Up on the Roof

Opportunity is in the eye of the beholder.

Flying low over Boston University, some might see a congested Commonwealth Avenue bordered by a multitude of buildings and parking lots. Others might see acre upon acre of available space, where gardens could grow, energy could be produced, and scientific theories could be put to the test.

Open space on campus? There’s plenty of it — it’s just up there, on the roof.

Nathan Phillips, a College of Arts & Sciences associate professor of geography and environment and director of the Center for Energy and Environmental Studies, regards rooftops as an unexplored frontier, where with some creative thinking much can be done in the name of research and sustainability.

“It doesn’t mean redoing the entire roof infrastructure,” says Phillips. “It can mean some very modest additions.” Phillips envisions starting with the “lowest hanging fruit,” like rooftop gardens of potted plants, before moving to more complex projects, such as solar panel installations.

In the coming weeks, he plans to organize a campuswide tour of rooftops for like-minded researchers interested in exploring the potential of the ground above our heads.

Bill Walter, assistant vice president for operations and services at Facilities Management & Planning, points out that the wise rooftop developer should first run his or her ideas by his department. Historical district guidelines, the safety of staff and students, and potential damage to a roof must all be considered before a project is launched.

Much rooftop development starts with the University itself. BU has contracts with cell phone companies, including AT&T, FiberTower, T-Mobile, MetroPCS, and Nextel, that give them permission to transmit signals from on high. Walter says news agencies sometimes use BU rooftops to grab video for live footage of places like Kenmore Square.

Generally, he says, the University tends to be “stingy and guarded in what we would do. We don’t advocate people going up into plain raw roof spaces.”

Despite the caution, rooftop developments have mushroomed all over (above) campus. Among them are seven solar panels and a (recently stolen) wind turbine atop the School of Education. The energy they generate, while modest, is stored in a battery or funneled back to the building’s electrical grid.

Douglas Zook, an SED associate professor and director of the science education program, says most rooftop gadgets are used more as an educational demonstration than an energy source, but that priority may change.

“We’d like to see this be the seed for sustainability,” Zook says.

Rooftops can be fertile ground for research as well. Phillips has carved out a space on top of CAS for a project that is measuring the carbon footprint of Boston. There, an antenna-like gadget captures carbon dioxide, temperature, wind, and other readings from its rooftop perch.

“It’s like a home energy audit, but we’re doing it on a much larger scale,” says Phillips, whose 30-month-long project is funded by the National Science Foundation and the U.S. Forest Service. His team is analyzing carbon exchange ranging from breath and photosynthesis to emissions and energy consumption.

Meanwhile, another team of BU researchers hopes to determine which roofing option — white, vegetated, or solar — would be the most energy-efficient choice for buildings around Boston. White roofs reflect sunlight, while black roofs absorb it. Vegetated roofs have their own solar give-and-take.

James Baldwin, a CAS visiting assistant professor of geography and environment, and a group of graduate students are using the geographic information system software ArcGIS to map building elevation and solar radiation levels across the city.

With partial funding from Phillips’ carbon emissions project, they plan to build boxlike surfaces covered in each of the three “green roof” options, and place them on the CAS roof. A device called an albedometer will measure the solar reflection of each surface, while other tools will track temperature inside the box, the energy-generating potential of each model roof, and the carbon captured by vegetated roofs. Their results could inform policy-makers and homeowners interested in cutting energy costs and maximizing the sun’s energy.

“These are simple, elegant things that can be done,” Baldwin says.

Students in the Organic Gardening Club and Compost-ability have made the CAS rooftop greenhouse a hub for sustainable activity. Started last fall by a group of graduate students studying geography and environment, Compost-ability uses the space to house three compost bins, which turn vegetable and fruit scraps into rich black soil.

“It feels good to practice what we preach and learn that there are ways to do these things in an urban environment,” says Compost-ability member Tyler Nesbit (GRS’12).

Compost-ability has one very happy rooftop neighbor. The Organic Gardening Club members will use the composted soil to grow produce year-round — tomatoes, green peppers, chives, pole beans, and squash — in pots on the greenhouse shelves.

Occasionally, says club coordinator Elizabeth Glenn (CAS’11), group members find themselves caring for houseplants that appear among the potted veggies during school breaks. Some come with signs that read, “Please water us,” says Glenn. And one forlorn mint plant used a more personal approach: “Hi, my name is Mojito. I will be staying here over break while my roommate is out of town. XOXO, Mojito.”

Leslie Friday can be reached at lfriday@bu.edu.