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Prepared Witness Testimony The House Committee on Energy and Commerce
Blackout 2003: How Did It Happen and Why?
Full Committee on Energy and Commerce
Mr. Nick Winser
Mr. Chairman, Members of the Committee. My name is Nicholas P. Winser. I am a fellow of the Institution of Electrical Engineers and have twenty years experience as an electrical engineer. I am Group Director for transmission of National Grid Transco plc, which is an international energy delivery business focusing on the transmission and distribution of electricity and natural gas in the United States and the United Kingdom. I am also Chief Executive Officer of National Grid Company, the subsidiary of National Grid Transco that owns and operates the high voltage electricity network in England and Wales. I am testifying today on behalf of National Grid USA, whose public utility subsidiaries transmit and distribute electricity in New England and New York State. National Grid USA's subsidiaries are no longer active in the electric generation business, having divested substantially all of their generating assets. In addition, National Grid USA's independent transmission company subsidiary, GridAmerica LLC, has executed contracts under which it will undertake certain responsibilities for the management and planning of the transmission assets of three major electric utilities in the Midwest, once all required regulatory approvals are obtained. Thank you for inviting me here today to address the events of August 14th and their implications for national energy policy. National Grid is pleased and honored to assist you and your Committee in the investigation of these events and in developing a comprehensive set of policies to strengthen the transmission grid. This inquiry is of particular importance to National Grid, since approximately 900,000 customers served by its New York subsidiary, Niagara Mohawk Power Corporation, lost power during the August 14th blackout. Fortunately, Niagara Mohawk personnel, working closely with the New York Independent System Operator, Inc. (NYISO), were able to restore power to all of those customers within about seven hours. While the immediate impact of the August 14th blackout on National Grid's customers was thus temporary, it was disruptive. The blackout serves as a reminder that electricity consumers are heavily dependent on the integrated interstate electricity delivery system that is straining under the weight of current demands. National Grid is committed to strengthening and expanding the transmission grid in the United States, not only by adding new transmission facilities, but also by making maximum use of existing facilities and rights-of-way. National Grid hopes that the unfortunate events of August 14th will underscore for policymakers the urgency of developing and implementing policies that will promote the establishment of a reliable and robust transmission infrastructure throughout the United States. In this statement, I will respond to the specific questions that you have asked. As you requested, I will address the important policy questions that must be considered if we are to enhance the reliability of the electric transmission grid and thereby minimize the risks of a repetition of the August 14th blackout. The Events of August 14th We do not yet have a complete picture of the underlying causes and contributing events that led to the August 14th blackout, though it appears that the initial events took place off National Grid's system. National Grid has been cooperating fully with the joint U.S.-Canadian investigation of these events, as well as other investigations, and will continue to do so. Based on preliminary review of available data, we can provide the following description of the "cascading" effects of the initial disruption on National Grid's system. So that the Committee may understand how events occurring on other utilities' systems, in this instance apparently in the Midwest, could have such profound effects on service to customers on adjoining systems, it is necessary first to explain briefly some of the principles upon which the interconnected alternating current (AC) electric transmission system operates. In order to control power flows on an AC electricity system, the frequency at all locations on the grid must be synchronized. (The interstate AC grid in the United States operates at a design frequency of sixty cycles per second.) This in turn requires that load and generation on the grid remain in close balance at all times. If there is a mismatch between load and generation on a particular portion of the grid, the frequency at that location will attempt to deviate from the desired level. Because the frequency is synchronized across the grid, energy will move across the grid in an attempt to compensate for the local imbalance. This can lead to uncontrolled power flows and severe damage to transmission and generation equipment. System operators keep some generating capacity synchronized as operating reserves in order to enable them respond to relatively small short-term fluctuations in supply and demand, including unanticipated outages of generation. To prevent damage to equipment when large imbalances between load and generation occur, automatic protective systems are in place (many of them installed after the 1965 blackout) to respond to situations in which the frequency deviates outside of a very narrow band around the acceptable system frequency. Generating equipment has protective systems that disconnect it from the transmission system if frequency deviates outside the tolerable range (whether high or low) in order to prevent damage that could otherwise render the generation unavailable to restore the system and serve load after the incident. An additional and extremely important measure put in place after the 1965 blackout as a means of restoring the balance between load and supply following a major disturbance, was the introduction of