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Unplugged: Power Grid Failure

A power grid failure on Thursday left much of the northeastern U.S. and parts of Canada without electricity. Experts discuss the structure and vulnerability of the U.S. electrical grid system.

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  • RAY SUAREZ:

    From the moment the blackout occurred yesterday, energy experts and officials have tried to determine what caused it and where. Whatever the cause, the massive failure has raised new questions about the vulnerability of the nation's electrical power system. The North American electrical grid is made up of three large sections. Yesterday's blackout affected a large area of the eastern region.

  • Joining us now:

    Michehl Gent joins us by phone. He is president and CEO of the North American Electric Reliability Council, or NERC, which was formed after the 1965 northeast blackout to help ensure the reliability of the electric grid. William Hogan is research director for the Harvard University Electricity Policy Group and T.C. Cheng is professor of electrical engineering at the University of Southern California.

    Michehl Gent, now that we are past 24 hours since the power went off, do you have any better idea what the cause was of the blackout?

  • MICHEHL GENT:

    We have worked studiously to collect the logs of all the affected utilities and we're putting together timelines of the event. And although we have not yet found the exact cause, we have been able to find a series of events that ended up causing the blackout. We don't know what started the chain of events, but we do… we can account for how it happened.

  • RAY SUAREZ:

    A series of events. Does that explain in part the geographical finger pointing that was going on across the international border between Canada and the United States and state borders?

  • MICHEHL GENT:

    That could. And that was an incomplete list that might have caused that to happen. There is no evidence at all to suggest that Canada was involved in this. I think that, like everybody else around the Great Lakes, they were just part of the cascading outages. Our first event, our logs tell us the first event occurred somewhere with the loss of a transmission line in the Ohio area.

  • RAY SUAREZ:

    So when you say first event, once that transmission line went down, what did it cause to happen? When that first domino tumbled, what did it make or possibly make happen that eventually resulted in this wider outage?

  • MICHEHL GENT:

    We can only speculate at this time. It's probably not very smart to do that. There was an hour between the first event and then the cascading outage that lasted about nine or ten seconds. We don't yet know what caused the first event or what happened probably more importantly between the first event and the start of the cascading outage.

  • RAY SUAREZ:

    Professor Cheng, experts during the day have been reminding us that this is a system that is designed to isolate events. What could have happened yesterday that would have made the event not isolated, but in fact something that kept pushing over more and more parts of the grid until you had such a widespread outage?

  • T.C. CHENG:

    Well, of course we don't know at this point exactly what happened — as the previous gentleman just said. In general, my investigation of blackouts, which I have done for about three different blackouts on the West Coast: Two in California, one in Honolulu, Hawaii.

    Generally, there are three characteristics, three ingredients which are necessary for blackouts to occur. The first one is that usually it happens in high peak demand type of period such as in this case, where the temperatures were extremely high. As it happened also in California in 1996, rather, the high demand basically makes it very marginal that the reserves could handle any type of disturbance on a system. So that's necessary condition number one.

    Then number two has to be a triggering factor, which I call namely something unexpected happened on the system which started the cascading process. In this case, it could be the transmission failure in the Ohio situation. In our case in California, it was a transmission line failure between the Oregon and Washington border that precipitated the cascading event.

    The number three ingredient has to be that the safeguards, namely all these relays that monitor the viability of a system, have to tell the skater system which is basically a computer-based system, that something is wrong on the system. For whatever reason, that did not happen, therefore the isolation did not take place. Had isolation taken place promptly, then the area where the initial fault actually occurred could have been isolate understand and therefore the rest of the system could be spared.

  • RAY SUAREZ:

    When something like the loss of a transmission line occurs, up until then, electricity is moving through the system, people are sitting under electric lights or cooling off under an air conditioner. What starts to happen in the area where the line goes down that then pushes its effects to other places in the grid?

  • T.C. CHENG:

    Well, what happens in that particular instance is normally you have contingency plans. In other words, it's very rare that you would be supplying electricity from point A to point B with just one transmission line. So contingency plans call for that you must have, under the law, at least one, two, or three lines, that will take over downed the line, and we all know that the lines have to be maintained. They have to be down for a variety of reasons. So contingency plans normally call for much more than just one or two lines, so, in essence, if you are operating a system with sufficiently high margin of reserve, that should not be a problem. Under conditions of peak loading or very high temperatures, that could be a problem because the degree of safety, the degree of reserve is dramatically reduced.

  • RAY SUAREZ:

    Professor Hogan, taking into account what you've been hearing today about supply and demand, the way the grid is hooked up, what's the state of the landscape in a place where demand is very high and concentrated like the northeast United States?

  • WILLIAM HOGAN:

    Well, the system in the northeast United States actually works with these problems every day, and normally the system is able to handle this. So I don't think it's fundamentally a problem of supply and demand. It has to do with the unusual combination of events, the series of events that Michehl Gent was talking about. I think it will be very important to understand that. But I don't think it is just simply a single thing like stress on the system. It's stressed a lot in various times, and we can operate that system in a way that maintains reliability.

  • RAY SUAREZ:

    Is there enough transmission supply online in this quadrant of the continent? Is it merely a question of getting what is produced from place to place, rather than just a raw supply and demand question?

  • WILLIAM HOGAN:

    Well, I don't think it's a question so much as is there enough transmission. I think there is a different problem… I don't know if it was the cause here, but there is a different problem, and that is that as we learn from this experience, it's clear that this is a highly interdependent system. So what happened in Ohio has a big impact on what happens in New York City, and vice versa. And therefore, you can't solve this problem locally in the Midwest. You need a much broader perspective. That makes it a federal problem. And the Federal Energy Regulatory Commission is the place that we look to, to set up the rules for the road. How are we going to use the existing grid that we have? And we have a serious problem here in that the rules at the moment are not consistent in the different parts of the country. And the federal regulators have been trying to address this problem, but it is their proposals, which I think are actually quite good, that produced a fire storm of political objection in various places and they're stalled at the moment.

