The use of emergency generators can also provide a quick and cost-effective response to restore critical loads. Many utilities have in-house emergency mobile generation or access to mobile generators through contracts with vendors. Utilities should make every effort to talk with critical customers about the importance of procuring their own backup generation to be able to respond to prolonged, unplanned outages to ensure that their critical services are available to the public in a timely manner following an attack. Utilities should also evaluate the critical loads they serve to help develop a prioritization plan for emergency generator dispatch. In addition, utilities should discuss this priority list with local governmental officials to get their input on the overall emergency response plan.

When a month-long outage hit the central business district in the city of Auckland, New Zealand, in February 1998, significant demand reduction during the restoration phase was achieved with rotating blackouts and through direct communication with customers, who were asked to remove a portion of the lamps in florescent fixtures (load reduction from 40 to 15 MW); run air conditioners on fresh air only, with reduced chiller banks and pre-cooling during off-peak hours (load reduction from 70 to 30 MW); turn off office equipment when not in use (load reduction from 25 to 20 MW); and employ various similar strategies (load reduction from 15 to 10 MW). The result was a reduction in these loads by 50 percent (Walker, 1999).

Although time-of-use meters are still rare in the United States, as they become more widespread it might be possible, with prior agreement of public utility commissions and with proper customer notification, to limit load during restoration by applying very high rates.


After any disruption that results in the physical destruction of equipment, access to replacement parts is of critical importance. Thus, for example, utilities that operate in hurricane-prone regions routinely stock large supplies of distribution poles, distribution transformers, and similar equipment and have mutual support agreements with other utilities in the event that supplies run low. Utilities also routinely provide support to each other by supplying line crews and other critical human resources in the event of such large emergencies.

The situation after a major physical terrorist attack would be similar, but the equipment needs could be quite different. Terrorists would most likely seek to destroy many large high-voltage transformers. These devices are hard to move. Most are custom designs to meet specific needs. Because such devices are very expensive, and also very reliable under normal operating conditions, most utilities have only limited numbers of spares. With few exceptions, most such transformers are no longer made in the United States, and because of large demand across the developing world, lead times at factories are very long. Thus, the greatest vulnerability in the event of terrorist physical attack on the power system will likely be securing needed replacements of high-voltage transformers.

EEI is currently spearheading the Spare Transformer Equipment Program (STEP) to catalog available spares across the industry. Over 50 utilities participated in the negotiation of a binding contract, the Spare Transformer Sharing Agreement (EEI, 2006). Any investor-owned, government-owned, or rural electric cooperative utility in the United States or Canada may participate in the program, and currently 47 utilities, representing more than 60 percent of the Federal Energy Regulatory Commission (FERC) jurisdictional transmission systems, are members. The sharing agreement provides considerable flexibility for utilities to operate and utilize assets as they normally would during the course of business, but binds utilities to share their committed transformers if an event that triggers the sharing obligations should occur. A “triggering event” is defined as an act of terrorism that destroys or disables one or more substations and results in a state of emergency as declared by the President of the United States. The Spare Transformer Sharing Agreement also provides that any participating utility may voluntarily transfer spare transformers to a participating utility or to a nonparticipating utility regardless of whether a triggering event occurs. But each participating utility that disposes of a spare transformer through “permitted transfer” is obligated to obtain a replacement transformer as soon as practical, but in no event later than 18 months after the spare transformer is disposed of. In committing spare transformers under this binding agreement, participating utilities agree to sell committed transformers to any other qualified participating utility pursuant to a properly exercised “call right” and at a set purchase price. A commitment formula utilizing “needed megavolt,” “connected megavolt,” and available spares in defined voltage classes will be utilized to determine necessary commitments for each participating utility. The needs of each participating utility will be based on the impact of losing its five most critical substations within an equipment class. The basic obligations are to:

•   Obtain qualified number of spare transformers equal to its commitment;

•   Replace spare transformers that are used in order to continue to meet its commitment;

•   Report necessary information to calculate its commitment;

•   Maintain committed spare transformers in accordance with good utility practices; and

•   Qualify for certification by an executive officer that the participating utility is complying with its commitment.

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