PATH - Potomac-Appalachian Transmission Highline: Overview and Schedule

Key Milestones

Q1 2008
Allegheny and AEP began working on a routing study and environmental assessment in early January.

Q1 2009
The companies plan to file applications for regulatory approvals in the affected states, following the completion of the routing study. The state regulatory approval process is expected to take about a year.

2013
Project managers will pursue a construction schedule that will require timely regulatory approvals in order to meet a targeted in-service date of 2013.

Overview and Schedule
In 2007, PJM Interconnection, Inc. approved upgrades to the region’s electric transmission system, including the construction of a new high-voltage transmission line from southwestern West Virginia to central Maryland, designed to maintain the reliability of the regional transmission system.

Allegheny Energy and American Electric Power (AEP) have announced a joint venture to build the Potomac-Appalachian Transmission Highline (PATH), a new transmission line to expand the regional electric transmission grid.

The PATH project will consist of a single 765-kilovolt (kV) transmission line from AEP’s Amos substation near St. Albans, W.Va., to a new substation near Kemptown, southeast of Frederick, Md. The project also will include a new mid-point substation in the vicinity of eastern Grant County, northern Hardy County or Hampshire County in West Virginia.

Why is PATH Needed?

Our country’s top energy experts, including the U.S. Department of Energy, the North American Electric Reliability Corporation and PJM Interconnection, have called for new transmission lines to be built to prevent looming reliability concerns. The transmission grid works like a highway system, moving electricity throughout the region. And we have a traffic jam on that system. If something is not done to relieve stress on the transmission grid in the next few years, there could be adverse effects to our region, including blackouts.
The recommendation to build PATH is driven by reliability concerns. PATH is the recommended solution to avoid overloading several existing transmission lines. It will help to maintain reliable operation of the grid during periods of high customer demand and to avoid problems that could lead to blackouts.
PATH is one of two new transmission lines that are urgently needed in the region. Even after Allegheny’s proposed 500-kV Trans-Allegheny Interstate Line (TrAIL) goes into service, the existing transmission system will continue to face the risk of line overloads. Both lines are needed to ensure long-term reliability.
Overloads threaten the electric power supply system across the region, and blackouts can result from overloads. As we all saw during the blackout of 2003, electric power supply troubles in one area can quickly spread. Because of the interconnected nature of the grid, the entire region benefits from the new facilities.