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Winter 2012 Vol. 12 Number 2

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Transmission towers, ŠiStockphoto/Thinkstock

Inherently Vulnerable

Complexity and Diversity of the Electric Power System Could Be Easily Exploited

As much as modern life in the U.S. relies on electricity, we currently invest a "woefully inadequate" amount in upgrades and research and development to keep the system that supplies it operational, according to a report from the National Research Council. The system is incredibly complex and inherently vulnerable. While the report looked in particular at the potential for terrorist attacks to disrupt the grid -- which could be disastrous -- recent events have shown us just how vulnerable the system can be to severe weather events or simple malfunctions.

Behind the power that emerges from every wall outlet are hundreds of miles of transmission lines, substations, and large central generating stations. High-voltage transformers are a key component, increasing voltage for long distance transmission, and then reducing voltage for delivery to customers. These transformers are very expensive, difficult to move, and custom-built. Most are no longer made in the U.S., and replacing one can take months or years. The complexity and diversity of the grid system is matched by that of its owners, managers, and operators. Some parts of the system are provided by federal, state, or municipal governments; others are customer-owned cooperatives. And regulatory oversight varies by utility and location and is divided between federal, state, and local governments.

Terrorists could exploit grid vulnerability, the report says. While an attack would not immediately kill many people or make for spectacular television footage, it could deny large regions of the country access to power for weeks or months. An event of this magnitude and duration could serve terrorists' objectives by causing great hardship, widespread public anger, and an image of helplessness. In addition, such a blackout could entail costs of hundreds of billions of dollars.

The report, therefore, focuses on ways to make the power delivery system less vulnerable, strategies to restore power faster after an attack, and making sure the lights stay on for critical services like hospitals, even when delivery of conventional electric power is down. A promising solution is to develop, manufacture, and stockpile a family of universal recovery transformers that would be smaller and easier to move than the integral but cumbersome high-voltage transmitters. They would be less efficient than those normally operated and would only be for temporary use, but they could drastically reduce delays in restoring disabled electric power systems.

Although it is not reasonable to expect federal support for all local and regional planning efforts, the U.S. departments of Homeland Security and/or Energy should initiate and fund several model demonstration assessments to examine a region's vulnerability to extended power outages and develop cost-effective strategies to reduce or eventually eliminate them, the report says. Building on the results of these model assessments, DHS could then develop, test, and disseminate guidelines and tools to assist other cities, counties, states, and regions.

While the risk to the country as a whole warrants reducing vulnerability, the risk to any individual utility is small. Therefore they may need incentives such as grants or tax deductions to support incremental costs associated with building a better system. There are many technologies and strategies that could be employed to make the power system more robust in the face of terrorist attack, but research is needed to make these investments more affordable.

The report was completed in 2007, but the sponsoring agency decided at that time that the report would be classified in its entirety. After a formal request from the Research Council for an updated security classification review, the report was cleared for public release in fall 2012. A foreword to the report says that the key findings of the report remain "highly relevant." --  Lorin Hancock

Terrorism and the Electric Power Delivery System. Committee on Enhancing the Robustness and Resilience of Future Electrical Transmission and Distribution in the United States to Terrorist Attack, Board on Energy and Environmental Systems, Division on Engineering and Physical Sciences (2012, 146 pp.; ISBN 0-309-11404-7; available from National Academies Press, tel. 1-800-624-6242; $49.00 plus $5.00 shipping for single copies).

M. Granger Morgan, University Professor and head, department of engineering and public policy, Carnegie Mellon University, Pittsburgh, chaired the committee. The study was funded by the U.S. Department of Homeland Security.

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Copyright 2012 by the National Academy of Sciences