Remember last year's big blackout? Get ready for another one
Toronto Gloge & Mail, Aug. 14, 2004 - By STEPHEN STRAUSS
A year ago today, in the middle of a steamy afternoon, 50 million people in Eastern North America were suddenly thrust back 150 years to a time when the world lived without electricity.
Because of a huge power failure affecting Ontario and several U.S. states, subways stopped running, people were trapped in elevators, automatic teller machines and air conditioning didn't function, traffic was snarled, freezers defrosted and food spoiled.
It wasn't surprising that the next day the front-page headline of a German newspaper was: Chaos in America.
While a Canadian-U.S. investigatory panel eventually determined that the cause of the blackout was an Ohio electric company's lazy tree trimming and boneheaded monitoring practices, groups of scientists and engineers have started to argue strongly that a truer reason for the largest power blackout to ever hit North America was the predictable nature of chaos itself.
And what an arcane branch of mathematics known as chaos theory suggests is anything but comforting to everyone who hopes that the 2003 power outage was an aberration that can be easily fixed.
"Blackouts are inevitable," Ian Dobson, a professor of electrical engineering at the University of Wisconsin, says simply.
Jay Apt, executive director of Carnegie Mellon's Electricity Industry Center, adds: "The prevailing paradigm is based on engineers arguing that they can engineer a system that, by God, will work. I think you can improve the system, but all the improvements in the world won't end blackouts."
The argument for the inevitability of blackouts is first based on a disturbing set of statistics. Normally, small power failures should be more common than large failures. In fact, an analysis of the small power failures that regularly occur in North America suggests that large power-grid collapses would be rare -- once every 5,000 years, suggested a recent article in the engineering journal IEEE Spectrum.
However, from 1984 to 2000, there were 11 outages greater than 4,000 megawatts, roughly the amount of energy needed to power four million average North American homes.
Thus, the big failures, even before last August's new example of chaos, were 325 times more frequent than a simple mathematical model would predict.
What's going on?
People have put forward several explanations rooted in the view that all chaotic systems -- smoke billowing from a cigarette is a classic example -- reflect an underlying sense of order.
In terms of power failures, the argument is that, although complex energy grids generally operate so as to avoid shutdowns, a variety of unavoidable negative conditions builds up in the system and one day everything that can go wrong does go wrong.
There is, however, a disagreement over the exact nature of the negative forces that trigger big blackouts.
John Doyle, a professor of control and dynamical systems at the California Institute of Technology, argues that because engineers live in a world of limited finances, they logically strive hardest to prevent small and relatively common events.
"The rare and catastrophic events are difficult to predict and hard to control, and thus are neglected," he says.
Taking a different tack, a group connected with the U.S. Department of Energy's Oak Ridge National Laboratory in Tennessee argues that a kind of historical negative-feedback loop exists in the energy industry.
Energy consumption in North America has been growing by about 2 per cent a year. To feed that growth, power companies try to maximize production. As this happens, less money is put into the prevention of catastrophic failures because the companies' attention is focused on the corporate bottom line and on meeting the demands for more electricity.
Over time, operators effectively start to cheat, temporarily overloading the grid or failing to shut off power to a small area to avoid cascading failure over a larger area. The system becomes more unstable, but, because operators keep getting away with cutting their fail-safe margins closer and closer, no fundamental changes are made.
Then a series of individually unlikely things occur on a given day and everything goes kaboom. "Something snaps and the system fails. Then you rush around and repair the network. That improves the way they operate and that increases the safety margins," Prof. Dobson says.
He adds that this creates a kind of paradox. "Everyone knows unreliability causes blackouts; it is also true that blackouts cause reliability."
But the inevitable growth of power demand leads the vicious circle to start again, he says. The system can never be perfected because it is under pressure to do two things -- produce as much power as possible now and don't have big failures later -- that are essentially incompatible, Prof. Dobson says.
This is not a mere verbal thesis. The Oak Ridge group, of which Prof, Dobson is a member, has been able to create a model that takes into account energy growth, increased power flows and random events such as lightning strikes.
These simulations eventually produce a cascading power failure. The distribution of simulated blackouts roughly reflects the pattern that has been seen in North America in recent times.
After last year's blackout, Cornell University engineering professor James Thorp used one of the equations produced by Prof. Doyle to project when the next blackout to affect tens of millions of people would occur. The last one was the infamous New York City area power outage of 1965; the mathematics predicted that the next one would be about 35 years later.
Finally, some scientists argue that even if you had all the money in the world to fix things, a power grid is too complicated to run perfectly.
Prof. Apt points out that there are 100,000 "discrete devices" -- things that can be turned on and off -- in the tangled grid of power lines and generating stations that links energy companies in Eastern Canada and the United States.
On a practical level, he and his colleagues maintain that the industry and consumers must assume that big power outages are going to happen and have contingency plans. So people should store food, batteries and water, and maybe have a backup generator or wind-up radios on hand, Prof. Apt says. While power companies should fix the immediate things that cause a blackout, he says, they should decide what things they really want to keep operating in the event of a blackout.
This might mean having agreements with some users that if the system is being overloaded, power will be cut to them to ensure that more essential services such as subways, hospitals and traffic lights can be maintained.
At least that would make the inevitability of a blackout less chaotic, Prof. Apt. says.
|
