Duquesne Light Company on March 15 filed with the Pennsylvania Public Utility Commission a petition requesting a waiver of the commission’s regulations governing the review and approval of the siting and construction of high-voltage electric transmission lines in relation to the company’s proposal to replace six structures on an existing line.
The structures were impacted by landslides in spring 2018, the company said, adding that replacement of the structures “is necessary in order to maintain safe and reliable service to customers because these structures are in a landslide-prone area.”
Two of the structures are original lattice steel towers with grillage foundations, while the other four were replaced with temporary emergency structures in spring 2018, each consisting of two directly embedded galvanized steel monopoles, the company said. The existing structures would be replaced with monopoles on concrete foundations that would be designed to withstand potential landslides, the company noted.
The six structures are part of the Brunot Island-Crescent double-circuit, 138-kV transmission line between the Brunot Island substation in the City of Pittsburgh and the Crescent substation in Crescent Township (BI-Crescent Line). The company added that it plans to rebuild about 14.5 miles of the BI-Crescent Line, and that that rebuild project is the subject of a separate, full application for siting and construction approval, which has been filed separate but concurrently with the filing.
However, the replacement of the six structures must occur in advance of the anticipated timeframe for approval of the full rebuild of the BI-Crescent line due to the foreseeable threat of future landslides that could damage Duquesne Light infrastructure, or cause public safety and reliability issues.
The commission’s transmission line siting and construction regulations require the filing of an application or letter of notification and obtaining commission approval before performing construction on a high-voltage transmission line or portion thereof, the company added.
The work required is expected to include the replacement of the current structures with six new weathering steel monopoles on concrete caisson foundations. Duquesne Light also said that it intends to begin construction on the six impacted structures in July and anticipates completing the work in January 2020.
While the company deems the work to be maintenance, the work arguably falls within the definition of “construction,” thereby triggering the need for commission approval for the project under 52 Pa. Code §57.71.
The work would largely occur within the existing right of way (ROW) of the transmission line, but potentially could extend beyond the ROW. If additional ROW is required to replace the six structures, the company would obtain the ROW prior to construction.
The company said that a waiver of the siting and construction approval regulations is in the public interest because there is a foreseeable potential of further landslides in the vicinity of the six structures; further landslides could further destabilize the six structures; a waiver of the siting and construction approval regulations would permit Duquesne Light to proceed with replacing the structures immediately; the work to be done would largely occur within the company’s existing ROW; and the high-voltage line in question – the BI-Crescent Line – will be the subject of a full siting and construction approval application in the near future.