Can you tell which roof has hidden solar panels?

Would you believe all of them? Meet integrated rooftop solar.

In the dark of winter, when days are shortest, those of us in northern climes long for the sun. What better time to think about capturing and storing that sun’s energy? Solar electric power has been around for decades, and advances in the technology keep making it more efficient and practical. But for many, the desire to cut the household carbon footprint is tempered by aesthetic concerns. Rooftop solar panels don’t exactly look pretty, unless you’re going for Wall-E-meets-Windows chic.

Enter Tesla Motors. Not just a car company anymore, Tesla recently acquired SolarCity, the nation’s largest solar service provider. And the combo’s flagship product? A solar roof. It’s an array of photovoltaic panels, custom installed, that looks pretty much just like an ordinary roof. It will come in styles including slate and Tuscan tile. And with the star power of CEO Elon Musk, this product with curb appeal just might do for solar rooftop panels what Tesla has done for electric cars—make them cool. All part of the company’s professed mission: to accelerate the world’s transition to sustainable energy.

Musk unveiled the roof last fall at a shareholders’ meeting held in Universal Studios’ backlot. Investors gathered on a street that has served as the generic suburban setting for TV fare from Leave it to Beaver to Desperate Housewives. To hit the market some time this year, the panels are printed with the shingle-looking designs in a process called hydrographic coloring. They’re made of exceptionally durable tempered quartz glass. See how the material holds up compared to conventional roofing tiles:

Hidden underneath the glass are photovoltaic cells that will harvest the sun’s rays, feeding the energy to Tesla’s Powerwall 2 battery. The company says the battery can power an average two-bedroom home for a full day.

“It looks viable,” said Josh Rollins, LEED AP BD+C. “If it is, it’s a total game-changer.” A senior manager of marketing at Suffolk Construction, Rollins is also a leading member of the company’s Green Committee. “Elon Musk reminds me a bit of Steve Jobs in the way that he hypes his products, but this one is particularly exciting for anyone who’s passionate about reducing their carbon footprint,” Rollins said.

Musk’s presentation lacked some details, but flurries of informed speculation on the part of industry professionals help fill in the blanks. The biggest question to many is the roof’s cost. Musk says Tesla’s system will be cheaper than a traditional roof, when you factor in projected savings on your utility bill over the Tesla roof’s lifetime (50 years).

tesla-solar-roof-2

Image courtesy of Tesla

How could Tesla achieve that lower price tag? For one thing, the quartz glass is a fifth as heavy as typical roofing materials; meaning lower shipping costs. For another, Musk hinted that he’ll cut out middlemen in the current roofing supply chain, with Tesla doing the installations itself.

All that said, the cost of a traditional roof plus the cost of grid electricity is quite steep, so even a figure smaller than that sum will likely still be large. Consumer Reports put the total as high as $70,000, too much for many homeowners to bear up front. Will the company offer financing? What if a homeowner defaults on the loan? Will Tesla rip the roof off and take it back? Unclear as of yet.

But Tesla’s entry into the residential solar market can only be a good thing if you’re rooting for the environment. As many as five million roofs per year need to be replaced. If you need a new roof anyway, why not make it one that will save you money on utilities? At least a certain segment of homeowners will be able to afford the premium Tesla product. And for those who can’t, Tesla’s announcement should bring more attention to other, relatively affordable integrated rooftop solar products.

That’s right, Tesla has competitors in this niche—companies like SunTegra and CertainTeed. Though none of their solar products are quite as invisible as Tesla’s, many are pretty darn unobtrusive, especially compared to the standard rack-mounted panels. (Check out the examples below.) These companies welcome the new publicity. “I have to agree with Elon Musk: the future for roof integrated solar is bright,” wrote SunTegra CEO Oliver Koehler in a trade publication. “It’s going to be an exciting next couple of years.”

certainteed_apollo-west20coast20houselarge

Image courtesy of CertainTeed

suntegra_stifton3-min

Image courtesy of SunTegra

What we really look forward to is learning whether the integrated technology can be scaled up to apartment complexes, and perhaps to even bigger projects—maybe even high-rises. After all, said Rollins, “Why stop at the roof?” Rollins recalled a previous Build Smart blog post about harnessing solar energy with windows, something a skyscraper in Australia plans to do. “Why not cover the skin of the entire building in solar panels? That’s another whole surface area that could be generating electricity,” Rollins said.

