At 4:11 p.m. on August 14, 2003, a disturbance on the Eastern Interconnection electric grid caused massive electricity outages in the United States and Canada.
The power outage that caused the loss of service created some disturbances in the northern New Jersey and northwestern Pennsylvania sections of the PJM Interconnection grid. PJM's region includes all or parts of Delaware, Maryland, New Jersey, Ohio, Pennsylvania, Virginia, West Virginia and the District of Columbia.
At the time of the incident, PJM customers were using 61,200 megawatts of power. The disruption caused a loss of 4,500 megawatts within PJM's area -- approximately 4,100 megawatts in northern New Jersey and 400 megawatts in northwestern Pennsylvania.
As designed, PJM's systems and its operators immediately isolated the transmission system disturbance, minimizing the loss of service to customers in the PJM region. Approximately 93 percent of the PJM area remained in unaffected by the outages. Service within PJM is expected to be restored Friday morning.
As PJM completes restoration of its affected area, the organization is working with neighboring systems to aid in their restoration efforts. Principally, PJM is coordinating with the New York ISO to provide support in the restoration of the New York area.
The cause of the outage is unknown at this time, but a collaborative analysis will determine what occurred and provide recommendations for future actions.
PJM operates the world's largest competitive wholesale electricity market and North America's largest centrally dispatched control area. The company currently coordinates a pooled generating capacity of more than 76,000 megawatts and operates a wholesale electricity market with more than 200 market buyers, sellers and traders of electricity. PJM, the country's first fully functioning regional transmission organization, has administered more than $15 billion in energy and energy service trades since the regional markets opened in 1997. More than 70 nations have sent delegates to PJM to learn about its market model and the operation of the grid in a region including more than 25 million people in all or parts of Del., Md., N.J., Ohio, Pa., Va., W. Va. and the District of Columbia.