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Examining The Electrical Highway Known As Grids

Aired August 15, 2003 - 14:07   ET

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.


KYRA PHILLIPS, CNN ANCHOR: Now the nuts and bolts of the power grid. CNN Technology Correspondent Daniel Sieberg has been looking at how the system is supposed to work.
(BEGIN VIDEOTAPE)

DANIEL SIEBERG, CNN TECHNOLOGY CORRESPONDENT (voice over): It's easy to take for granted, but the path of electricity from a power plant to your wall socket is rather -- well, circuitous one. Think of it like our nation's roadways. There are expressways, smaller lanes, on ramps and off ramps and intersections.

In the world of electricity, these interconnected systems are called power grids. But since electricity cannot be stored, it's generated as needed, then distributed on demand. Each state shares power with the states next door. When one runs short, a neighbor picks up the slack. That's how the power grid stays in balance, especially in the summer months when energy is in high demand.

The place where power is used, though, is often far away. Often hundreds of miles from the place where the power is generated. There are 6,000 power-generating units across the country. Here you can see the flashing red ones, where the 21 outages occurred Thursday. These units are all energized with coal, oil, gas, falling water, wind or nuclear fission.

A certain amount of power is lost as electricity travels over long transmission lines. So, there are substations along the way to boost the current to a higher voltage. The U.S. and Canada have about a half million miles of high voltage transmission lines.

The wires eventually lead to regional distribution centers which, in turn, manage the power down to local trunks and then dishes it out to local neighborhoods and homes. And there are monitors, all along the grid ready to make automatic adjustments for sudden demand or spikes in power out put.

(END VIDEOTAPE)

SIEBERG: In this case, in the Northeast, it seems as though the grid became unstable and trying to make up for a loss of electricity. There is still no word on exactly what caused the initial loss, but they will be looking closely at a troublesome part of the transmission lines, called the Lake Erie Loop, we've been hearing about.

The system shut down to isolate itself on Thursday from the failing parts of the networks. The result was a rippling effect that sequentially shut down one part of the grid after another. Once large sections are blacked out, it is difficult to restore power in a hurry. When the system is turned on again, sudden surges can create a huge strain, potentially overwhelming the system.

For that reason engineers restore power, after massive blackouts, in stages. By turning on one section of a grid after another, so as not to create any sudden demand. The kind of demand that triggered Thursday's blackout in the first place is alleviated.

Kyra.

PHILLIPS: Explain to our viewers why, for example, it didn't hit us here in Atlanta and other certain states.

SIEBERG: Right, that's a very good question because the country is actually divided up into three interconnections. There is the Western interconnection, there's the one in Texas, and there's the Eastern interconnection, that includes the South.

And basically, what happened was, in this case, the preventative measures kicked in so it didn't spread any further. But one researcher said it should have never even have spread as far as it did, so, in a sense, maybe we were lucky.

PHILLIPS: Lucky, indeed.

SIEBERG: Yes, something we all take for granted.

PHILLIPS: Thank you very much.

SIEBERG: All right.

TO ORDER A VIDEO OF THIS TRANSCRIPT, PLEASE CALL 800-CNN-NEWS OR USE OUR SECURE ONLINE ORDER FORM LOCATED AT www.fdch.com





Aired August 15, 2003 - 14:07   ET
THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.
KYRA PHILLIPS, CNN ANCHOR: Now the nuts and bolts of the power grid. CNN Technology Correspondent Daniel Sieberg has been looking at how the system is supposed to work.
(BEGIN VIDEOTAPE)

DANIEL SIEBERG, CNN TECHNOLOGY CORRESPONDENT (voice over): It's easy to take for granted, but the path of electricity from a power plant to your wall socket is rather -- well, circuitous one. Think of it like our nation's roadways. There are expressways, smaller lanes, on ramps and off ramps and intersections.

In the world of electricity, these interconnected systems are called power grids. But since electricity cannot be stored, it's generated as needed, then distributed on demand. Each state shares power with the states next door. When one runs short, a neighbor picks up the slack. That's how the power grid stays in balance, especially in the summer months when energy is in high demand.

The place where power is used, though, is often far away. Often hundreds of miles from the place where the power is generated. There are 6,000 power-generating units across the country. Here you can see the flashing red ones, where the 21 outages occurred Thursday. These units are all energized with coal, oil, gas, falling water, wind or nuclear fission.

A certain amount of power is lost as electricity travels over long transmission lines. So, there are substations along the way to boost the current to a higher voltage. The U.S. and Canada have about a half million miles of high voltage transmission lines.

The wires eventually lead to regional distribution centers which, in turn, manage the power down to local trunks and then dishes it out to local neighborhoods and homes. And there are monitors, all along the grid ready to make automatic adjustments for sudden demand or spikes in power out put.

(END VIDEOTAPE)

SIEBERG: In this case, in the Northeast, it seems as though the grid became unstable and trying to make up for a loss of electricity. There is still no word on exactly what caused the initial loss, but they will be looking closely at a troublesome part of the transmission lines, called the Lake Erie Loop, we've been hearing about.

The system shut down to isolate itself on Thursday from the failing parts of the networks. The result was a rippling effect that sequentially shut down one part of the grid after another. Once large sections are blacked out, it is difficult to restore power in a hurry. When the system is turned on again, sudden surges can create a huge strain, potentially overwhelming the system.

For that reason engineers restore power, after massive blackouts, in stages. By turning on one section of a grid after another, so as not to create any sudden demand. The kind of demand that triggered Thursday's blackout in the first place is alleviated.

Kyra.

PHILLIPS: Explain to our viewers why, for example, it didn't hit us here in Atlanta and other certain states.

SIEBERG: Right, that's a very good question because the country is actually divided up into three interconnections. There is the Western interconnection, there's the one in Texas, and there's the Eastern interconnection, that includes the South.

And basically, what happened was, in this case, the preventative measures kicked in so it didn't spread any further. But one researcher said it should have never even have spread as far as it did, so, in a sense, maybe we were lucky.

PHILLIPS: Lucky, indeed.

SIEBERG: Yes, something we all take for granted.

PHILLIPS: Thank you very much.

SIEBERG: All right.

TO ORDER A VIDEO OF THIS TRANSCRIPT, PLEASE CALL 800-CNN-NEWS OR USE OUR SECURE ONLINE ORDER FORM LOCATED AT www.fdch.com