Habitat for Humanity
Photovoltaic Shingles
Behind the Scenes - Habitat for Humanity
Deane Evans from PATH (the Partnership for the Advancement of Technology in Housing) and Dr. Ren Anderson of the National Renewable Energy Laboratory joined Bob for the installation of the photovoltaic shingles on the shed roof.
Unlike the cumbersome and often obtrusive solar panels of a decade ago, these photovoltaic (PV) modules (which convert sunlight into electricity) are integrated right into roofing materials resulting in a solar system that is difficult to notice on the roof but has benefits that are hard to miss. Once installed, PV roofing produces free electricity from sunlight that can power certain home functions (as in the Yonkers project) or supply the entire electricity needs of a home and eliminate the need for connection to the utility company.
Photovoltaic roofing replaces existing roofing materials such as asphalt shingles, standing seam metal roofing, and slate or concrete tiles. Most residential PV systems consist of a PV module (i.e. photovoltaic shingles) or building material that produces electrical current, battery storage, and an inverter and wiring to convert PV current (DC) from sunlight to standard household current (AC) and distribute it directly to the building. Small home PV systems are commonly attached directly to appliances or lighting systems, while larger systems can be stand-alone and supply all power for the home.
PV systems can also be used in conjunction with utility-supplied power. Excess power produced during daylight hours can be fed back into the utility's lines, while electricity can be drawn into the home when demand is greater than can be supplied by the PV roofing.
PV roofing installations require a portion of the roof to be exposed to direct sunlight—in North America, for example, the southern roof must be unshaded. Depending on the PV roofing product, they can be installed by either a roofing professional, an electrician, or both.
The solar electric roofing products are configured in series or parallel on the roof deck to form an array. The array is then used in combination with conventional roofing products. The flexible thin-film shingle blends in to the roofing pattern of traditional asphalt shingles.
PV roofing products provide environmental benefits because they do not produce pollution or carbon dioxide emissions like fossil fuel-based utility power. They are also more attractive than many other solar systems, which increases consumer acceptance.
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