The electric power industry is in the midst of evolutionary change. The reliability events during the summer of 1999 (i.e., outages in New York City, Long Island, New Jersey, the Delmarva [Delaware-Maryland-Virginia] Peninsula, the South-Central States, and Chicago and nonoutage power disturbances in New England and the Mid-Atlantic area) demonstrate that the necessary operating practices, regulatory policies, and technological tools for dealings with the changes are not yet in place to assure an acceptable level of reliability. In a restructured environment, generation technologies and prices are a matter of private choice, yet the reliability of the delivery system benefits everyone. The operation of the electric system is more difficult to coordinate in a competitive environment, where a much larger number of parties are participating.