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26 • Physical Vulnerability of Electric Systems to Natural Disasters and Sabotage

In addition to deferring or relocating activities, households may experience out-of-pocket expenses for mitigating responses such as using block or dry ice to preserve food, firewood for heat or cooking, candles and batteries for lighting, batteries for radio/television, etc.27

Two equivalent measures of loss are the dollar amount the household would accept as compensation for the disrupted consumption pattern, and the amount the household would be willing to pay not to have its preferred consumption pattern disrupted.

Transportation

A blackout affects virtually every mode of transportation (box D). Subways, elevators, and escalators stop running, and corridor and stairwell lights usually are out. Street traffic becomes snarled without traffic lights. Gasoline pumps do not work, and the availability of taxis and buses declines over time. Parking lot gates and toll booths will not operate. Pedestrians are perhaps the least affected, although their danger increases without traffic signals and after dark with the loss of street lighting. Trains can still function, but doing so can prove hazardous without signal lights. Airports are powered by auxiliary generators that enable aircraft to land and take off in an emergency. However, considerable delays can be expected. In high-density areas where most people are dependent on public transportation, economic and other impacts are increased by the inability to get to work. Other transportation effects result from the inability to deliver goods.

Telecommunications

There is a growing reliance on telecommunications networks in all sectors of the U.S. economy. Businesses and government depend on reliable communications to perform routine tasks. Also, businesses are using their communications systems and the information stored in them to achieve a competitive advantage and to restructure their or

27 Sanghvi, op. cit., footnote 6.

ganizations on a regional or global basis. Thus, the failure of a communications system can lead not only to market losses but also to the failure of the business itself.28

The functioning of all crucial municipal public services, such as police, fire, etc., will also depend on telecommunications. A recent study by the National Research Council noted that our public communications networks are becoming increasingly vulnerable to widespread damage from natural disasters or malicious attacks.29

Extended power outages can affect telecommunications networks and lead to economic disruption. The extent of the disruption will depend on whether telecommunications networks, both public and private, have emergency backup power systems and how reliable the backup systems are. Today, many networks have their own dedicated emergency backup system. The importance of backup power systems was evidenced during Hurricane Hugo and the recent San Francisco earthquake. At the height of Hurricane Hugo, 39 central offices and 450 digital loop carrier facilities were operating on backup power. Southern Bell indicated that the facilities could operate on battery power for about 8 to 10 hours before gas or diesel generators take over.30 With the commercial power turned off in San Francisco because of the risk of fire, central offices operated on diesel generators. These diesel generators could operate for up to 7 days, according to PacBell. The earthquake did little damage to the network.31

In an emergency, commercial satellites could also be used to augment or restore a public network. Currently, only the American Telephone & Telegraph Co.'s interexchange carrier network is augmented by the Commercial Satellite Interconnectivity program, which uses surviving C-band commercial satellite resources.32

The impact of a disruption will depend on how crucial communications equipment is to a particular

28U.S. Congress, Office of Technology Assessment, Critical Connections: Communication for the Future, OTA-CIT-407 (Washington, DC: U.S. Government Printing Office, January 1990).

29 National Research Council, Growing Vulnerability of the Public Switched Networks: Implications for National Security Emergency Preparedness (Washington, DC: National Academy Press, 1989).

30Telephony, "Survival of the Network,” Oct. 23, 1989, p. 42, and "Hugo No Match for So. Bell," Sept. 25, 1989, p. 3.

31PacBell Network Survives Quake," Telephony, Oct. 23, 1989, p. 14.

32Ibid., p. 18.

