Building-integrated thin-film PV is the wave of the future.
By now, everyone knows what a photovoltaic system looks like: an array of flat glass-fronted panels on a rooftop or on slanting mounts at ground level, right? Well, yes. But a group of new technologies known as thin-film are changing that.
Conventional PV cells are made of silicon crystals, so they’re rigid. Thin-film cells are much smaller. This allows the material that contains them to be flexible and sometimes almost completely transparent. They’re not yet as efficient as crystal cells, but they can be used in many more ways. Some of these are even manufactured into the materials of the building itself.
Thin-film rooftops: Watch where you tread.
Thin-film PV may be used in glass-fronted panels organized in arrays. It can also be rolled out and laid like tarpaper in polymer sheets that can cover entire rooftops. It typically looks like long rows of shiny rectangles. Harder to recognize on rooftops are another recent innovation: thin-film technology applied to individual shingles and tiles.
Particularly on new buildings, you’ll want to know if these materials are being used. They are durable, but shouldn’t be walked on. And all the same precautions about cables, conduits, inverters and other equipment apply.
PV panes: Handle with care.
Another thin-film application is in multi-paned windows, glass canopies or curtain walls. The PV film is sandwiched between sheets of glass, which are connected together with hair-fine wires that run through the frame and then to a combiner. Although the actual cells in these transparent glass arrays are well protected, the inner wiring is relatively fragile. If you’re working near thin-film in glass, make sure ladders or equipment don’t bump into the surfaces.
If you work around newer homes or commercial buildings, look out for thin-film PV on rooftops and in glass windows or walls.