WASHINGTON (AP) _ The largest power blackout in American history prompted new calls Friday for overhauling the nation's electricity system. Investigators said the power disruptions likely began in the Midwest but they have yet to pinpoint the cause.
Investigators said they are focusing on a massive electrical grid that encircles Lake Erie, moving power from New York to the Detroit area, into Canada and back to New York state. There had been problems with the transmission loop in the past, officials said.
The head of the North American Electric Reliability Council, who earlier said northern Ohio may have been the flashpoint, later backed way from reaching any conclusion ``until we're absolutely certain.''
``We had some indication that the first transmission lines that were tripped were in the Midwest. .. We're not certain that is where it started,'' said Michehl Gent, president of NERC, an industry sponsored group that tracks power grids to assure their reliability.
At a news conference, Gent provided a picture of the enormity of the blackout that began Thursday at 4:11 p.m. and raced from New England to Michigan and southeastern Canada.
He said more than 100 power plants _ including 22 nuclear reactors in the United States and Canada _ were shut down, and the blackout affected 50 million people over a 9,300-square-mile area from New England to Michigan.
He said a preliminary determination of the cause of the cascading power disruption, which raced through the system in less than 10 seconds, may not be available until next week and more detailed investigations could last months.
``We never anticipated we would have a cascading outage'' like this, said Gent, adding that he was ``personally embarrassed'' because his organization is supposed ``to see that this doesn't happen.''
While NERC closely watches grid reliability, it has no power to force transmission companies to comply with standards or correct violations.
Some in Congress have urged creation of an agency that would have industry police power. The issue is likely to be debated next month when lawmakers consider energy legislation.
Gent said the investigation could find that someone violated industry standards or that the standards are not adequate. He ruled out completely reports of a lightning strike or a fire in a New York City facility and said weather appeared not to have been a factor in the blackout.
He said electricity capacity was adequate when the blackout hit.
The investigation is focusing on ``the Lake Erie Loop,'' a massive transmission system that goes through New York state south of the Great Lakes to Detroit and then up through Canada, down by Niagara Falls, back to New York, said Gent.
``That's the center of the focus. This has been a problem for years and there have been all sorts of plans to make it more reliable,'' he said.
At one point, 300 megawatts of power were traveling east on the loop and suddenly reversed direction, resulting in an estimated 500 megawatts suddenly moving west, he said. It was uncertain what caused the sudden shift.
The focus on Ohio earlier had been criticized by Ohio officials.
The chairman of the Ohio Public Utilities Commission, Alan Schriber, called it ``speculation at best'' and said industry experts he contacted Friday continued to focus attention on Canada and upstate New York.
And a private company that monitors the grid said its technology showed the problem started in Michigan. ``That was the epicenter,'' insisted David Trungale, vice president of SoftSwitching Technologies Inc., of Middleton, Wis.
One reason it may be so difficult to pinpoint the cause is the speed in which the cascading outages raced across the Northeast and Ohio Valley as well as southeastern Canada.
Trungale said his company's monitoring stations recorded a power disruption in Connecticut only 2 seconds after the first problem was recorded in Michigan. He declined to describe the Michigan site further.
``It all happened in about 9 seconds,'' said Gent, the NERC president.
A spokeswoman for FirstEnergy Corp., whose electricity service area stretches along Lake Erie in Ohio, declined to speculate on the cause of the disruption.
``We do not have enough information at this point,'' said Kristen Baird, a spokeswoman for FirstEnergy, based in Akron, Ohio. ``Our focus at this point is restoring service.''
William Museler, president of the New York Independent System Operator, which manages the state's electric grid, said ``huge'' power fluctuations originating from a Midwest power plant started the downfall of the grid at 4:11 p.m. Thursday. He said the power swings became so large that the Ontario system could not sustain them, and the problem migrated to New York.
As the power fluctuated, generators in New York tripped off to protect themselves, an act of self-preservation that made it possible to restore power Friday morning, Museler said.
Still, New York Gov. George Pataki said the systematic failure should never have happened and operators of the sprawling grid owe the public answers. He said the cascading problem should have been isolated by safeguards in the system. ``That just did not happen,'' he said.
Gent said he was fairly confident terrorism wasn't involved. ``There's no evidence of a blow up or somebody breaking into something,'' he said.
A member of the federal agency that regulates transmission lines said the resumption of power also was being hampered because the ``transmission system _ our (power) highway _ is so weak and so fragile.''
``It's very clear this is not about deregulation. It's about investing in the transmission system,'' said Nora Brownell, a member of the Federal Energy Regulatory Commission.
After the 1965 blackout hit the Northeast, the industry sought to put in safeguards that would isolate future transmission problems. In some cases this worked.
In Vermont, a quick shutdown of power feeds from New York helped the state avoid major outages. Likewise, the vast mid-Atlantic regional grid, known as the PJM Interconnection, was spared problems across most of its system.