The solar revolution may be televised, but it’ll be hard to see. In the near future, the age of the solar panel may give way to the age of the solar shingle, solar window, solar siding, solar paint and all things building integrated. BIPV - Building Integrated Photovoltaics - is the heir apparent of the solar energy movement—the little brother set to grow up in a big way. Whereas conventional, aluminum-framed solar panels are more of an addition to the average home, future solar components will be key ingredients in the recipe of home building. They won’t be on your roof, they’ll be your roof. That, in essence, is what makes BIPV so cool, if still a tad underdeveloped. Already, solar shingles (mostly solar roof tiles) are lining many rooftops, keeping the rain out while taking the sunshine in. Companies like Nanosolar are printing solar cells onto thin rolls of “foil.” Researchers the world over are working to commercialize spray-on solar cells that could one day become the most energetic paint you’ll ever buy. And it’s all being done with less material, in less time and at a lower cost than conventional silicon-based solar panels.
Solar shingles are solar panels incognito. Instead of mounting on your roof, they become your roof or integrate seamlessly with the existing roof shingles. In many cases, they can be stapled to the sub-roofing the same as an ordinary shingle. On average, shingles are about 12 inches wide by seven feet long. There are also solar roof tiles that integrate well with mission-style housing common in the sunny Southwest. Solar shingles, like most thin-film BIPV products currently on the market, are less efficient than silicon solar panels. But, again like other BIPV innovations, are a burgeoning work in progress.
The most fantastic possibility for BIPV lies in the minuscule size of the solar cells. They can be so small—on the nanoscale in fact—that they can be deposited into liquids and sprayed onto surfaces. BIPV leader Nanosolar is using just such a solution (they call it “ink”) to create their rolls of bendable solar cells. Someday, when researchers tackle the problem of durability and efficiency (among others), spray-on cells could be incorporated into paint and product coatings. In other words, your new exterior siding, sheet metal roofing or windows could come made with electricity-producing solar cells.
PIPV: People-Integrated Photovoltaics
Worth mentioning is the fact that the same nanotechnology that promises more building-integrated possibilities than we can imagine will also make it possible for humans to wear solar cells. Seriously, researchers in laboratories around the world have scaled down solar cell production so much that cells can actually be interwoven into fabrics. That means that one day, your jacket or sweater could charge your cell phone, MP3 player or eBook as you walk down the street absentmindedly shopping through windows equipped with BIPV cells powering the very storefront through which your eyes meander.
One Day, Some Day, What a Day
You may have noticed the words “someday” or “one day” used quite a bit in this post. That’s not to imply that these technologies don’t exist, because they do, but they still have room to grow before that window shopping scenario can become an everyday reality. Issues like durability, conversion efficiency, manufacturing and commercialization still need to be worked out. For that reason, conventional silicon wafer solar cells continue to control better than 80 percent of the market today, but that lopsidedness is starting to give way. US solar giant First Solar is leading the thin-film revolution, taking the first major step down a road that will undoubtedly lead to the commercialization of the products mentioned here and many more.
BIPV panels are lauded for their aesthetic value, their pleasant invisibility compared to their bulkier forbears, but that uncanny ability to integrate transcends simply making a roof more nondescript. What really makes BIPV so bodacious and incredible is the wide range of integration possible. Just about any part of the outer shell of a home or building (and especially skyscraper) could be a solar power producer. Heck, even you and I will someday, one day strut around town making electricity out of sunlight…and what a day that will be.