The PJM Board yesterday 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 $320-370 million rebuild of the 500-kV line between the Mt. Storm substation in West Virginia and the Doubs substation in Maryland will increase the capacity of the line by more than 60 percent 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, senior vice president – 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, Maryland, 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.