Chapter 3 Impacts of Blackouts • 27

Box D-Transportation Impacts-Northeast and New York City Blackouts

The 1965 Northeast blackout occurred at 5:30 p.m.-a peak period for most modes of transportation-and lasted for up to 13 hours. The worst potential hazard was in the air, where at peak hours between 5:00 and 9:00 p.m. some 200 planes from all over the world were headed to New York's Kennedy Airport. Logan Airport in Boston, as well as numerous smaller airports, also were blacked out. Inbound flights lost visual contact as the ground lights went out. Luckily, it was a clear night, and pilots could see the other planes over the darkened cities. Planes bound for New York were diverted as close as Newark and as far as Cleveland and Bermuda. Philadelphia received 40 NY-bound airliners carrying some 4,500 passengers. Kennedy was shut down for 12 hours.1

In 1965, 630 subway trains in transit ground to a halt, trapping 800,000 passengers. Under the East River, 350 passengers had to slog to safety through mud, water, and rats. In the middle of the Williamsburg Bridge, 1,700 passengers were suspended in two trains swaying in the wind. It took police 5 hours to help everyone across a precarious 11-inch wide catwalk running 35 feet from the tracks to the bridge's roadway. A total of 2,000 trapped passengers preferred to wait it out, including 60 who spent 14 hours in a stalled train under the East River.2

Thousands of people were trapped in stalled elevators. In at least three skyscrapers, rescue workers had to break through walls to get to elevator shafts and release 75 passengers. Elevator failure resulted in the only two deaths attributable to the 1965 blackout: one person fell down a flight of stairs and hit his head, and another died of a heart attack after climbing 10 flights of stairs.3

Traffic lights failed and main arteries snarled. At unlighted intersections, countless volunteers took over the job of directing traffic. Hundreds of drivers ran out of gas as they waited for traffic to clear, only to find that service station pumps cannot work without electricity.*

In 1977, the New York airports were ordered closed at 9:57 p.m. on July 13, only minutes after the power failure. At Kennedy, 108 airline operations were scheduled between 9:00 p.m. and midnight July 13; 37 operated before the airport was closed. LaGuardia had scheduled a shutdown at midnight July 13 for runway construction, and disruption was much less significant (39 of 60 scheduled operations). Newark Airport handled 32 diverted aircraft from Kennedy and LaGuardia. Auxiliary generators supplied emergency power to the terminals, in which more than 15,000 passengers remained through the night. At Kennedy International Airport, some power returned at 3:30 a.m. on July 14, but the first authorized takeoff was not until 5:34 a.m. At both Kennedy and LaGuardia, parking lot gates and payment systems were out, and parking area employees computed fees manually. This resulted in severe traffic jams and long delays.5

The subway system fared a little better in 1977. The blackout occurred around 9:40 p.m., after most commuters were home. Also, the storm activity and brownouts offered some warning. Dispatchers running the subway system noticed power surges on the line before the blackout and radioed motormen to go to the nearest station and remain there. Thus, only seven trains in the entire system were in transit when the power went off. Emergency evacuation problems were most severe for a train stuck on the Manhattan Bridge. Even buses could not run the next day, however, because of the unavailability of fuel from electric pumps. Moreover, Grand Central Terminal was forced to close when drainage pumps lost power. Even after power was restored, flooded converters prevented electrically powered trains from using the station during the morning rush-hour on July 15, thus delaying about 75,000 daily commuters.7

The train stations in New York City halted operations during the 1977 blackout. The main inter-urban train line, AMTRAK, stopped service from the south in Newark. Going north, AMTRAK provided buses to New Haven, where trains from Boston turned around. Conrail trains serving Trenton, New Brunswick, and South Amboy experienced delays up to several hours.

After the 1977 blackout, the Metropolitan Transportation Authority initiated an $11 million program to install new equipment to ensure against massive disruption of the transit system in the event of a future blackout.9

1 "The Disaster That Wasn't," Time, Nov. 19, 1965, p. 36.

2 Ibid.

3 Ibid.

4 Ibid.

5 Systems Control, Inc., Impact Assessment of the 1977 New York City Blackout, prepared for DOE, July 1978, pp. 16, 89-90.

