Online NewsHour: Power outages in the west -- July 3, 1996

BLACKOUT

JULY 3, 1996

TRANSCRIPT

Margaret Warner takes a look at yesterday's blackout in parts of the American West followed by an interview by Jim Lehrer with the president of the Edison Electrical Institute.

WOMAN ON TELEPHONE: Do you know that there is an emergency at this location, because there's a lot of phones around the town that are not working?
MARGARET WARNER: This was the emergency dispatch center in Boise, Idaho yesterday. The office was flooded with calls from people who couldn't contact their friends or relatives in areas affected by the blackout. As the power outages spread across the western states yesterday afternoon, traffic lights went out, businesses went dark, and air conditioners stopped dead. In most areas, power was restored within an hour, but that was enough time for people to be stranded on rides at a county fair in San Diego.
MAN: Cars stuck up there, cars stuck up on the other end coming down the first ramp.
GIRL: All of a sudden the power went out and they had to get us off.
MS. WARNER: Utility officials are still not sure why the power outages occurred, but they suspect that when a circuit breaker failed on the giant megawatt transmission line linking Oregon and California that failure touched off a shutdown of power plants throughout the West. That domino effect was triggered because the West's power distribution system or grid is so interconnected and interdependent. Hundreds of transmission lines deliver power from nuclear, coal, and hydraulic plants to towns and cities in a 15-state area. Two power plants outside Portland, Oregon, for example, routinely send power down the coast all the way to Los Angeles. Another plant in Northern Arizona supplies power to Northern Texas. So even one plant shutdown can have an impact far beyond its immediate area.
MR. LEHRER: Now some further explanation of all this. It comes from David Swanson, vice president of Environment and Engineering at the Edison Electric Institute, the trade group for private power companies across the country. Mr. Swanson, welcome.
DAVE SWANSON, Edison Electric Institute: Thank you, Jim.
MR. LEHRER: Still no conclusive word on why this happened?
MR. SWANSON: That's right. There's no conclusive word on what the sequence of events are that triggered all of the actions that occurred, but it does appear as though the focus is on the inter-tie from the Pacific Northwest down to California.
MR. LEHRER: That's the best informed speculation. In other words, what happened? One circuit went out, one circuit breaker went out? I mean, and it just started triggering that?
MR. SWANSON: Let's switch from national elections in Russia--
MR. LEHRER: Right.
MR. SWANSON: --to a very important issue here. The inter-tie in California is comprised of several power lines that run parallel from the Pacific Northwest down to California. When all those lines are carrying the maximum amount of current, you have a very vulnerable situation in that if one of them fails, it's open. Then all the power must be carried on the other three, if there are four of them, for instance. The other three cannot carry that much power, and so you start tripping each of those lines.
MR. LEHRER: So they automatically stop, they automatically trip?
MR. SWANSON: That's right.
MR. LEHRER: Okay.
MR. SWANSON: There are safety features built into those lines to prevent them from getting overloaded. If they get overloaded, they literally melt.
MR. LEHRER: All right. So what, what the investigation is all about is what, if that theory is right, is what triggered the first line to go out?
MR. SWANSON: Yes, that's right.
MR. LEHRER: And we don't know that.
MR. SWANSON: We don't know that yet.
MR. LEHRER: What's the informed speculation? Is there any?
MR. SWANSON: Well, what you do in a situation like this, is you go back and all of these devices that are used to control the flow of power are all on timers. And so you can go back and look at which event occurred first and then you can focus on what was the engineering situation or problem that caused that event to occur. Then you can start following all of the cascading events that occur after that.
MR. LEHRER: But you've got to, first of all, start--find out where it started, right?
MR. SWANSON: That's right.
MR. LEHRER: Okay. They haven't done that yet.
MR. SWANSON: They have not done that yet.
MR. LEHRER: All right.
MR. SWANSON: It takes a while to go back and look at all those timing devices.
MR. LEHRER: Okay. Well, one of the things, of course, is that it was hot and the speculation was that it was overloaded because of, of so many air conditioners running. Does that make sense to you?
MR. SWANSON: Well, the system in the West is designed to handle very hot days like that. And there was a lot of current, about 4200 megawatts that was coming down from the Pacific Northwest.
MR. LEHRER: Now how does that--put that in some perspective--4200 megawatts.
MR. SWANSON: Well, a big thousand-megawatt nuclear power plant is a typical size for a nuclear plant. A big thousand-megawatt nuclear plant is typical for a big coal plant. That'll serve somewhere around a million and a half to two million people maybe.
MR. LEHRER: So 4500 would?
MR. SWANSON: Yes.
MR. LEHRER: Okay. All right. Go ahead. I'm sorry.
MR. SWANSON: And in the normal course of events, that's typical loading on that line.
MR. LEHRER: Mm-hmm.
MR. SWANSON: Umm, it's designed to allow for the purchase of energy from the Pacific Northwest by Californians because that's a very inexpensive source of energy, and it's got great economic assistance to the whole Southwest. There is no question that the higher loadings on those lines, the closer you come to a vulnerability.
MR. LEHRER: To the limit.
