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By Peter Fairley

The disappearing act

The ultimate challenge to integrating PV technology is accommodating those customers, or neighbors, who are holdouts against the renewable-power look. Solar-power NIMBYs are often particularly vocal in residential areas. In California, the state’s legislative assembly saw fit to expand the state’s Solar Rights Act last year, seeking to quash antisolar building codes and bylaws across the state that were largely put in place because of aesthetic concerns. Even in San Francisco, a city that has embraced solar power, residential architects must proceed with caution to avoid costly, time-consuming disputes with neighbors. Richard Parker, AIA, a partner at 450 Architects, says 90 percent of his firm’s projects last year included PV, but not all are visible from the street. For example, he designed a parapet to hide a solar installation atop a home in Noe Valley that is surrounded by Arts-and-Crafts-style houses. “We’re going to be generating a ton of power, and you’re not even going to be able to see it,” says Parker.

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Another solution is to switch to products that incorporate PVs within building materials. This is where thin-film products come in. When viewed from outside, thin films have a uniform color, usually black or gray; they can also be produced on flexible substrates like plastic, making them easier to apply to metal roofing and fiberglass-reinforced tiles. Architects agree that opaque, thin-film PV panels have a role to play in some buildings. “Where you have an all-glass building and you’re paying for the glass already, I think there’s a logic to [using] it,” says Pelli.

What thin films offer in stealth is offset, unfortunately, in efficiency. They produce as little as one-third the power as conventional crystalline PV cells—a serious liability given that their installed costs are only marginally lower than that of crystalline cells. Still, especially for large roof systems, their economics can make sense.

A leading proponent of using thin-film technology atop buildings is Southern California Roofing, the nation’s fifth-largest roofer. In 2003, two of the firm’s principals established a separate start-up company called Solar Integrated Technologies in Los Angeles, to bond charcoal-colored thin-film PV to metal and membrane roofing. The new product is both a roof and a power-generating system. “We turn a liability into a producing asset,” says Richard Schoen, FAIA, executive vice president for both firms who teaches sustainable architecture and community planning at UCLA. “We aren’t on the roof,” says Schoen, “we are the roof.”

Schoen has seen a rise in interest in thin-film technology from architects, and says his firm has had inquiries about designs ranging from solar sails to tensile structures. In other words, thin films, like their crystalline predecessors, are themselves begetting exciting and highly visible solar structures, as Scarpa and fellow Pugh + Scarpa partner Angela Brooks are realizing in a transformation of the Venice, California, bungalow they share. A solar canopy comprised of thin-film panels will wrap a 1,200-square-foot extension of their 700-square-foot home. They call the addition the Solar Umbrella, recalling Paul Rudolph’s Umbrella House and Heyward Apartments of 1953. The panels of amorphous silicon will meet all of the Solar Umbrella’s electrical demand, while screening the house from intense southern sunlight. “Solar panels, conventionally relegated to a one-dimensional utilitarian application, define envelope, provide shelter, and establish a distinctive architectural expression,” the partners write in a summary of the project.

The panels look like tinted black glass from the outside, but from below, says Scarpa, incident light is filtered as through a prism, resulting in rainbows of illumination that “enliven the more permanent and fixed elements of the design,” say the designers.

That’s certainly a far cry from tacking solar panels to the roof.