American Transmission Systems Inc. was successfully integrated into PJM Interconnection at 1 a.m. EDT, June 1, 2011.

With this transition, all FirstEnergy operating companies are now under the control of regional grid operator PJM. ATSI's facilities -- which include FirstEnergy operating companies Toledo Edison, OhioEdison, Cleveland Electric Illuminating and Pennsylvania Power -- are now interconnected into the largest competitive electricity marketplace in the world serving more than 58 million customers in 13 states and the District of Columbia.

"Aligning all of our transmission facilities into PJM will enhance the long-term planning of our electric system and leverage the operating and competitive efficiencies that reflect ATSI system's strong electric ties to PJM," said Charles E. Jones, president, FirstEnergy Utilities. "PJM has ample reserves and demonstrated success with demand response programs, which will help as we manage customers' power needs, especially during extended high summer temperatures. We applaud the efforts of our stakeholders and operational teams that worked hard to make the integration successful."