the automatic capability to reduce demand (referred to as automatic under frequency load shedding). While the use of automatic load shedding, as a last resort, plainly inconveniences the affected customers, it prevents the disturbance from spreading and causing equipment damage, which would affect more customers by delaying even further the restoration of service. The need to rely upon automatic protection systems such as programmed load shedding can be reduced by good operating practices, through which the delivery capability of the system is monitored and analyzed on an ongoing basis and actions taken in response to changes in the configuration of the system before extreme and uncontrollable conditions result. With that brief introduction in mind, I will turn to the August 14th blackout. On August 14th, the systems of National Grid and other utilities in New York State were affected by external events occurring within a very short period of time. From information made available by the North American Electric Reliability Council (NERC), it appears that a significant mismatch between load and generation developed in the Midwest (though we received no notice of the emerging conditions at the time). This caused large and abrupt swings in power flows and frequency, and protective systems tripped several transmission lines in New York State at approximately 4:10 p.m. This was the first indication we received of a disturbance. The electric system in western and central New York State separated from the system in eastern New York State. The system in western and central New York remained energized, and some load continued to be served throughout the event. In accordance with the under frequency load shedding program implemented by New York utilities in coordination with the reliability councils, automatic protective systems operated and initiated the controlled shedding of customer loads in an effort to bring the load and generation into balance. In eastern and central New York State, service was interrupted to a large number of customers, though some pockets of load were served in areas where generation was available, such as the Albany area. In most of eastern New York State, the balance between load and generation could not be maintained and the system collapsed into a blackout. As noted earlier, these events took place within a very short period of time. Indeed, many of the events occurred within a matter of seconds, well before operators could intervene manually. The transmission lines connecting the New York electric system and the New England electric system were also opened by operation of their protective systems. This separated the systems of New England and the eastern Canadian provinces from those to the west. Those systems appear to have been affected less severely by the power swings and voltage fluctuations, enabling them to remain stable, without further loss of service. In the end, New England only lost about 2,500 MW of load in Southwest Connecticut, Western Massachusetts, and Vermont for brief periods. The Operation of Protective Systems Preliminary analysis indicates that the protection schemes in place in the New York/New England region generally worked as intended to prevent more extensive and long-lasting disruptions. They allowed the system to shut down with minimal damage to key transmission and generation facilities. Most of the transmission system in New York State indeed remained intact. While keeping the key components of the transmission and generation system undamaged did not keep the lights on for all New Yorkers, doing so was crucial to facilitating the restoration of service after the event. Had critical transmission lines or generating stations suffered significant physical damage, the necessary repairs could have extended the restoration process for days or even weeks in some areas, depending upon the location and severity of the damage. On National Grid's delivery system in New York State, approximately 900,000 of the 1.5 million customers connected to National Grid's delivery facilities in upstate New York lost service on the afternoon of August 14th. Service was restored as rapidly as the available generation permitted, with all those customers back in service within approximately seven hours. The following day, as part of the restoration process, a small number of customers were again without power for a brief period, while load was being balanced with the generation that was coming back into service. The transmission control centers in New York also appeared to function well during the event. Back up power supplies to these control centers appear to have worked correctly. As a result, the control system stayed operable during the event, and the operators were able to follow established plans and communicate effectively. This also speeded the restoration process. It allowed the individual transmission owners to give instructions to the generators in their individual control areas while the NYISO coordinated bulk power restoration. The equipment and processes in place in New York State and New England therefore appear, based on preliminary analysis, to have functioned as they were designed to perform: to isolate the portion of the grid experiencing the disturbance and to protect generation and transmission facilities from serious damage when large, uncontrolled power swings occurred due to events on adjoining systems (which are still being investigated). The automatic systems that protected that equipment did so by disconnecting generation and load from the grid and by opening some transmission lines. Unfortunately, millions of customers lost power as a result. Each of the systems comprising the interconnected AC transmission system is affected by conditions on all other systems and we do not yet know exactly what happened outside of New York to cause the large, unexpected power swings that appeared on the New York State system. Accordingly, there are simply too many variables