The Virginia Department of Environmental Quality (DEQ) on June 3 submitted to state regulators recommendations regarding Axton Solar, LLC’s proposed solar generating facility in Henry and Pittsylvania counties, including that wetland and stream impacts should be avoided and minimized to the maximum extent practicable.
As noted in Axton’s April 28 application for a certificate of public convenience and necessity filed with the Virginia State Corporation Commission, the nominal 201.1-MW project consists of about 2,393 acres in western Pittsylvania County and eastern Henry County, of which about 1,759 acres would be used for the solar facility. The project would be built across about 13 noncontiguous areas, including 21 privately owned parcels in Henry County and 16 privately owned parcels in Pittsylvania County.
The solar facility would use photovoltaic (PV) electric generation system technology producing solar energy, including inverters and an on-site substation, Axton added. The project would have a rated generation capacity of 201.1 MW and would consist of about 550,611 PV modules fitted on single axis solar trackers, although exact module quantity would vary based on module type and efficiency, as determined by final design.
The PV module arrays — a row of PV modules — would be mounted on metal pipe pile or I-beam foundations 6 to 10 inches in diameter, Axton added, noting that the beams would be driven into the soil using a pile/vibratory/rotary driving technique similar to that used to install freeway guardrails. Driven pier foundations are a “concrete-free” foundation solution that would allow for easy site reclamation at the end of the project’s lifecycle, according to Axton.
PV modules would be electrically connected to adjacent modules to form module “strings” using wiring attached to the support structures, Axton said, adding that PV module strings would be electrically connected to each other through underground wiring, with wire depths being in accordance with local, state, and federal codes. String wiring terminates at PV module array combiner boxes, which are lockable electrical boxes mounted on or near an array’s support structure, Axton said, adding that output wires from combiner boxes would be routed along an underground trench system about 3.5 feet deep, including trench and disturbed area, to the inverters and transformers.
The inverters, medium-voltage transformers, and other electrical equipment are proposed to be located on manufactured platforms or skids throughout the project site, Axton said.
The project requires the use of an on-site collector substation that would be located just west of the county line in the southern portion of the project site, Axton said, noting that the substation would collect the power received from the collector lines and convert the voltage from 34.5 kV to 138 kV, as well as isolate equipment in the event of an electrical short-circuit, or for maintenance.
The project would interconnect with the American Electric Power (AEP) transmission system through a new station cut into the Axton to Danville No.l 138-kV circuit, Axton said, adding that a new three circuit breaker, 138-kV switching station — physically configured in a breaker-and-half bus arrangement, but operated as a ring-bus — would be built; installation of associated protection and control equipment, 138-kV line risers, SCADA, and 138-kV revenue metering would also be required.
Among other things, the filing noted that project construction is expected to begin in January 2023, with substantial completion by Dec. 31, 2023; testing and commissioning would occur between November 2023 and December 2023.
Noting that the business risk associated with the project, including the interconnection facilities, would be borne solely by the applicant, Axton requested waiver of the requirement to provide the project’s estimated total cost.
In its June 3 filing, the DEQ recommended that before starting project work, all surface waters on the project site should be delineated by a qualified professional and verified by the U.S. Army Corps of Engineers (the Corps) for federal jurisdictional waters and by DEQ for state jurisdictional waters.
The DEQ also recommended that no activity may substantially disrupt the movement of aquatic life indigenous to the water body, including those species that normally migrate through the area, unless the primary purpose of the activity is to impound water; culverts placed in streams must be installed to maintain low flow conditions.
Among other things, the DEQ recommended that herbicides used in or around any surface water should be approved for aquatic use by the U.S. Environmental Protection Agency or the U.S.Fish & Wildlife Service.