MR. SWANSON: To the limit, that's right.
MR. LEHRER: To where, if it goes beyond the limit, it automatically shuts off?
MR. SWANSON: That's right.
MR. LEHRER: And then it transfers to the other ones and shuts them off because they can't handle it, and that's what happened.
MR. SWANSON: That's the cascading event that happens, right.
MR. LEHRER: What about sabotage, is it possible? Everybody's seen all the movies where they do this all the time. Is that literally possible to--
MR. SWANSON: It's possible.
MR. LEHRER: --to stop--to start what happened yesterday through sabotage?
MR. SWANSON: Yes, yes.
MR. LEHRER: Like what? I mean, I don't mean--don't give me the diagrams, but how would you do it?
MR. SWANSON: Umm, when you know that there is a, a vulnerable situation like that, knocking out certain kinds of facilities, it certainly does have the capability of creating that kind of a cascading event. We design systems to handle many, many different kinds of, of disruptions. We have a requirement that you cannot carry energy on any series of circuits unless you can handle the most likely failure of one of them. Umm, we have to go back and look at--
MR. LEHRER: I'm not sure I follow that.
MR. SWANSON: In planning for the use of the California inter-tie, for instance--
MR. LEHRER: Mm-hmm.
MR. SWANSON: --engineers take a look at what they think the most likely failure is, and you cannot operate the system without being able to tolerate that failure and operate despite it.
MR. LEHRER: Oh, I see. To overcome it almost automatically.
MR. SWANSON: That's right.
MR. LEHRER: Okay.
MR. SWANSON: You have to have back-up capability that allows for you to operate despite that failure.
MR. LEHRER: And that includes the possibility of sabotage, in other words?
MR. SWANSON: Yes.
MR. LEHRER: Okay. All right now, this train--chain reaction.
MR. SWANSON: Mm-hmm.
MR. LEHRER: That is the way it's supposed to work, is that right?
MR. SWANSON: Yes.
MR. LEHRER: That's good news.
MR. SWANSON: The good news is that the system operated the way we designed it, the way that we wanted it to work. And what happens in a situation like this is all of a sudden because you have so much power being generated up in the Northwest, there's too much energy there to be absorbed by those users, and so you have to start shutting down power plants, and shutting down power plants, you unbalance the system and customers can be taken off of the system. They can loser their power.
MR. LEHRER: Now the worst case scenario would have been that all this energy was being generated, and these things didn't shut down, as they were supposed to.
MR. SWANSON: Yeah.
MR. LEHRER: What would have been--what would have been the consequences of that?
MR. SWANSON: You would have overloaded lots and lots of transmission lines, and they would have been damaged and the system would have collapsed because of overheated and failed transmission lines.
MR. LEHRER: And there's no evidence that that happened at all in this case?
MR. SWANSON: No. As a matter of fact, all of the safety equipment worked just the way you wanted it to.
MR. LEHRER: All right, now, what caused it to all come back on, sometimes in less than an hour, an hour and a half, three hours or whatever, is that also part of an automatic system?
MR. SWANSON: Yeah. Mm-hmm. The utility's plan for these kinds of events and what they have are various degrees of what they call load shutting down in the Southwestern part of the country, California. You had a lot more demand for energy than you had generation, and so you have to start what they call rotating blackouts in order to balance the demand with the generation capability. And so different substations were turned off, different customers got shut off. They got brought back on, others were dropped off, and you just rotate this around the system as much as you have to to balance it again.
MR. LEHRER: Now who's they? Is this seven people in a room saying, okay, let's shut down a little bit of Arizona, and let's do a little bit in Colorado, or is it all happening automatically by computer? How did all this happen yesterday?
MR. SWANSON: There are very sophisticated computers that monitor the operation of the whole western system. Each utility also has its own control area, and it has responsibilities for its customers and the generation that it controls. And so the load shutting takes place utility by utility to balance within its own service area, but under coordination through the entire western systems coordinating council.
MR. LEHRER: And that all was in effect yesterday?
MR. SWANSON: It was all in effect, and the fact that very few people were out for very long is evidence that that kind of planning is really critical to handling an event like this.
MR. LEHRER: Finally, what are the chances of this happening again?
MR. SWANSON: Very low. We--we have the best and most reliable electric system in the world. There was an event in California, December of 1994.
MR. LEHRER: I remember that.
MR. SWANSON: That is being analyzed. That has been analyzed. It's going to be compared with this one to see if there's any similarities between that event and this one, to see if it shows that some additional work needs to be done on the western system, but overall, across the country, you look at the number of, of failures that we have, and almost all of them are related to storms, they're related to the damage that's done by wind, hail, snow, and so forth, very very seldom do you find something like this, which appears to be more than an electrical problem, at a relatively small level that triggered this whole, this whole series of events.
MR. LEHRER: Okay. Dave Swanson, thank you very much.
MR. SWANSON: Thank you, Jim. A pleasure to be here.

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