Virginia State Corporation Commission (SCC) staff, in a May 30 report, said that it does not oppose Virginia Electric and Power’s d/b/a Dominion Energy Virginia’s request that the SCC issue the certificate of public convenience and necessity (CPCN) necessary for the company’s proposed Idylwood substation rebuild project.
As noted in staff’s report, the company in January filed an application with the SCC requesting approval and a CPCN to build and operate electric transmission facilities in Fairfax County, Va.
The company proposes to rebuild, relocate and replace a number of facilities and lines in and around the company’s existing Idylwood substation in Falls Church, Va., staff said, adding that no new easements would be required for the project.
As proposed, the company would shift the existing substation footprint entirely within company-owned property in order to rebuild and rearrange the substation from a straight bus arrangement to a breaker-and-a-half arrangement using Gas Insulated Substation (GIS) bus and breakers, staff said.
According to the company, staff said, the project is needed in order to comply with mandatory NERC reliability standards and PJM Interconnection reliability standards; to improve operational performance; and to maximize available land use to accommodate potential future transmission terminations and transformation at the substation.
Staff said that it verified the company’s load flow analyses based on a 2011 load forecast, as used in the application, and confirmed the existence of single and towerline contingency violations that are resolved by the proposed project. However, staff said that it agrees with testimony filed on behalf of the Fairfax County Board of Supervisors, which noted that it is reasonable and appropriate to ensure that the violations remain under updated load forecasts. As such, staff said, using the 2017 load forecast, staff also verified the continued existence of at least two thermal violations under certain contingencies.
Staff said that it “believes that the company has reasonably demonstrated a need to resolve the network reliability violations, and that the project resolves such need.”
Discussing land use maximization, staff said that the company indicates that the proposed rebuild project is needed to accommodate potential future line terminations and transformation at the substation while maximizing available land use. The company’s application identifies a future Idylwood-Scott’s Run project, which would require termination at the Idylwood substation – a project now envisioned by the company as Idylwood-Tysons, staff said, adding that to avoid confusion, that evolving planned project will be referred to in its report as “Idylwood North.”
In response to a staff interrogatory, the company states that the projected in-service date for its planned Idylwood North project is Feb. 28, 2020, although the project scope and target date may be subject to change as load projections and potential termination sites continue to be elevated, staff said. The company states that a component of the breaker-and-a-half scheme at the substation proposed as part of the rebuild is necessary for the Idylwood North project, staff said.
The company also states that portions of the proposed rebuild, including the installation of one backbone structure, would not be necessary in the absence of the planned Idylwood North project. Staff added that the company states that it does not support removing those components from the rebuild and deferring implementation of those aspects to the future Idylwood North project due to site constraints based on constructability and sequence of construction.
Staff said that while it agrees that installation of those components may become more difficult after completion of the rebuild, and that ensuring future flexibility can be prudent, the Idylwood North project has not been reviewed or approved by the SCC and could change in scope. As such, staff said, it is not clear that excluding those components from the rebuild would make more difficult a future line that may or may not be proposed, much less approved and ultimately built.
Discussing the proposed route, existing right of way (ROW) usage, and alternatives, staff noted that the project is proposed to be built entirely on property and ROW already owned and maintained by the company, which it states will reasonably minimize environmental impacts.
Of environmental, scenic and historic impacts, staff said that Dutton + Associates, LLC performed a modified pre-application analysis of the project’s impact on cultural resources, including any locations listed in or eligible for the National Register of Historic Places or the Virginia Landmarks Register and any National Historic Landmarks, within a set of tiered buffers around the project area.
Due to the presence of the substation at its existing site for many years, the presence of other transmission infrastructure in the area, and the dense suburban residential development in the project area, Dutton assigned minimal impact to the project, and did not recommend additional architectural or archaeological survey, staff said.
Staff also noted that the northern long-eared bat is potentially present in the project area, but due to existing urbanization of the area, it is not likely to be adversely affected.
Among other things, staff noted that the rebuild project, which includes a decorative brick wall and vegetation screening, uses only existing ROW and company owned property, and appears to minimize incremental impact on existing residences, scenic assets, historic districts, and the environment.
However, staff said that it recognizes that several members of the public residing adjacent to the substation have expressed safety concerns with the rebuild, and that the company is sponsoring a study to evaluate the safety of the project, which is expected to be completed in mid-June.
Staff said that it believes that the SCC may have an interest in reviewing the completed safety study to ensure that all aspects of the project can be fully evaluated. Therefore, staff said that it recommends that the company provide and address the results of that study in its rebuttal testimony, if feasible, and that the company further evaluate a “hybrid bus” option to ensure that sufficient information on that alternative is available to the SCC. That alternative would combine segments of the overhead temporary high bus with a segment of 230-kV underground cable, staff said.