  • RAY SUAREZ:

    When you say the rules are not consistent across the zone, are there different kinds of utility companies, is that the problem, some for profit, some publicly owned, some monopolies? What do you mean by not consistent?

  • WILLIAM HOGAN:

    It's more that we are in a transition here; we're restructuring the electricity system. And we're going from a highly vertically integrated, regulated system that we used to have to a more market-like system. And that requires a different set of rules in order to operate reliably and efficiently. And we've changed the rules in some parts of the country but not in other parts. And so that's the difficulty is the inconsistency of those rules. And I think that's a problem that needs serious attention. Again, I don't know that it caused this problem. We don't know what the problem was here, but we do know that it's critical to have consistent rules. And that's a high priority and short-term task that we should addressing, and we should be supporting the Federal Energy Regulatory Commission in what it is trying to do.

  • RAY SUAREZ:

    Michehl Gent, all of our guests, starting yesterday when the power first went out, people were talking about the tremendous interdependence and intimate link-up of this grid, but isn't it that interdependence and intimate link-up that is supposed to stop things from happening as happened yesterday afternoon?

  • MICHEHL GENT:

    Yes, both of the professors spoke to this. Our organization is responsible for creating the operational rules, not the commercial or business rules, but the operational rules, and making them uniform so that events like this are not allowed to occur. Theoretically, we are supposed to have studied all of these contingencies and anticipated these things and been able to hold the outage to some local area and the entire grid would then survive. We are going to be examining this quite closely because this is the type of thing that just shouldn't happen.

  • RAY SUAREZ:

    Well, your organization was formed in the wake of the '65 blackout.

  • MICHEHL GENT:

    Yes.

  • RAY SUAREZ:

    Just for that purpose correct?

  • MICHEHL GENT:

    Exactly, yes, sir.

  • RAY SUAREZ:

    Well, what has been changed since then to make it less likely even if that didn't work yesterday?

  • MICHEHL GENT:

    We have, as Professor Hogan spoke, we have rules, we have business and we have reliability and operational rules and right now the rulings we operate by are all voluntary. We think it is essential that they become mandatory. When we examine this, the cause for this is attributable to two possibilities: one would be that we have not studied this particular system state, and that we haven't designed the rules properly to meet this particular condition. The other possibility is that some of the operators were not playing by the rules. They were just simply not following the standards.

  • RAY SUAREZ:

    Professor Cheng, if Mr. Gent's organization is closer to pinpointing the cause, if there is a relative match-up of supply and demand even now, why is it taking so long to restore power in parts of the outage zone?

  • T.C. CHENG:

    Yes, that's a very good question. Let me just answer the prior one if I may very briefly. We have to look also at the history of the power system. Basically, the system we have, the grids we have, all three of them in the country, are getting old. And there has been very little investment in terms of upgrading the grid or constructing new transmission lines or new generating stations. We know that the national demand for power is increasing annually at approximately I believe 3 percent per year. And that demand has been continuously increasing without comparable increase in the supply side. So it does come back to supply-demand a little bit in that respect.

    So when you are running a system at such a high rate of capacity, then the margin of reserve becomes very low. So that is one of the questions we have to face; namely in the future, how do we solve this problem? Do we add more transmission systems, do we add more generation capacity – that's for the long-term — in the short-term what do we have to do? So one of the things Michael mentioned, which I think is excellent is that we have to look at the operators.

    When they operate a system, do they really peak their systems to such an extent that they are losing reliability and robustness of the system? If in certain circumstances for example under high temperature conditions, you may have to institute rolling blackouts or brownouts to make sure that in case some disturbance happens, the rest of the system can react in time. And that's what happened in California two years ago. We instituted a rolling blackout and brownout in order to save the whole system from collapsing. So that may be one of the short-term solutions.

    The long-term problem has to be solved through upgrading the system and the construction of more plants and more transmission lines. The transmission lines will be an essential ingredient in the future stability of the system.

  • RAY SUAREZ:

    Professor Hogan, why the reluctance to build more transmission capacity? If there is such wide agreement that transmission is a big part of the problem, how come it hasn't risen to meet the way demand has risen?

  • WILLIAM HOGAN:

    Will, that's a good question. And part of the problem is this transition we are going through. I'm not prepared to invest in something if you don't tell me how it's going to be used and how I'm going to be… people are going to be charged and how we are going to be compensated. And we haven't specified those rules in a consistent way. That's the first step. If you know what the market and the business rules are going to be everywhere and they're sensible, then you can worry about the incentives and the expansion. But you can't get the cart before the horse here and that's the critical problem is to get the short-term rules in place, and that's what the federal regulators need to do.

  • RAY SUAREZ:

    And quickly Michehl Gent, I've heard from parts of the northeast that there are sections, neighbors that– neighborhoods, parts of the same neighborhoods where people got their juice back this morning and others, 14 hours later still don't have any. Why is that?

  • MICHEHL GENT:

    We have a distribution system that might be configured differently. You could be on one distribution circuit and your neighbor across the street could be on another. Bringing the lights back on, so to speak, is a function of people available to throw switches and the amount of energy available, the amount of generation online. We lost well over 100 generators in this excursion. So we have to match the demand with the generation exactly and be very careful as we bring this up. It just takes time. Your neighbor being on and you not being on is probably the result of him being in a different distribution feeder than you.

  • RAY SUAREZ:

    Guests, thank you all.

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