July 2001

A Smarter Power Grid

Continued from page 1

By Peter Fairley

White Elephant

The U.S. power grid has been called the largest machine ever built by man. In fact it's really three loosely interconnected grids: one in Texas, and two more splitting the bulk of the country roughly along the Continental divide ( see "The Electricity Lifeline," below ). These systems are far from orderly; each grid is composed of a tangle of transmission lines operated by a hodgepodge of owners, from sprawling federal power authorities to regulated utilities to market-savvy conglomerates. An equally variable set of state, regional and federal regulators governs aspects of this mosaic, deciding how much power can enter the grids and flow over each set of lines.

The U.S. power network is built in three large grids: the Eastern, Texas and Western systems. While connected in a handful of spots by direct-current lines, the grids largely operate independently. This map shows the major lines.

Despite its structural and regulatory complexity, though, the power grid operates on a startlingly simple basis: electricity flows from where it's produced to its destination through the path of least resistance. That worked fine in the days when monolithic electrical monopolies strategically sited their power plants on the grid, with the path of least resistance leading straight to their own customers and no one else's. But those days are long gone. Deregulation of the electrical industry in the 1990s opened the grid to anyone and everyone who had electricity to sell. Dozens of brokers building new power plants and old utility giants with a fresh entrepreneurial bent now want to supply whoever offers the highest price for their power, wherever he or she may be. And that's where the physics of the existing grid comes up dangerously short.

The changing nature of the electrical industry dictates complex crisscrossing flows of electricity and the need to send more and more power over long distances. "We're trying to use [the electric grid] for a lot of longer-distance power transfers, and it's just stretching to the limit," warns Thomas Overbye, a power systems expert at the University of Illinois at Urbana-Champaign. Indeed, there already have been signs of troubles. In the blistering summer of 1996, the western U.S. electric grid snapped twice as swollen lines feeding hydroelectric power from the Pacific Northwest to California overloaded and shorted out. The result? Blackouts in 11 western states, Alberta, British Columbia, and Baja California. To avoid a repeat of that crisis, grid operators in California must restrict flows to the state, a fact that is greatly exacerbating its ongoing power crunch.

If today's situation sounds to you like a recipe for even worse power meltdowns, get your candles ready-because while hundreds of planned new power plants around the country will increase the amount of available electricity, utilities are investing next to nothing in additional transmission lines to get the juice to where it's needed. It used to be that the big utilities owned and maintained their share of the grid. But deregulation has orphaned the transmission business, uncoupling the lines that deliver electricity from revenue-producing power plants. And owning transmission lines is a business few want any part of. If you think building new power plants is unpopular, try running high-power transmission lines through someone's backyard. (Do electromagnetic radiation and contentious town-hall meetings come to mind?) Just 13,500 kilometers of high-voltage transmission additions are planned throughout North America over the next decade-a 4.2 percent increase-of which only a fraction are likely to get built. Meanwhile, the U.S. Department of Energy estimates that generating capacity in the United States alone will grow more than 20 percent over that period.

Enter power electronics-like the ones being installed at Marcy. If you can't build enough new transmission lines to keep pace with the growing power demand, it becomes imperative to build a more efficient way to direct electricity over long distances. In the same way that telecommunications companies have created a complex yet seamless network controlled by automated electronic switches that zap phone calls and data around the world, the engineering giants that build transmission systems are attempting to reenergize the grid electronically.

That transformation has already begun, as a handful of groups, like the Tennessee Valley Authority, install electronic power systems to prop up the far edges of their distribution networks, which are especially vulnerable to energy fluctuations. But even more sophisticated systems, like the one being installed at Marcy, could take electronic control to the heart of the grid. Not only could these power processors make the network more efficient, they could enable a new level of control over the transmission grid, allowing power cables to operate like toll roads and providing revenue sources that could attract the private capital badly needed to upgrade and maintain the systems.

For those wanting to make that scenario happen, the Marcy substation is a critical experiment, a high-stakes test of the technology on a system that tens of millions of people depend on for electricity. Marcy may be 300 kilometers from the bright lights of Broadway, but if power electronics can make it there, it can make it anywhere.