involved to tell whether the results would have been the same if the events of August 14, 2003 had transpired a year earlier. Lessons Learned and Policy Recommendations To Enhance Reliability To Guard Against the Recurrence of Similar Events Because the investigation into the events that led to the August 14th blackout is still underway, it is too early to identify the specific technical and operational solutions that are needed to minimize the likelihood that similar events might occur in the future. It is important nevertheless to recognize that continued employment of sound operating principles will reduce the risks that severe disturbances might occur on the grid in the first place. This will minimize the need to rely on automatic systems that protect equipment from damage by disconnecting components and customers from the network when such disturbances occur. Once the circumstances that gave rise to the August 14th blackout are identified, I would expect that utilities and system operators will identify any shortcomings in existing equipment and operating procedures to prevent those circumstances from repeating themselves. From a policy perspective, a significant amount of work has already been done and can still be done to address problems like those experienced on August 14th. While the investigation into the specific technical and operational issues that led to the August 14th blackout is not complete, it is critical for policymakers to take the steps necessary to promote a more reliable delivery infrastructure. Those steps cannot be limited to generation, transmission, or demand-side measures in isolation. All of these areas may well form part of an integrated solution to this complex problem. For some years, National Grid and others have raised the concern with Congress, the Federal Energy Regulatory Commission (FERC), and the Department of Energy that investment in the interconnected transmission system has not kept pace with generation and load growth and that significant upgrades are needed to maintain and enhance reliability and expand competitive markets. We have also underscored the need for active and independent management of the transmission system. As a result, we strongly advocate energy legislation and regulatory policies that address the roadblocks to grid expansion and independent transmission operation. To achieve these objectives, policymakers should focus on the following areas:
As policy objectives, these are all key steps toward a regulatory and market regime that fosters the development of a reliable delivery infrastructure. FERC's proposed Wholesale Market Platform would make significant progress in implementing the first three of these policies. It consists of a significantly revised version of the so-called standard market design that FERC proposed last year and incorporates many of the comments that FERC received on that proposal from a broad cross-section of the industry, as well as consumers and state regulators. Progress on the policies embodied in the Wholesale Market Platform proposal is essential to the development of independent transmission companies, effective regional transmission planning, and rational transmission pricing policies that would facilitate critically needed grid expansion. From what we have seen, there appears to be no substance to the speculation that electric industry restructuring and FERC's efforts to develop competitive energy markets may have contributed to the blackout. To the contrary, National Grid believes that it is those efforts that will ultimately address reliability concerns, if they are premised on independent operation of the transmission grid and focused on the development of a delivery infrastructure that is both reliable and sufficient to support competitive markets. Policymakers should also give serious consideration to the content of the reliability standards that govern the design and operation of the interconnected electric transmission system. In general, the current reliability standards call for the transmission system to be designed so that it can withstand the single largest contingency considered by planners. Many other countries (as well as portions of the U.S. grid) are designed to more stringent standards. Adopting more stringent standards generally for the U.S. transmission system would improve its capability to deal with unexpected power swings without interrupting service. National Grid believes that closely scrutinizing the content of the rules themselves and promoting transmission companies focused on planning and operating to satisfy those requirements is crucial regardless of whether compliance with the reliability standards is enforced with a new regime of mandatory rules and penalties. While the cost of improving the Nation's transmission infrastructure will have to be borne by customers in their rates, transmission represents only a small portion of the total electricity bill (ten percent or less in most cases). Since an improved transmission grid will not only enhance reliability but will improve the efficiency of energy markets and ultimately lower energy costs to consumers, even modest energy costs savings are very likely to outweigh transmission reinforcement costs. Moreover, a more reliable infrastructure will reduce the likelihood of widespread outages and the resulting costs to the economy. In short, while the specific technical and operational solutions to solve the problems of August 14th are still being identified and assessed, it is incumbent upon policymakers to continue their work to establish a regulatory environment that fosters the development of a robust transmission grid-one that will ensure reliability of the entire system and deliver efficient competitive energy markets. National Grid appreciates the opportunity to assist the Committee in its vitally important review of the causes of and solutions to the problems experienced on August 14th.
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