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Healing Power

Turning electricity into a commodity, however, requires changes not only to the way power is consumed, but also to the way it’s produced and distributed. With deregulation, a growing number of small power producers have begun sending electricity into the grid, and according to predictions from the U.S. Department of Energy, that number will skyrocket in coming years (see “Changing Capacity”). Thus an increasing percentage of the total supply of electricity is expected to be provided by small, independent plants, many of them using solar cells, windmills or other unconventional means to generate power. Similarly, an increasing number of large power users-factories, office buildings and others-and even some homeowners are expected to operate their own generators and sell their excess power to their local utilities. Eventually, instead of a few large plants feeding electricity into transmission systems at a few points, power producers will be scattered around the grid, most of them small and many of them contributing power only when the price for electricity goes above a certain level or when they have excess capacity.

“Distributed generation,” as this scenario is often called, could help keep electricity cheap and plentiful-and could encourage alternative power generation technologies. But for now, at least, it’s causing some technological headaches. For one thing, each new generating unit must be tied into the grid in such a way that the 60-hertz oscillation of its electrical output is synchronized with the oscillation of the entire network, says Jeff Dagle, an electrical engineer at Pacific Northwest. “A generator in Florida is in lockstep with a generator in Illinois,” he says. But there is no standardized way to establish such connections, making it difficult and expensive for nontraditional energy suppliers to hook up to the grid, says T. J. Glauthier, a former deputy secretary at the DOE who heads the Palo Alto, CA-based Electricity Innovation Institute. This in turn discourages new generators and drives up the cost of the electricity they supply, Glauthier says.

A number of startup companies are now working on affordable, standardized devices to keep small power generators in sync with the grid, and to allow them to communicate with consumers about price, availability and demand. Once such devices become available, costs should drop, and factories with backup generators or homeowners with solar cells on the roof may be able to compete with the utilities, at least on peak-load pricing.

Unfortunately, making it easy for more power suppliers to hook up to the grid could wind up threatening its stability. Today, the network’s proper functioning is the responsibility of a number of systems operators, each in charge of a large, contiguous section. The systems operator monitors the grid and issues directions for the management of the generating plants and transmission equipment. The operator’s most important function is to match electricity consumption with production, bringing new generating capacity on line as demand increases and taking it off line as demand falls. But as more power suppliers set up shop around the grid, the system becomes far more complex, says Steve Gehl, a director of strategic technology at the Electric Power Research Institute. This makes it much harder for central operators to know how the system is behaving and to direct it effectively.

The best solution, researchers from the Electric Power Research Institute suggest, may be the creation of a “self-healing grid”-a system that constantly monitors itself to spot potential problems and then correct them before they lead to power outages or other disruptions. Here’s how it would work: An array of sensors would detect everything from the voltage and current at junctions and substations, to the temperature of the air and the transmission lines, to the wind speed (a major factor in how efficiently the air cools the lines). Satellites would collect the data and forward them to a central location, where they would feed into a computer model that simulated the grid’s behavior over the coming minutes. With high-speed computers it should be possible to see problems arise in the simulations before they happen, and prevent them.

Take the case of a hot summer day, when consumers switch on their air conditioners and send demand skyrocketing. The sensors would be able to show if the transmission lines were beginning to heat up in certain spots. Before the wires could overheat enough to sag into trees, the central computers would use large electronic switches-giant transistors, in essence-to automatically reroute power as necessary, maybe even isolating a section of the grid to prevent it from taking the rest of the network down with it (see “A Smarter Power Grid,” TR July/August 2001).

The challenges to making this scenario a reality are less technical than economic and political. Indeed, Gehl says, many of the technologies needed for such a self-healing grid already exist. But, he adds, there has not been enough attention to how the technologies would be hooked together in a system. Perhaps more important, nobody has been willing to make the investments that advanced, automated control of the electricity infrastructure will demand. The problem, Gehl says, is that “it’s just not clear that people who invest in this development would be rewarded.”

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