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Building Integrated Photovoltaics

Renewable energy brought down from the roof

Written by: Alexa Stone

Solar panels are most often seen on rooftops. That hasn’t changed. The difference today is the variety of materials and the variety of places where they can be installed.

Solar shingles

Tesla has been selling solar roof tiles since 2017. On homes, those tiles provide an attractive alternative to the common 60 or 72-cell solar panels while also filling-in for asphalt shingles.

Commercial and Industrial (C&I) panels, many with 96 or more cells each, are most often placed on factory roof space, Popular alternatives include the solar carports seen at the perimeter of parking lots, and the covered walkways leading into C&I buildings. Ground-mounted solar arrays are part of the landscape at many facilities.[1]

Those options are just the beginning!


The first solar cells, invented in 1883, contained selenium that was coated with a thin layer of gold. They were installed on a New York City rooftop the next year.[2]

After more than a century, a variety of materials have enabled more installations. Crystalline silicon cells are now most common. They may be contained in double-glass panels or formed into a thin film. Some, though crystalline, are amorphous. Others are dye sensitized.

Solar roof


Crystalline silicon also provides renewable energy for contemporary architecture, generating solar power through Building-Integrated Photovoltaics (BIPV). BIPV panels can be applied wherever there is sunlight. Some panels may be opaque, like shingles. Other installations require varied degrees of transparency: everything from curtain wall exteriors to skylights and windows.

Today, flexible modules with cells made of Copper Indium Gallium Selenide (CIGS) can be mounted directly onto the building envelope substrate.[3] They are designed to deliver power, even while protecting the building interior from wind and rain and allowing natural light to shine in. Exposure to direct light is optimal, but not required.

Cost considerations

As an emerging technology, BIPV brings technical and regulatory challenges. The products must meet requirements for building materials and for electrical materials. In some cases, building codes would have to be modified before installing it.

Until BIPV is manufactured in greater volume and more tradespeople are familiar with it, up-front costs of material and labor are likely to be high.[4]


[3] — CIGS cells