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Clean and green
Energy conference stresses efficiency and networking
By Tim Stoddard
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Offshore wind turbines, such as these in Denmark (above), may soon be built in Nantucket Sound. The controversial Cape Wind Project was the focus of a debate on March 10 that kicked off Building Energy 2004, a conference on energy-efficient design. |
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Motorists in some parts of the United States may confront a grim reality at the pump this summer: gasoline prices breaking the $3 barrier. Massachusetts gas prices will probably exceed $2 a gallon as the summer driving season drives up demand for gas, and Robert Kaufmann says the higher prices are not likely to come down soon. “Due to a combination of cold weather this winter and changes in the way oil companies stock oil,” he says, “the United States is now holding very low levels of crude oil stocks. This is really tending to push up prices, and it's not something that's going to change anytime soon.”
Kaufmann, a CAS professor of geography and director of graduate studies at the Center for Energy and Environmental Studies (CEES), was one of the featured speakers at Building Energy 2004, a four-day conference hosted by Boston University from March 10 to March 13. Sponsored by the Massachusetts Technology Collaborative's Renewable Energy Trust, the conference brought together architects, engineers, retailers, and other industry experts to discuss the latest in energy-efficient building practices and renewable energy sources, such as photovoltaics (which convert sunlight into electricity), wind turbines, and fuel cells.
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Robert Kaufmann, a CAS professor of geography and director of graduate studies at the Center for Energy and Environmental Studies. Photo by Jennifer Ahlen |
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Kaufmann, whose research focuses on world oil markets, explains that gas prices are soaring for two reasons. The first is that OPEC (Organization of Petroleum Exporting Countries), the world's largest oil cartel, recently announced plans to decrease its quota on April 1 to 23.5 million barrels per day, which means OPEC countries will supply less oil to the market, forcing prices up. The second reason, he adds, is that the United States has very little in the way of crude oil reserves. “Oil companies store oil just in case there's a disruption,” he says. “When their reserves run down, it makes them more vulnerable to any kind of supply disruption, and that tends to drive prices up.”
Are these higher oil prices only a temporary blip? “It depends on what you mean by temporary,” Kaufmann says. “Have we run out of easy-to-find oil, and will oil prices be high forever more? No. But as long as OPEC countries are able to cooperate, they can make higher oil prices stick for a considerable period.”
Six degrees of sustainability
Conferences are usually good venues for professional networking with colleagues and clients, and attendees at Building Energy 2004 also had an opportunity to learn about the role of real-world networks in sustainable development. Sidney Redner, a CAS professor of physics and acting chair of the department, led a session entitled Learning to Connect: A New Science of Networks, which focused on the mathematical principles underlying the networks many of us take for granted. “There are all kinds of networks around us,” he says. “Transportation networks, the World Wide Web, friendship networks. They evolve dynamically because of various sorts of constraints, resources, or personal preferences.”
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Sidney Redner, a CAS professor of physics and acting chair of the department. Photo by Kalman Zabarsky |
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Probably the best known example of a dynamic network is the six degrees of separation phenomenon, made famous in 1967 by the social scientist Stanley Milgram, who showed how Americans could be linked to one another through short chains of acquaintances. For urban planners interested in sustainable development, six degrees of separation may shed light on other complex networks, such as power grids and other utility infrastructures. How, for instance, can small, local sources of renewable energy from solar, wind, and hydroelectric generators be distributed efficiently?
As a statistical physicist, Redner has explored a different kind of network: the web of citations linking scientific papers together. “As you might imagine,” he says, “most scientific papers are rarely read. In fact, the number of papers that have zero citations, depending on the data set, can be nearly as high as 50 percent. But then there are papers that are cited 10,000 times. So how do you build a theory that describes this connectivity?”
With Paul Krapivsky, a CAS lecturer in physics, Redner has studied a mathematical model describing how citation networks change over time, and why certain papers are cited by thousands of authors. “These are incrementally growing networks where the growth is based on popularity,” he says. “Think about how word of mouth affects box office sales at movie theaters. If you hear your friends say, ‘I just saw this movie and you've gotta go see it,' you'll probably go see it. It's the same kind of thing with citations. If you write a good paper, lots of people cite it, lots of people follow it up, and it just cascades.”
While Redner did not address sustainable energy issues in his talk, he says there are many lessons from citation networks that can be applied to real-world networks such as power grids, roadways, and utility infrastructures. “Part of the appeal of networks is that they're everywhere,” he says. “There are so many different realizations of the same phenomena. The same kinds of tools and the same kinds of mathematical background can be usefully brought to bear on a diversity of problems.”
In the question and answer session following Redner's talk, a number of people in the audience steered the discussion away from sustainability issues to larger questions about human consciousness. “The human brain can be viewed as a complex network of signals running back and forth between neurons,” Redner says. “As the network becomes larger and more complex, at what point does this set of simple signals actually become a conscious person? It's an important paradigm, not necessarily in theoretical physics, but in all of science, which is this notion of emergence. When you have a complex network that's built up from lots of simple elements, something happens that we don't understand that then gives the collective system a much richer behavior than each individual element.”
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March 2004
Boston University
Office of University Relations