The Western Area Power Administration, an agency of the U.S. Department of Energy (DOE), has written a draft Environmental Assessment (EA) on the Cliffrose Solar Interconnection Project proposed by Longview Solar LLC.
DOE on May 4 released the draft EA, with comments being taken until June 8.
Longview applied to connect the proposed Cliffrose Solar Facility to Western’s existing Griffith Substation located approximately 1.5 miles north-northeast of the proposed solar facility. Longview would make the connection via an approximately three mile, 230-kV generation intertie line (gen-tie). Longview wants to locate the proposed 45-MW photovoltaic (PV) solar facility on a site south of Kingman, Arizona, in Mohave County. The proposed solar facility site (approximately 350 acres) is located between the Hualapai Mountains (about six miles to the east) and the Black Mountains (approximately five miles to the west), in Golden Valley, Arizona, and 0.4 miles west of Interstate 40.
Western’s Proposed Action under this draft EA is to execute an interconnection agreement to connect Longview’s proposed solar facility to Western’s Griffith Substation, and to construct, own, operate, and maintain facilities supporting the physical interconnection. Western would build a new 230-kV line bay at Griffith Substation, install protection and communications equipment in the existing control house, add cables between the new bay and the control house, add metering equipment near the new bay and in the control house, and erect the gen-tie transmission line entry structure situated outside the substation fence. Western would also likely modify the Griffith Peacock and Griffith McConnico 230-kV transmission lines within existing rights-of-way to accommodate crossings by Longview’s gen-tie line. The federal action is limited to the execution of the interconnection agreement and Western’s construction, operation, and maintenance of its facilities.
The proposed solar array field would comprise approximately 200,000 PV panels on fixed-tilt mounting systems or single-axis, horizontal tracker structures supported by driven steel posts and/or other embedded foundation design. The PV modules would convert sunlight into Direct Current (DC) electricity by conveying power from each of the multiple rows of PV modules through one or more combiner boxes to an inverter. The inverter would convert the DC power to Alternating Current (AC) power, which would then either be delivered directly to an on-site switchyard or routed to a medium-voltage transformer that would step up the voltage of the power prior to delivery to the on-site switchyard. At the on-site switchyard, the power would be stepped up to 230 kV for delivery to Western’s transmission system via the gen-tie.
The proposed gen-tie would consist of an approximately three mile long single-circuit line, within an approximately 200 to 400-foot wide right of way (ROW), resulting in between 36-73 acres of disturbance. Longview would obtain, own, and maintain this ROW. The gen-tie structures would be approximately 85-foot tall steel monopoles with vertical framing. Longview would install a dual fiber optic communication path on top of the structures. The proposed gen-tie would extend north from the northwestern corner of the solar facility and terminate at a new Western 230-kV double-dead-end monopole entry structure that would direct the line into the new bay to be constructed within the Griffith Substation.