The electric power transmission and distribution systems are the wires and associated equipment that carry power from central generators to end users. Such systems provide almost all of the electricity that is essential for the operation of the economy and for human well-being. They also are difficult to protect and have been attacked by terrorists elsewhere in the world. Therefore, it is important to think about what can be done to make them less vulnerable to attack, how power can be rapidly restored if an attack occurs, and how important services can be sustained while the power is out. This report explores all of these issues, describes the current situation, and makes recommendations for improvements.

This report was requested by the U.S. Department of Homeland Security as part of its efforts to protect the nation’s critical infrastructure. The National Research Council (NRC) established the Committee on Enhancing the Robustness and Resilience of Future Electrical Transmission and Distribution in the United States to Terrorist Attack to conduct the study. The committee’s statement of task is given in Appendix A. Committee members were selected from academia, industry, state government agencies, and other organizations. They brought considerable expertise on electric power networks, their operation and regulation, security, and other issues. Biographical sketches of the committee members are presented in Appendix B.

The committee met six times in 2005 and 2006 to gather information from public sources (listed in Appendix C) and to discuss the key issues. It also held several conference calls.

Throughout the study the committee worked carefully to balance the need to explore issues with sufficient depth to ensure that key decision makers and other readers can understand the problem well enough to take informed action, while at the same time not laying out a “cookbook” that tells terrorists how to plan an attack that would do maximum damage. Thus, for example, the committee has been intentionally vague about some specific vulnerabilities or some modes of attack.

Chapter 1 frames the problem. It briefly describes the transmission and distribution systems; notes the differences between common disruptions and intentional attacks on the system; asks who might want to attack the system; and explores what the impact of such attacks might be.

Chapter 2 analyzes the structure and operation of the transmission and distribution system affecting the vulnerabilities that it faces. In the three chapters that follow the committee discusses the vulnerabilities of the system in terms of physical attack (Chapter 3); cyber security for guarding against/thwarting attacks on communications, sensors, and controls (Chapter 4); and the people who run, or have access to, the system (Chapter 5).

Chapter 6 focuses on how the system can be protected and how it can be modified to minimize the damage if it is attacked.

Once portions of the transmission and distribution system have been disrupted, restoring service becomes important. Chapter 7 discusses how this is currently done, how restoration

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