Data Driven

Fall 2011

data-driven_story4ENERGY SMART

From the production of power to its delivery, Whiting School professors Charles Meneveau and Ben Hobbs are crunching serious numbers to understand alternative sources of energy and the most efficient ways to keep the power flowing to our communities.

Let’s take the latter first. The current system of energy delivery is an arcane and often wasteful one. Hobbs notes that, especially among the 200 utility control areas on the East Coast that include thousands of power plants, there’s almost no storage capacity for electricity. This means producers have to constantly guess at how much electricity their customers need. What’s worse, those guesses have traditionally been made several days out, to account for the lag time it takes to get big, lumbering power plants up and running. Overproduce and energy is wasted; underproduce and the risk of brownouts and blackouts soars. “It’s the ultimate ‘just-in-time’ system,” says Hobbs, the Theodore M. and Kay Schad Professor in Environmental Management and director of the Environment, Energy, Sustainability and Health Institute.

Hobbs’ recent work has looked at creating a smarter energy grid for both producer and consumers. By analyzing usage patterns and making that data easily accessible, he’s hoping to improve communication between neighboring utilities. “Right now, they don’t communicate as well as they should. And one consequence is waste. There’s some generator that’s sitting idle that’s cheap to run while another generator that’s expensive to run is operating.

“There’s also a reliability aspect,” he adds. “There’s a Department of Energy report that lays the blame for the 2003 East Coast blackout on lack of data on how much power was flowing; a utility in Ohio wasn’t aware it was overloading a line, [it] overheated, sagged, and short-circuited, and led to a chain reaction that blacked out New York City. And then there’s coordination; the utilities in Ohio and elsewhere weren’t communicating terribly well. If they had quickly switched out certain transmission lines, they could have confined the blackout.”

Hobbs’ work is addressing these issues, right down to incorporating weather forecasting. For example, by looking at wind patterns, he says it’s possible to help utilities predict bad-air-quality days and, in turn, encourage customers to use less electricity on those days to lower ozone levels.

That forecasting may well be aided by Meneveau’s research. Meneveau, the Louis M. Sardella Professor of Mechanical Engineering and deputy director of the Johns Hopkins Institute for Data Intensive Engineering and Science, is a turbulence specialist, using sophisticated modeling to predict how air currents interact with their environment. It sounds esoteric but has numerous practical implications. He notes that a better understanding of turbulence influences car, train, and ship designs to reduce losses due to drag. “Even if you reduce the drag forces by just half a percent, that translates into billions of dollars a year to the economy.”

From an energy production viewpoint, Meneveau is researching wind farms, everything from the turbulence they create (and the localized small but definitely recognizable effect on the environment), to the best arrangement of wind turbines for maximum power generation. But from a data storage and sharing perspective, his recent work with the Turbulence Database Group may be the most interesting. It involves simulating and analyzing so-called isotropic turbulence, answering statistical questions like: Given a wind vortex at a given location, what’s the probability that another vortex will be spawned or intersected with later? Such violent but fortunately rare events are associated with how kinetic energy turns into heat generation, a phenomenon that needs to be understood to better model both turbulence and the land and sea effects of wind farms.

It is a question to which 27 terabytes of information have been devoted; that’s the total amount of data in the Turbulence Database Cluster, a public, easily accessible database of detailed wind information that has already informed several papers from researchers scattered around the world.

“It’s nice, because these are the kinds of scientists who would not have been able [because of resources or technical background] to do these simulations themselves. So they were able to access [our database] and now there’s a new kind of science because people who didn’t do very large kinds of simulations before now have this user-friendly way of accessing the data. We think new things may come out of that.”

May the wind be always at their backs.