Potomac-Appalachian Transmission Highline
The Potomac-Appalachian Transmission Highline, or PATH, was a proposed 290-mile, 765-kilovolt transmission project connecting West Virginia with a planned substation in Maryland.
Last updated August 26, 2026
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Overview
The Potomac-Appalachian Transmission Highline (PATH) was a proposed high-voltage electric transmission project in the eastern United States. The plan called for a 290-mile, 765-kilovolt line running from the Amos Substation in Putnam County, West Virginia, to a new substation proposed near Kemptown in Frederick County, Maryland. The planned route would have crossed 13 West Virginia counties, three Virginia counties, and Frederick County, Maryland, placing the project within the territory coordinated by PJM Interconnection. PATH was developed through subsidiaries associated with Allegheny Energy and American Electric Power. Its stated planning rationale was tied to regional electricity transmission capacity and projected system overloads. The Maryland endpoint was intended to be a very large substation on agricultural land near Kemptown. Project materials described the substation as potentially the largest ever built by Allegheny Power. The proposed location was in a residential and farming area containing approximately 1,300 nearby houses and generated substantial opposition from local residents, environmental advocates, and county officials. The project encountered regulatory and land-use obstacles soon after applications were filed. In 2009, the Maryland Public Service Commission rejected the initial application as improperly filed. Regulatory officials in Virginia and West Virginia subsequently sought dismissal or rejection of related applications, in part because the Maryland termination point remained uncertain. The project also required local approval for the proposed Frederick County substation. In 2010, the Frederick County Planning Commission found the proposed facility inconsistent with the county's comprehensive plan, and the county Board of Zoning Appeals later denied the requested special exception. A request for reconsideration was also denied. PATH's planning timetable was repeatedly postponed as PJM changed the projected in-service date from 2012 to 2013, then 2014, and ultimately June 2015. Changing economic forecasts, electricity-demand assumptions, public policies, and renewable-energy planning affected the regional need analysis. In February 2011, PJM asked FirstEnergy and American Electric Power to suspend work on the project. FirstEnergy had assumed control of Allegheny Power shortly before that request. The companies withdrew their applications in Maryland, Virginia, and West Virginia. PJM formally removed PATH from its future transmission plans in August 2012, effectively ending the project in its original form. The project nevertheless continued to be referenced in later transmission-policy discussions. In May 2024, it appeared on a U.S. Department of Energy list of potential National Interest Electric Transmission Corridors. Such a designation could enable federal backstop permitting under applicable law, although the appearance on a potential-corridor list did not itself revive or approve the original project. The project also involved significant land transactions. In 2008, an associated PATH entity acquired roughly 152.2 acres at the proposed Kemptown substation site. The properties were later transferred between PATH-related entities and sold at public auction in 2017. The Kemptown site was ultimately acquired by a local nonprofit soccer organization. PATH is therefore best understood not as an operating utility brand, but as a discontinued regional infrastructure proposal whose identity was associated with transmission planning, regulatory proceedings, land-use disputes, and organized community opposition.
History
The Potomac-Appalachian Transmission Highline was conceived as a major bulk-power transmission corridor linking the Amos Substation in Putnam County, West Virginia, with a proposed substation near Kemptown in Frederick County, Maryland. The planned line would have operated at 765 kilovolts and extended approximately 290 miles through West Virginia, Virginia, and Maryland. Subsidiaries associated with Allegheny Energy and American Electric Power were identified as the prospective owners and operators. The project was presented within the context of PJM Interconnection's regional transmission planning. Its sponsors argued that additional transmission capacity was needed to address projected overloads and support the movement of wholesale electricity. The proposed Maryland endpoint would have been a large substation on agricultural land near Kemptown. The site was close to existing high-voltage infrastructure but also near a populated residential area and actively farmed properties, making the location controversial. Regulatory proceedings began in 2009. The Maryland Public Service Commission rejected the initial filing on September 9, stating that it had been improperly filed. The project did not immediately submit a replacement filing. Applications in Virginia and West Virginia also faced procedural challenges. Virginia regulators cited uncertainty over the Maryland endpoint when seeking dismissal, while a West Virginia Public Service Commission attorney moved to dismiss the state's application. The requests were described as being without prejudice, leaving open the possibility of future refiling. The Maryland substation became the central local land-use issue. In 2010, Allegheny Power applied to Frederick County for a special exception allowing the facility on agriculturally zoned land. The county Planning Commission concluded that a substation of the proposed scale and at the proposed location conflicted with the county's comprehensive plan. After hearings, the Frederick County Board of Zoning Appeals denied the special-exception application on November 18, 2010. A December request for reconsideration was also denied. The regional need for PATH became less certain as PJM repeatedly moved the projected in-service date. The target shifted from 2012 to 2013, then 2014, and later June 2015. The sponsors requested a procedural delay from West Virginia regulators in December 2010. On February 25, 2011, FirstEnergy took control of Allegheny Power. Four days later, PJM asked FirstEnergy and American Electric Power to suspend the project. PJM cited major changes in economic forecasts and evolving public policies, including policies affecting renewable energy, as reasons for renewed uncertainty in its planning studies. The sponsors withdrew PATH applications in Maryland, Virginia, and West Virginia. Community groups and environmental organizations regarded the suspension as a major victory, while project representatives emphasized that suspension did not necessarily preclude future revival. In August 2012, however, PJM's board formally removed PATH from its future plans. This decision ended the project's original development track, although its prior investments and transmission-planning assumptions continued to be discussed by interested parties. Land connected to the project also changed hands. In December 2008, PATH Allegheny Transmission Company acquired two adjoining Kemptown properties totaling about 152.2 acres. In September 2010, the land was conveyed without consideration to PATH Allegheny Maryland Transmission Company. In August 2017, the Kemptown properties and other smaller project-related properties in Maryland, Virginia, and West Virginia were offered at public auction. A Frederick, Maryland-based nonprofit soccer organization won the Kemptown properties, with settlement completed in October 2017. In May 2024, PATH appeared on a U.S. Department of Energy list of potential National Interest Electric Transmission Corridors. A corridor designation can create a federal backstop-permitting framework for qualifying transmission facilities where state approval is denied or unavailable. The listing did not constitute approval, construction authorization, or an announced restart of the original PATH project. The historical project remains generally classified as cancelled or defunct.
