PJM History
PJM Interconnection began in 1927 when three utilities, realizing the benefits and efficiencies possible by interconnecting to share their generating resources, formed the world’s first continuing power pool. It has since grown to serve over 67 million people across all or parts of 13 states and the District of Columbia.
Pennsylvania Power & Light, Philadelphia Electric Company, and Public Service Electric and Gas Company form the Pennsylvania – New Jersey Interconnection, creating an integrated power pool.
Baltimore Gas and Electric and subsidiaries of General Public Utilities join the power pool to create PJM Interconnection.
PJM installs its first online computer – an analog computer for automatic generation control.
Potomac Electric Power Company joins PJM as its sixth member.
PJM’s first digital computer is installed to run PJM’s energy management system.
PJM moves its headquarters from Philadelphia to its current location in Valley Forge, Pennsylvania.
Atlantic City Electric and Delmarva Power join PJM, bringing membership in the power pool to eight.
PJM begins the transition to an independent organization with the formation of the PJM Interconnection Association to administer the power pool.
PJM launches its first website.
PJM becomes an independent organization and opens membership to non-utilities. An independent Board of Managers is also elected.
PJM administers its first bid-based energy market.
The Federal Energy Regulatory Commission approves PJM as the nation’s first fully functioning independent system operator, or ISO.
PJM becomes the nation’s first fully functioning regional transmission organization, or RTO.
Allegheny Power and Rockland Electric join PJM.
American Electric Power, Commonwealth Edison and Dayton Power & Light join PJM.
Duquesne Light and Dominion join PJM.
The PJM Board approves its first 15-year regional electric transmission plan.
American Transmission Systems, Inc., a transmission affiliate of FirstEnergy, and Cleveland Public Power join PJM.
Duke Energy Ohio and Duke Energy Kentucky join PJM.
East Kentucky Power Cooperative joins PJM.
Ohio Valley Electric Corporation joins PJM.