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ABSTRACT
Ohio transmission lines blamed | ||
| Leading investigator pinpoints likely cause | ||
WASHINGTON, Aug. 16 — The failure of three
transmission lines in northern Ohio was the likely trigger of the nation’s
biggest power blackout, a leading investigator said
Saturday
SAFEGUARDS FAILED
Despite the clues pointing to Ohio, investigators cannot explain why safeguards designed to isolate such a problem had failed to prevent the power failures from hopscotching around the regional electrical grid.
“If we’ve designed a system for this not to happen, how did it happen?” Gent said during Friday’s conference call. “I can’t answer that question and I’m embarrassed that I can’t, and I’m dedicated to finding out what the answer is and taking action to make sure it doesn’t happen again.”
University of Illinois engineering Professor Thomas Overbye, who has done extensive studies on the power grid’s reliability, said Thursday that one problem could have caused the large pockets of darkness that extended as far west as Michigan.
“In the electric grid there’s a good amount of redundancy, but if you lose enough lines, problems can spread,” he said. “One of the potential risks of having an interconnected system is that power problems can spread very quickly.” In situations where utilities can foresee that demand will outstrip supply, such as happened last summer during California’s energy crisis, utilities can institute “rolling blackouts,” which means cutting off electricity to certain areas for short periods of time to lessen overall energy demand.
But a sudden failure on a day when the system already is running near its maximum capacity leaves no time to institute such mitigation measures.
TRANSMISSION CAPACITY LACKING
Another factor that could have come into play is that the way electricity is moved among utilities has changed since the energy industry was deregulated in the 1990s, said Overbye.
“Interstate shipment of electric power takes place all the time, but there is just not enough transmission capacity to meet all of the needs,” he said. That’s because “the high-voltage electric transmission system was originally designed to meet the needs of local utilities,” he added, not for shipping electric power over hundreds of miles.
The difficulty in tracking down the cause of the failure illustrates the increasing complexity of the North American electricity network, which in recent decades has seen a boom in cross-border power trading, and the interdependence of the many parts and partners multiplied by energy deregulation.
About 3,170 electric utilities are connected into the U.S. power grid, grouped into three smaller groups. Thursday’s outages occurred in the Eastern Interconnected System, which extends throughout the Northeast and into the Midwest and Canada.
When one utility has a shortage, it can buy electricity from regional transmission organizations (RTOs) or an independent power generator, which essentially produces energy on a free-lance basis.
Like a river’s tributaries, their contributions spill into immense regional power grids, where they become anonymous and untraceable. Managers at dozens of control sites monitor intricate crosscurrents of supply and demand, watching over their delicate balance.
Because of that interconnectivity, a single failure can reverberate through the system and set off a catastrophic chain reaction.
The blackout already has spawned talk of overhauling the national electrical grid which many characterized as antiquated and raised new questions about whether deregulation of the power industry might have played a part in Thursday’s disruptions.
“We’re the world’s greatest superpower, but we have a Third World electricity grid,” said former Energy Secretary Bill Richardson, now governor of New Mexico.
Bruce Wollenberg, a professor of electrical engineering at the University of Minnesota and co-author of “Power Generation, Operation, and Control,” said he has heard talk among others in the electrical engineering community that the competitive atmosphere of deregulation has led some utilities and energy companies to skimp on maintenance and purchase of new equipment.
“You do that at your own peril,” he said, adding that he had no direct knowledge that companies were cutting back in those areas.
SAFEGUARDS FAILED
Despite the clues pointing to Ohio, investigators cannot explain why safeguards designed to isolate such a problem had failed to prevent the power failures from hopscotching around the regional electrical grid.
“If we’ve designed a system for this not to happen, how did it happen?” Gent said during Friday’s conference call. “I can’t answer that question and I’m embarrassed that I can’t, and I’m dedicated to finding out what the answer is and taking action to make sure it doesn’t happen again.”
University of Illinois engineering Professor Thomas Overbye, who has done extensive studies on the power grid’s reliability, said Thursday that one problem could have caused the large pockets of darkness that extended as far west as Michigan.
“In the electric grid there’s a good amount of redundancy, but if you lose enough lines, problems can spread,” he said. “One of the potential risks of having an interconnected system is that power problems can spread very quickly.” In situations where utilities can foresee that demand will outstrip supply, such as happened last summer during California’s energy crisis, utilities can institute “rolling blackouts,” which means cutting off electricity to certain areas for short periods of time to lessen overall energy demand.
But a sudden failure on a day when the system already is running near its maximum capacity leaves no time to institute such mitigation measures.
TRANSMISSION CAPACITY LACKING
Another factor that could have come into play is that the way electricity is moved among utilities has changed since the energy industry was deregulated in the 1990s, said Overbye.
“Interstate shipment of electric power takes place all the time, but there is just not enough transmission capacity to meet all of the needs,” he said. That’s because “the high-voltage electric transmission system was originally designed to meet the needs of local utilities,” he added, not for shipping electric power over hundreds of miles.
The difficulty in tracking down the cause of the failure illustrates the increasing complexity of the North American electricity network, which in recent decades has seen a boom in cross-border power trading, and the interdependence of the many parts and partners multiplied by energy deregulation.
About 3,170 electric utilities are connected into the U.S. power grid, grouped into three smaller groups. Thursday’s outages occurred in the Eastern Interconnected System, which extends throughout the Northeast and into the Midwest and Canada.
When one utility has a shortage, it can buy electricity from regional transmission organizations (RTOs) or an independent power generator, which essentially produces energy on a free-lance basis.
Like a river’s tributaries, their contributions spill into immense regional power grids, where they become anonymous and untraceable. Managers at dozens of control sites monitor intricate crosscurrents of supply and demand, watching over their delicate balance.
Because of that interconnectivity, a single failure can reverberate through the system and set off a catastrophic chain reaction.
The blackout already has spawned talk of overhauling the national electrical grid which many characterized as antiquated and raised new questions about whether deregulation of the power industry might have played a part in Thursday’s disruptions.
“We’re the world’s greatest superpower, but we have a Third World electricity grid,” said former Energy Secretary Bill Richardson, now governor of New Mexico.
Bruce Wollenberg, a professor of electrical engineering at the University of Minnesota and co-author of “Power Generation, Operation, and Control,” said he has heard talk among others in the electrical engineering community that the competitive atmosphere of deregulation has led some utilities and energy companies to skimp on maintenance and purchase of new equipment.
“You do that at your own peril,” he said, adding that he had no direct knowledge that companies were cutting back in those areas.
