Virginia State Corporation Commission (SCC) staff, in a May 10 report, told the SCC that it does not oppose the issuance of a certificate of public convenience and necessity (CPCN) for Appalachian Power Company’s (APCo) modified proposed South Abingdon 138-kV Extension Transmission Line Project.
As noted in the report, American Electric Power’s (NYSE:AEP) APCo in March 2016 filed an application with the SCC for approval and issuance of a CPCN to build and operate electric transmission facilities in Washington County and the Town of Abingdon.
The project involves construction of a new 138-kV double-circuit transmission line, entirely on new right of way (ROW) and about 3.8 miles long, starting from a tap point on the company’s existing Saltville-Kingsport 138-kV transmission line; construction of a new South Abingdon substation in Washington County where the new line would end; and associated improvements at three of the company’s existing substations in the Abingdon-Washington County area.
Staff added that last October, it filed a motion for suspension of procedural schedule and a request for expedited consideration based on the representation that the company would not proceed with the project until the Federal Aviation Administration (FAA) has reviewed the final line design and made a favorable “determination of no hazard to air navigation.”
A hearing examiner granted that motion, staff said, adding that the company, the Virginia Highlands Airport Authority (VHAA), and the county on April 7 filed supplemental direct testimony; the company also filed a motion to resume procedural schedule. The company stated that the FAA in February issued its determination regarding the impact of the project’s structures on the Virginia Highlands Airport, and that the company and respondents in the case were now prepared to proceed.
The hearing examiner on April 20 granted the motion to resume and, among other things, directed staff to file its report by May 10, and set a new evidentiary hearing date of June 20.
The cost of the project, as originally proposed, is about $30m, with a desired in-service date of Dec. 1, staff added. In a subsequent filing to the SCC, the company requested a new in-service date of Dec. 31, 2018, staff said, adding that the company also presented a modification to the proposed project that would increase the project cost by about $10m, bringing to the total cost of the modified proposed project to about $40m. According to the company, the proposed project is deemed a supplemental project by PJM Interconnection, and the costs would be allocated to AEP.
The proposed modification to the project would place about 4,500 feet of the proposed transmission line underground where it crosses the eastern approaches to the airport, staff said, adding that that would eliminate all of the non-conforming and conditional structures identified by the FAA, as well as utilize the same route as the original proposed project.
According to the company, the typical ROW for that type of underground transmission line is 60 feet wide. The individual structure heights would now range from 86 feet to 131 feet, compared to 80 feet to 125 feet for the proposed project, and the average structure height above ground would also increase from 105 feet to 107 feet, staff added.
The preliminary design of the modified proposed project would utilize a total of 28 structures: 26 double circuit monopole structures with davit arms, and two 2-pole riser structures, staff said, noting that there would be a 2-pole riser structure located at each end of the underground portion of the line to transition the double circuit transmission line from underground to overhead.
According to the company, staff said, the project is needed to maintain reliability of electric distribution facilities in the southern part of the Town of Abingdon and adjacent areas of Washington County, in light of high winter peak loading in the area, as well as existing and projected load growth over a 10-year planning horizon.
In the absence of the proposed project, the company expects certain reliability issues to arise due to projected load growth. For instance:
- Abingdon substation issues include that electrical loading on the substation’s 138/12-kV Transformer No. 2 is projected to grow from 30.75 MVA, which is 100% of the transformer’s winter normal capability, to a peak winter loading of 32.1 MVA in 2017-2018. That would overload the transformer by about 4%
- Hillman Highway substation issues include that the company projects that peak winter loading on the 69/12-kV Transformer No. 1 at that substation would increase from 82% of its 30 MVA winter normal capacity, to 96% of its capacity in winter 2017/18. Winter loading would then be projected to exceed 100% of the transformer’s capacity by winter 2022-23
Staff added that it was able to verify the company’s stated needs for the proposed project. For instance, staff concurred with the company that in the absence of the proposed project, electrical loading on the Abingdon substation 138/12-kV Transformer No. 2 and Hillman Highway substation 69/12-kV Transformer No. 1 is expected to exceed the winter emergency capacity available during projected winter peak loading over a five- to 10-year planning horizon.
Staff said that it supports the modified proposed project and believes that it will improve the reliability of electric distribution facilities in the southern part of the Town of Abingdon and adjacent areas of Washington County through the load growth period forecast over the next 10 years. The preferred route appears to minimize impact on existing residences, scenic assets, historic districts, and the environment, staff said.
Staff said that in supporting the modified proposed project, it does not make its recommendation lightly, noting that its underground component represents a $10m increased cost to ratepayers. Virginia Code requires the SCC to consider, upon request, the “costs and economic benefits likely to result from requiring the underground placement of the line,” staff said.
Furthermore, staff noted that with the original proposed project no longer viable, the modified proposed project, even with its underground component, is the least costly viable option and resolves the needs identified in the application.