What’s on YOUR Roof?  Put a Green-Energy Resource Over Your Head

Quick reminder: CUB is celebrating its 25th Anniversary this year, and we’re throwing a party! On November 14, 2009, we invite you to come celebrate CUB’s accomplishments and support our future endeavors. You can download and return a reply card with your payment information, or submit your payment online by clicking here. Please return a card or pay online so we know you’re coming! We look forward to seeing you there.

And now on to our regularly scheduled post:

How, oh how, to solve global warming and still meet our energy needs? A lot of different ideas have been touted as solutions to global warming and green energy production, and even more ideas are coming out to solve the problems that existing “solutions” have presented. For example, scientists are working on efficient ways to get biofuel from algae so that farm land can return to producing food rather than corn for ethanol use, and others are experimenting on making hydrogen storage tanks out of chicken feathers as a way to make hydrogen-powered vehicles economical. The beginning of the Age of Green Energy can seem like a strange time.

However, not all ideas are as incredible; recent plans have focused on bringing energy sources home. To substitute energy from coal and natural gas, many green energy developers and policy makers are focusing on utilizing previously ignored space that nearly every homeowner, business owner, and municipality has control over: their roofs.  Roofs are natural homes for solar panels, but that’s not the only thing green companies are installing on roofs these days. U.S. Energy Secretary Steven Chu has been advocating for “white” roofs, roofs all over the country are sprouting vegetation, and some companies are experimenting with putting wind turbines on skyscrapers!

Let’s start with solar. Celebrities from Bill Nye (the Science Guy) to Brad Pitt have installed solar panels on their roofs and encourage people to follow their lead. Local policy makers are willing to help them do it, passing more and more legislation that promotes small-scale solar projects. Feed-in tariffs that pay home and business owners for the electricity their units generate are growing in legislative popularity. After Germany’s initial success with the policy, other nations and U.S. states (including Oregon, with the passage of HB 3039 this past session, establishing a feed-in tariff pilot project) have followed suit.

Solar panels generate energy, but the roofs they occupy may still contribute to global warming. Dark roofs absorb up to 90% of the sun’s heat energy, causing urban “heat islands” and generally contribute to a warmer climate. Energy Secretary Steven Chu has a solution to this: “Make it white,” he told the audience of The Daily Show in July 2009. Roofs that are painted white or have a white covering absorb as little as 10 to 15 percent of the sun’s heat energy, leading to their alternative nickname, “cool roofs.” Keeping a building cool with a white roof can reduce its air-conditioning-related electricity costs by 20 percent or more in hot, sunny weather. For this reason, Wal-Mart has been equipping its stores with white roofs for a decade at new Wal-Mart stores—more than 75 percent of the chain’s 4,268 outlets in the United States have them, reports the New York Times. The Times article also points out that houses in hot climates have been whitewashed for centuries, and notes that California, Florida and Georgia have recently adopted building codes that encourage white roofs for commercial buildings.

Some critics of white roofs worry that reflection of the sun’s rays may actually increase energy usage in cooler, wetter climates, such as Oregon experiences most of the year. Luckily, there is an alternative energy efficiency roof trend: literally make your roof green by growing plants on it. Green roofs, or ecoroofs, are “vegetated roof systems,” and they come in all landscaping styles and sizes. The main purpose is to use a natural system to better manage storm water (which is another eco-challenge that is more relevant to Oregon than sunny California, where white roofs make sense), but they can also make buildings more energy efficient by moderating building temperature, as white roofs do. As with all energy efficiency, this decreases energy bills, limits the emissions of greenhouse gasses, and constitutes the least-cost energy option available. A number of prominent Portland roofs are already green, including the Portland Building downtown, the Multnomah County Building, and up-scale apartment buildings on the river near OHSU.

Roofs seem like natural homes for solar panels, white covering, and even plants, but wind turbines? Maybe. A new mixed-use tower in downtown Portland, christened Indigo @ Twelve West, features four wind turbines on its 22-story-high roof. Although they will only contribute about 1% of the building’s total energy needs, the downtown turbines are an experiment and a gesture. Its “more about generating knowledge than electricity,” developer John Breshears told a New York Times’ Green Inc blogger. In addition to generating interest, Green Inc. reports that “the turbines will provide much needed data on the efficacy of urban rooftop wind farming,” which still faces a number of challenges, including the “prohibitive size and weight needed to generate cost-effective power” and annoying vibrations caused by the turbines’ spinning blades that can shake a building’s frame. The Boston Museum of Science also launched a rooftop wind “laboratory” earlier this summer. Wind may never be reasonable in a residential setting, though it may yet find a home in cities.

Even if none of the above is ON your roof, good insulation should be UNDER it. Weatherizing your home decreases the energy needed to cool it in the summer and heat it in the winter. Not only does it save you money on energy bills, but the GHG emissions from your house also decrease. Incentives are currently available in Portland and are soon to be available throughout the state. For more information on weatherization and energy efficiency, read our July 24, 2009 entry or see the related links on that page. You may never look at your roof the same way again.

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