Environmental Assis for Orono Substation Expansion

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3 PROPOSED PROJECT Xcel Energy proposes to construct 0.6 -miles of 115 kV overhead transmission line. The proposed route can be divided into two segments. The first segment consists of approximately 0.4 miles of new double -circuit 115 kV transmission line. The second segment would move approximately 0.2 miles of single circuit 115 kV transmission line from its existing alignment on two residential parcels in the Huntington Farm neighborhood onto property owned by the Hunt Farm Home Owners Association and adjacent to the Burlington Northern and Santa Fe (BNSF) railroad. 3.1 Purpose and Need Xcel Energy states in its route permit application that Project is proposed to improve local and system reliability, reduce the risk of overloads, and allow for additional load growth in the future. The Project is one of several transmission upgrades planned in the west metro area in response to historical and anticipated load growth. As a result of load growth, many 69 kV facilities are being upgraded to 115 W. The current Orono Substation is a single 22 MVA bank transformer distribution substation supplied by 69 kV transmission sources. The Orono Substation is currently fed at 69 kV from two directions: Dickinson and Crow River from the west and Medina from the east. Planned upgrades anticipate conversion of the existing 69 kV line between the Medina and Plymouth Substations to 115 kV (Xcel Energy and Great River Energy, 2011). This conversion will require removal of the 115/69 kV transformer at the Medina Substation due to the substation footprint. The loss of the 115/69 kV transformer means that the eastern source feeding the Orono Substation will be lost, resulting in a radial feed (only one source) into the substation. Radial loads have lower reliability than those with two sources (Xcel Energy, personal communication, November 4, 2011). Due to the loss of the 115/69 kV connection at Medina, there is not enough capacity on the 69 kV system to support the load in the area. If the Crow River 69 kV line were to be taken out of service, either through a system fault or inadvertent breaker operation, the result would be low voltages and system overloads. Xcel Energy planning criteria require voltages on the transmission system to stay at 90 percent of nominal voltage and lines are required to be loaded to less than 100 percent of their emergency capacity after a contingency. Leaving the Orono Substation on the 69 kV system would violate both of these Xcel Energy criteria (Ibid.). 3.2 Project Location The proposed project would be located in the northeastern portion of the city of Orono in Hennepin County, Minnesota. Both the Xcel Energy Proposed Route and the Baker Park Reserve Route Alternative are located in Township 11 8N, Range 23W, Sections 29, 30, and 32. A depiction of the route is shown in Figure 1. 3.3 Route Descriptions General overview maps of the routes and detailed depictions of each route are shown in Figure 1 and in Appendix B. Descriptions of the routes analyzed in this EA are provided below. Xcel Energy Proposed Route Xcel Energy proposes to construct a new 0.4 -mile long 115 kV overhead transmission line to be located in the northeastern part of the city of Orono. As described in the route permit application Environmental Assessment PUC Docket E002/TL-11-223 Page 5