PJM Interconnection, a regional transmission organization that ensures the reliability of eastern U.S. high-voltage grids, last week approved $1.25 billion in transmission improvements, including a capacity improvement project to rebuild one of the most heavily used transmission lines in PJM.

The $320 to $370 million rebuild of the 500-kV line between the Mt. Storm substation in West Virginia and the Doubs substation in Maryland is expected to increase the capacity of the line by more than 60% by improving electrical clearance and adding conductors.

“In addition, after reviewing several options, the board reaffirmed the need to move ahead with the PATH project,” said Michael J. Kormos, the grid operator’s senior vice president of operations. “The project is the most robust solution to the reliability needs we identified.”

Originally approved in 2007, the 277-mile, 765-kV Potomac-Appalachian Transmission Highline (PATH) between West Virginia and Frederick, Md. has a required in-service date of June 1, 2015, and an estimated cost of $2.1 billion.

During 2010, the PJM board has authorized $3.92 billion in transmission additions and upgrades as part of PJM’s 15-year Regional Transmission Expansion Plan. More than $19.02 billion in transmission improvements have been authorized since PJM’s formal planning process began in 2000, the organization said.

Source: PJM