- 2024
Included on potential NIETC list
[1]PATH appeared on a U.S. Department of Energy list of potential National Interest Electric Transmission Corridors, without a documented restart of the original project.
- 2017
Kemptown land sold at auction
[1]The former proposed substation properties were sold at public auction and acquired by a Frederick-based nonprofit soccer organization.
- 2012
Project removed from PJM plans
[1]PJM's board formally removed PATH from future transmission plans.
- 2011
PJM requests suspension and sponsors withdraw applications
[1]PJM asked FirstEnergy and American Electric Power to suspend work. The companies subsequently withdrew PATH applications in Maryland, Virginia, and West Virginia.
- 2010
Frederick County rejects substation exception
[1]County planning and zoning authorities determined that the proposed Kemptown substation conflicted with the comprehensive plan and denied the special-exception application.
- 2009
Initial regulatory filings submitted
[1]Applications seeking approval to construct PATH were filed in the affected states. Maryland rejected its filing as improperly submitted, while Virginia and West Virginia proceedings encountered related procedural objections.
- 2008
Kemptown properties acquired
[1]An entity associated with PATH acquired approximately 152.2 acres in Kemptown, Maryland, for the planned substation site.
Products and positioning
A proposed regional grid-reliability and bulk-power transmission project, positioned by its sponsors as a means of addressing projected transmission overloads across the PJM region. Opponents characterized it as an unnecessary corridor associated with coal-fired generation and as an intrusive development near homes and agricultural land.
765-kilovolt transmission line
Potomac-Appalachian Transmission Highline
The core proposal was a roughly 290-mile, 765-kilovolt overhead transmission line from the Amos Substation in Putnam County, West Virginia, to a planned substation near Kemptown in Frederick County, Maryland. The corridor was designed as regional bulk-power infrastructure rather than a consumer-facing product. Its proposed route crossed 13 counties in West Virginia, three in Virginia, and one in Maryland, but the project was never constructed.
Electrical substation
Kemptown electrical substation
The planned Maryland endpoint was a large electrical substation in the Kemptown area of Frederick County. Project descriptions identified it as potentially the largest substation built by Allegheny Power. The site was surrounded by residential development and agricultural land, and local zoning approval was denied.
Brand decisions
2012
Remove project from regional transmission plansStrategyBackground
Following suspension and the withdrawal of state applications, PJM reassessed the project's place in its long-term transmission portfolio.
Action taken
PJM's board formally removed PATH from future plans.
Aftermath
The original project was effectively ended, although it was later mentioned in federal transmission-corridor policy discussions.
2011
Suspend and withdraw PATH applicationsStrategyBackground
The project's projected need and schedule became less certain as PJM revised the target in-service date and regional planning assumptions changed.
Action taken
PJM requested that FirstEnergy and American Electric Power suspend work, after which the companies withdrew applications in Maryland, Virginia, and West Virginia.
Aftermath
The project was removed from PJM's future plans in 2012 and was not constructed.
Recent events
- 2024
PATH appears on potential federal transmission-corridor list[1]
Regulation
The project appeared on a U.S. Department of Energy list of potential National Interest Electric Transmission Corridors, reviving policy attention without itself approving or restarting the original line.
- 2012
PJM removes PATH from future plans[1]
Other
The PJM board formally removed the transmission project from future regional plans, ending its status as an active planned project.
- 2011
PJM asks sponsors to suspend PATH work[1]
Other
PJM requested that FirstEnergy and American Electric Power suspend efforts on PATH, citing changing economic forecasts and public-policy uncertainty affecting transmission planning.
- 2010
Frederick County denies Kemptown substation zoning request[1]
Regulation
Frederick County authorities found the proposed substation inconsistent with the county's comprehensive plan and denied a special-exception request, later rejecting a request for reconsideration.
- 2009
Maryland rejects initial PATH regulatory application[1]
Regulation
The Maryland Public Service Commission rejected the project's initial application as improperly filed, adding an early regulatory obstacle to the proposed transmission line.
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