Potomac Edison, a subsidiary of FirstEnergy, is rebuilding a major 500kV transmission line in Frederick County, Md., to enhance service reliability for existing customers and accommodate future electrical load growth in Maryland and West Virginia.

The project will replace equipment that is more than 40 years old along a three-mile section of the existing transmission line, using new conductors to increase the line’s capacity by more than 60 percent. The total cost of the project is approximately $18 million, with $13 million expected to be spent in 2014.

Existing transmission structures also will be replaced with 14 new lattice steel structures from the Virginia/Maryland border to a Potomac Edison substation in Frederick County, Md. Crews are erecting the new structures within the existing right-of-way in close proximity to the structures they replace. The new structures will average 130 feet in height.

"Reconstructing this transmission line will help enhance the reliability and resiliency of the electric grid in this fast-growing region of the Mid-Atlantic," said James A. Sears, Jr., FirstEnergy’s president of Maryland operations and vice president of Potomac Edison. "This line is a vital link that’s been heavily used for years, and this rebuild project is a welcome upgrade for Potomac Edison customers and the regional transmission network."

The project was authorized by the PJM Interconnection Board in December 2010, and is scheduled for completion this summer. PJM Interconnection is the regional transmission organization that coordinates the movement of electricity and oversees reliability in all or part of 13 states and the District of Columbia.