2.1 Overview of the Proposed Project - Keystone XL pipeline - US ...

Draft Supplemental Environmental Impact StatementKeystone XL Project2.1.12.2 Big Bend to Witten 230-kV Transmission LineAfter receipt of information on the power requirements for the proposed pump stations in SouthDakota, Western Area Power Administration (Western) conducted a joint system engineeringstudy to determine system reliability under the proposed loads at full Project electrical energyconsumption. Engineering studies determined that a 230-kV transmission line would be requiredto support voltage requirements for pump stations 20 and 21 in the Witten area when theproposed Project is operating at maximum capacity (Figure 2.1.12-2). To address thisrequirement, Western proposes to replace the existing Big Bend-Fort Thompson No. 2 230kVTransmission Line Turning Structure located on the south side of the dam, construct a newdouble circuit 230 kV transmission line for approximately 1 mile south west of the dam, andconstruct a new Lower Brule Substation. These actions are part of the larger Big Bend to Witten230 kV Transmission Line Project.Basin Electric Power Cooperative (BEPC) is proposing to construct and operate a new singlecircuit 230-kilovolt (kV) transmission line in south-central South Dakota that would extend froma new substation (Lower Brule Substation) south of the Big Bend Dam on Lake Sharpeapproximately 74 miles south-southwest to the existing Witten Substation located south of U.S.Highway 18.The approximate 76-mile Big Bend to Witten 230-kV Transmission Project(Project) consists of the aforementioned elements. The new Big Bend to Witten 230 kVtransmission line would be built, owned, and operated by BEPC. The Witten Substation wouldalso need to be expanded to accommodate the new switching equipment associated with the BigBend to Witten 230-kV transmission line (see Appendix J, Basin Electric Big Bend to Witten230-kV Transmission Project Routing Report)The Project is located within Lyman and Tripp counties in south-central South Dakota.Approximately 6 miles of the single-circuit transmission line and all of the double-circuittransmission line, as well as Western’s Lower Brule Substation, would be constructed on theLower Brule Indian Reservation (see Figure 2.1.12-2). The proposed Lower Brule Substationwould occupy approximately 16 acres of land. The existing Witten Substation would beexpanded immediately to the northeast to accommodate the new 230-kV connection. The newpart of the substation would have a separate access road and would be separated by a fence fromthe existing Witten Substation.BEPC has applied to the U.S. Department of Agriculture’s Rural Utility Service (RUS) forfinancing and proposes to construct and operate the Project to meet existing and future electricpower requirements in south central South Dakota. BEPC would interconnect the newtransmission line to the existing Western transmission system. Under RUS regulations forimplementation of NEPA, an Environmental Assessment with scoping is being prepared toassess potential impacts of the proposed action on the human and natural environment. RUS isresponsible for NEPA compliance and related statutes for the proposed Project. Since the Projectwould be constructed partly on the Lower Brule Indian Reservation, other cooperating agenciesmay be identified. RUS is the lead agency and Western is participating as the cooperatingagency. Figure 2.1.12-2 shows the proposed route and two alternative routes currently underconsideration in the Environmental Assessment process.The proposed Project would transfer power from Western’s transmission system near Big BendDam to Rosebud Electric Cooperative’s Witten Substation, near Witten, South Dakota. It isanticipated that some communication facility additions or enhancements may be necessary forProject Description 2.1-77 March 2013