6 Alan McGowan, "The New York Blackout," Environment, vol. 19, No. 6, August/September 1977, p. 48.

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28 Physical Vulnerability of Electric Systems to Natural Disasters and Sabotage

industry/business. Medium- and large-size businesses that use integrated information systems to link operational processes-i.e., order entry, scheduling, etc.-will experience economic damage shortly after a power failure. While many business use a number of interconnected networks, supplied by a variety of sources (including local area networks and private and public networks), most private networks depend on public networks for transmission and switching capabilities. The Federal Government, for example, uses a number of private networks to communicate within a particular department or agency, but uses public networks to communicate outside.33

OTA has found that, in general, businesses have been slow to prepare for emergencies or adopt security measures, often postponing action until after a problem has occurred. One major reason cited is cost. Moreover, the value of communication security has to be traded off not only against cost, but also against system access and interoperability.34

Emergency Services

Emergency services include police and fire and their communications and transport, as well as hospitals. Power outages can also affect these services. All hospitals have emergency power systems to support the most critical activities, such as operating rooms, intensive-care units, emergency services, etc. Depending on the facility, auxiliary power systems may not be able to support some other activities, including x-ray, air-conditioning, refrigeration, elevators, etc. Moreover, technical problems may arise with the auxiliary generators, as evidenced in the 1977 New York blackout. In some instances, hospitals had difficulty bringing generators on-line, and were faced with generators overheating and inoperable transfer switches for connecting loads to emergency circuits.

Fire-fighting and police communications could be severely disrupted by the loss of power. Fire alarm systems may be inoperable and fire-fighting may be hampered in those areas where some power is required for pumping water.

33Ibid., pp. 82-84.

34Office of Technology Assessment, op. cit., footnote 28, ch. 10. 35 Systems Control, Inc., op. cit., footnote 18.

Moreover, the indirect impacts of a blackout, such as looting and arson, can severely strain fire-fighting and police services. For example, during the New York City blackout, 70,680 calls were made to 911, compared with the 17,700 made in a normal 24-hour period. Also, during the 1977 blackout, there were 1,037 fires (primarily arson) with over 6 large-scale fires, requiring 5 companies. More than 80 injuries were reported due to the abnormal fire activity. Exhaustion was common due to the high heat and humidity and the lack of food supplies and rest areas. 35

Public Utilities and Services

Public utilities include electric, water, gas, sewage, garbage, and related services (e.g., public health inspection).

Water supply systems generally rely on gravity to move water from reservoirs through the mains and to maintain pressure throughout the system. Some power may be required at pumping stations and reservoirs. Loss of pressure in mains hampers fire-fighting and hospitals, and may permit contaminants to seep into the water supply. Typical system pressure will supply buildings up to five or six stories tall. High-rise buildings use electric pumps to provide adequate supply on upper stories, or have roof tanks with 24- to 48-hour storage capacity. If electric pumps in high-rise buildings do not work, residents would have to go without water or get it from neighbors below.36

Electricity is needed in treatment and pumping of sewage. An outage at a treatment plant causes raw sewage to bypass the treatment process and flow into the waterways. Lack of pumping station power prevents sewage flow and ultimately causes a backup at the lowest points of input (usually basements in low-lying areas). During the 1977 New York City blackout, many of the sewage treatment plants and pumping stations in Westchester County and New York City had standby power supplies, but only for short durations. After the standby power was exhausted, untreated sewage flowed continu

1

1

36Ibid.

ously into the harbors. Signs were posted on all neighboring beaches prohibiting use.37

Costs

Outage costs attributable to essential services and infrastructure, including street and traffic lights, public transport, telecommunications, hospitals, airports, sewage and sanitation, fire and police protection, etc., are difficult to measure. For many of the essential functions, backup emergency generation already exists, although it may be unreliable or only designed to be operated for a few hours at a time. For some infrastructure services, the cost of installing standby generation should provide a reasonable order-of-magnitude estimate of outage costs. However, the costs of public transportation and lighting outages are more difficult to estimate. 38

In a blackout, electric utilities have revenue losses from unserved energy, expenses for equipment and

Chapter 3-Impacts of Blackouts • 29

overtime personnel to restore power, plus any capital investments needed to ensure that particular type of blackout does not occur again.39

Consolidated Edison suffered more than bad press in 1977. In addition to operating revenue losses from 84,000 MWh of unserved energy, and the cost of restoring power, Con Ed had to make capital and other investments (e.g., operator training programs) to upgrade system reliability.40 Moreover, Con Ed stock experienced increased trading on July 14, and closed at its lowest value for some time. The stock had a closing loss of 1.25 at the end of a week that had begun with increasing values.41

Following the 1965 blackout, utilities across the country changed their operating procedures and made capital investments in relays and circuit breakers to ensure that no single failure would again result in a cascading outage. (See ch. 4.)

