The U.S. electric power system is widely recognized as being among the mostreliable in the world. With very few exceptions, the nation’s bulk power trans-mission system-the system that carries power long distances at high voltages-has reliably delivered a continuous supply of electric power that has met consumer and business needs during the past several decades. This strong record of uninterrupted service has been made possible through the cooperative efforts of the utilities that are linked together on the three major U.S. transmission grids. Since the establishment of the North American Electric Reliability Council (NERC) in 1968 following the 1965 blackout in the northeastern states, electric utilities throughout Canada and the United States have worked together to establish and implement voluntary operating rules and procedures to keep power flowing throughout the entire region.