Regional grid operator PJM Interconnection last week told developers of the Potomac-Appalachian Transmission Highline (PATH) that the 275-mile, 765-kV project was the most “robust and effective” means to ensure long-term reliability of the Mid-Atlantic grid, and that it was imperative it be placed into service by June 1, 2015.

American Electric Power (AEP) and Allegheny Energy, joint owners of the project, said they would move forward quickly with the project.

Last December, the companies withdrew a previously submitted application to build the line in Virginia based on PJM’s determination that PATH would not be needed, as initially projected, in 2014. At a meeting last week, however, PJM’s Board of Managers reviewed the progress of the 2010 Regional Transmission Expansion Plan (RTEP), including “analysis specific to the need for the PATH project,” PJM Vice President of Planning Steven R. Herling told the energy companies in a letter (PDF).

“From this analysis it is clear that significant voltage and thermal violations of reliability criteria persist, requiring additional transmission capability to be put in place, at the latest, by June 1, 2015. At this time we have identified over thirty violations of thermal criteria and numerous violations of voltage criteria,” he wrote. Herling asked the companies to proceed with all efforts related to PATH, including state regulatory proceedings, “assuming a required in-service date for the project of June 1, 2015 at the latest.”

AEP and Allegheny said in a joint statement that the project had been evaluated against six alternatives and “found to be the most comprehensive solution to resolve numerous voltage-related issues and line overloads that are projected to begin in mid-2015.”

The new data will be incorporated into the existing applications for regulatory approval in Maryland and West Virginia, as well as in a new application to be filed in Virginia in the third quarter, they said.

The line will extend from the Amos substation in Putnam County, W.Va., to a proposed substation in Frederick County, Md. Permissions have been sought from the Maryland Public Service Commission for a 20-mile segment running through that state. The West Virginia Public Service Commission is also reviewing an application for authorization to construct the PATH project in West Virginia.

Sources: PATH, PJM