Perhaps we can yet break our addiction to supply-limited fossil fuels, thanks in part to visionaries such as Musk. Heck, the last time a Tesla release made us this optimistic, it was an awesome late-1980s power ballad. Here’s to solar finding a way.

This post was written by Suffolk Construction’s Content Writer Patrick L. Kennedy. If you have questions, Patrick can be reached at PKennedy@suffolk.com. You can connect with him on LinkedIn here or follow him on Twitter at @PK_Build_Smart.

A building’s skin and bones—literally? The coming world of engineered living materials

When lightning strikes, a tree can often repair the damage by generating another layer of bark to cover the gash. But if that same bolt from above lashes a wood-frame house instead, call the remodelers. Even though the house’s exterior walls are essentially made of trees, the material lost its adaptive quality when lumberjacks felled those mighty pines or oaks.

In the words of scientist Justin Gallivan of the U.S. Defense Advanced Research Projects Agency (DARPA), wood is “rendered inert” when a tree is chopped down. That neutralizes all the advantages of a living material. In their natural state, trees react and adapt to wounds and the weather. So do coral reefs—not to mention your own skin.

What if living materials, with those same self-healing properties, could be grown artificially to the size and strength required to construct a house? Or a skyscraper? Is that possible? That’s what DARPA wants to find out. The agency is soliciting research proposals aimed at the creation of what it calls “engineered living materials (ELM).”

elm_composite

DARPA envisions walls that fix themselves, non-fading surfaces, and driveways that absorb oil spills without a trace. (Source: DARPA)

“Imagine that instead of shipping finished materials, we can ship precursors and rapidly grow them on site using local resources,” Gallivan said to the press in August when announcing the ELM program. “And, since the materials will be alive, they will be able to respond to changes in their environment and heal themselves in response to damage.”

Today, a building’s envelope is often called its “skin,” while the steel frame of a building is known as its skeletal structure, or even its “bones.” In DARPA’s imagined future, these terms will cease to be merely rhetorical. And the sustainability benefits of bio-building might be substantial, when you consider the carbon emissions generated in the production of conventional materials such as concrete.

But DARPA didn’t pull this sci-fi-sounding concept out of thin air. Biochemists and engineers around the globe are already tinkering with limited forms of biomimetic (or life-imitating) materials, as you’ll see below. Gallivan’s vision of self-healing living walls is perhaps the logical extension of these various technologies, and the ELM program might prove the catalyst needed for skin-and-bone to replace brick-and-mortar.

Bacteria brickyard

One inspiration for the ELM program is a start-up that grows bricks in a lab. Yes, grows. The idea occurred to architect Ginger Dosier when she learned that coral polyps—tiny marine animals—create the hard, rocklike substance sandstone naturally. She co-founded the company, bioMASON, with her husband, Michael—like her, an architect and a self-taught scientist. (They have help from a staff of college-taught scientists.)

bio-bricks-image

The lab-grown bricks. (Source: bioMASON)

In their lab in North Carolina’s Research Triangle, the bioMASON team places sand into molds and injects it with trillions of microorganisms (Sporosarcina pasteurii, if you must know), which they feed water and a calcium solution. The bacteria bind with the grains of sand, generating a natural cement that becomes heavy and hardens. The bricks are ready in two to five days.

Compare that with the way traditional bricks are manufactured, by digging up clay (which could be better put to use in agricultural soil) and firing it in a kiln at 2,000 degrees for three to five days. This process uses up lots of fuel and releases carbon dioxide into the atmosphere—800 million tons of it per year, by some estimates. Keep in mind, brick is still the most common building material worldwide, with Asia alone making 1.2 trillion bricks a year.

According to Acorn Innovestments, which provided bioMASON with seed funds, third-party testing determined that the bio-bricks have a strength comparable to traditional masonry, though for now, the start-up is only selling the bricks for use in paving. The bioMASON lab can produce 1,500 bricks a week, and they’re moving next month to a larger facility that will enable them to make 5,000 bricks every two days.

But the Dosiers hope to truly make an impact by shipping the bacteria solution—just one hand-held vial can make 500 bricks—across the globe to builders who can mix it with local sand, whether from nearby deserts (looking at you, Los Angeles) or quarries. Continue Reading ›