The expense of disassembling and moving a solar array for roof maintenance or replacement can destroy building owners’ anticipated solar ROI. It is, therefore, crucial to check with building products manufacturers on ways to protect these investments, such as long-term warranties.
Putting Systems to Work
Firestone Building Products received a clean energy grant from the Connecticut Clean Energy Finance and Investment Authority in 2011 to update the roofing system and add PV panels to its polyiso manufacturing plant located in Bristol, Conn. With the funding, the company gave owners the choice of a variety of heavy-duty roofing systems, including: TPO, EPDM, SBS Modified Bitumen and standing seam panel metal systems.
An integrated fully adhered EPDM membrane was installed over ½-inch cover board with a thermal layer of ISO insulation. Four separate PV systems — each representing a specific PV technology or application — were then installed above the roof membrane and used to create clean, renewable energy for the facility, offsetting its electrical grid usage or consumption and leading to significant cost savings.
In addition to the state’s clean energy grant the installation also qualified for federal incentives in 2012 amounting to 30 percent off the installed PV system cost. This was part of the U.S. Treasury Department 1603 Program for Payments of Specified Energy Property in Lieu of Tax Credits. The PV system was commissioned in June 2013, and the overall system is expected to demonstrate a very attractive return on investment with a three- to four-year payback. That timeline takes into consideration the high cost of electricity in the area and the various incentives available to help offset the installed system costs.
The Bristol facility’s comprehensive program is covered by a 30-year warranty, which protects against leaks, incidental punctures, up to two inches of hail damage and 100 mph wind gusts.
The environmental benefits and cost savings calculated by the Bristol plant serve as a real-life success story for those pursuing and embracing renewable energy, further reinforcing the relevance of PV and green roofing products.
Lead image: Solar panels via Shutterstock