KMAX: News of the West

Nation relies on a delicate, interlocking grid system for power

By JENNIFER COLEMAN
Associated Press Writer

SACRAMENTO, Calif. (AP) It was one of the most severe U.S. power outages, an electronic tsunami that swept down the West Coast from Oregon into parts of Mexico and swiftly reached as far east as Texas.

The Aug. 10, 1996 event, like the blackout that knocked the lights out in the Northeast on Thursday, testified to just how delicate a balance is daily struck on the nation's interlocking power grids.

A series of unrelated but coincidental events had stressed out the system: Two major high-voltage lines were out for maintenance and a third shut down when it ``sagged into a tree,'' said Terry Winter, chief executive of the California Independent System Operator (ISO), the nonprofit power pool that oversees much of California's electricity grid.

It was a summer Saturday afternoon, with scorching temperatures and electricity demand unusually high, conditions more severe than Thursday's in the Northeast. The system was stressed and communications across local and state grids was less than optimum.

``What the 1996 blackouts demonstrated was these things can rapidly roll out of control and it's very important to give early warning to everyone you're interconnected with,'' said Jan Smutny-Jones, executive director of Independent Energy Producers, a Sacramento-based trade association representing power plants.

Because electricity is often transmitted over vast distances from generating plants the United States has almost a half-million miles of bulk transmission lines the national grid system depends on more than 100 control centers that serve as choke points.

The centers reroute electricity to areas of high demand, and often have automatic switches. When a grid's distribution becomes unbalanced or overloaded, a blackout occurs. When severe, it can ripple across grids, sequentially shutting them down as circuit-breakers trip so equipment isn't damaged.

That's what happened seven years ago and on Thursday, and restoring distribution isn't easy.

Post-mortems after the 1996 blackout determined that the cascade of events, affecting 4 million people in nine states, might have been lessened had regional electrical utilities communicated better, providing early notice of potential problems.

While too early to say whether Thursday's blackout may have been forestalled by improved communications, Smutny-Jones said California officials may have been able to prevent the 1996 outage had they been informed when the first transmission line went down.

The interlocking grids affected by Thursday's outage have other problems. The U.S. Department of Energy says the main regional power pools involved chiefly New York and New England have some weak transmission links that make it especially challenging to move power to urban areas during peak power periods.

The 1996 blackout came as California lawmakers were debating electricity deregulation and up to that point the state's power grid's reliability hadn't been an issue.

``That following Monday, the debate switched to reliability,'' said Smutny-Jones.

As part of the subsequent deregulation plan, the California ISO was created. The nonprofit power pool controls the ebb and flow of electricity over much of California's grid, rationing power from generating plants to meet demand.

A study by federal and state power regulators also recommended improved communications among grid managers and recommended that three reliability coordinators be named to monitor the West's grid.

Additionally, the utilities, power plants and grid operators set up plans to deal with potential blackouts that would give all parties early warning.

While Winter said the California power pool has helped power officials react quickly to outage threats, it could not prevent widespread blackouts that struck the state in 2001, when officials couldn't find enough power to import and cut electricity in rotating blocks.

State officials blamed the lack of power on energy companies that they said were withholding electricity to drive up the price. In that case, however, the blackouts were controlled by grid managers who planned how much power to cut and where to cut it.

(