37Ibid.

38 Sanghvi, op. cit., footnote 6.

39""The Diaster That Wasn't," op. cit., footnote 17.

40 Miles et al., op. cit., footnote 1.

41 Systems Control, Inc., op. cit., footnote 18.

Chapter 4

System Impact of the Loss of Major Components

A sophisticated saboteur or major natural disaster can readily cause widespread power outages. The time and effort needed for a system to recover could range from seconds to months, depending on which components are damaged, the system's basic characteristics, and the availability of spare parts. Even if a power failure is avoided or lasts only seconds, costs may be high as less efficient reserve generating capacity replaces low cost units, and sensitive consumer equipment such as computers are disabled. This chapter addresses the resilience of current bulk power systems to equipment outages, examining both reliability and economic impacts.

U.S. utilities have been highly successful in maintaining very high levels of bulk power system1 reliability. Bulk power systems in the United States are designed and operated to be reliable and economical in the face of normal events including occasional equipment failure. Utilities are also prepared to minimize the impact of some highly unlikely events such as multiple simultaneous equipment failures at a single site. However, sabotage or major natural disaster can inflict damage well beyond what utilities plan for. Because U.S. utilities have performed so reliably and have only rarely faced widespread and multiple equipment failures, there is uncertainty about how bulk systems will actually behave in extreme circumstances.

One factor leading to reliability and resilience is the highly interconnected network common to modern power systems (see box E). Because of the vast size of most power systems, no individual powerplant or transmission component is critical to the operation of any power system. An electric system typically has many powerplants, in some cases several dozen. An individual powerplant, even a large multi-unit one, supplies only a small fraction of the total demand of most control areas. There are some very small control areas in the Midwest, but

each powerplant provides only a small fraction of the total capacity in the interconnection.

Distribution systems are not designed to have such a high level of reliability as the bulk system. In fact, the great majority of outages that customers experience result from distribution system problems, not from the bulk system (around 80 percent by one estimate).2 However, unlike bulk system failures, distribution-caused outages are localized, and utilities have considerable experience in responding to them.

SHORT-TERM BULK POWER

SYSTEM IMPACTS

The Importance of Any One Component:
Preparing for Normal Failure3

Some of the thousands of components in any system occasionally fail or operate improperly, or are disabled by natural events such as lightning strikes. Because these events are common and inevitable, utilities consider them to be normal. Most bulk power systems in the United States are designed and operated to continue operation following the failure of any one device without interrupting customer service or overloading other equipment.4 This is commonly referred to as the "n-1 operating criterion." Some utilities prepare for two such contingencies (called the n-2 operating criterion). Systems west of the Rockies make some exceptions to the n-1 criterion for certain major facilities. In those systems, some customers may be briefly interrupted following certain outages, but with no overloading of other equipment leading to uncontrolled or cascading outages.

Preparing for equipment failure involves two main functions. These are: 1) holding sufficient generation and transmission capacity in reserve to

Bulk power systems include the generation and transmission, but not distribution (see U.S. Congress, Office of Technology Assessment, Electric Power Wheeling and Dealing, OTA-E-410 (Washington, DC: U.S. Government Printing Office, May 1989), ch 4). This chapter focuses on bulk systems since damage to them may be far more widespread and difficult to repair than distribution damage.

2U.S. Department of Energy, "The National Electric Reliability Study: Executive Summary," DOE/EP-0003, April 1981, as cited in: Power System Reliability Evaluation, Institute of Electrical and Electronics Engineers, 1982, p. 42.

3See Office of Technology Assessment, op. cit., footnote 1.

4North American Electric Reliability Council, Overview of Planning and Reliability Criteria of the Regional Reliability Councils of NERC (Princeton, NJ: April 1988).

"See Office of Technology Assessment, op. cit., footnote 1.

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