Environmental Assis for Orono Substation Expansion

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• Two 115 kV line terminations, each with a motor —operated transmission line switch with a quick -break line dropping whip; • One single-phase coupling capacitor voltage transformer with carrier accessories; • A 2000 amp wave trap with line tuner; and • Three 76 kV maximum continuous operating voltage station class surge arresters. Xcel Energy has or will prepare the required SWPPP and obtain a National Pollutant Discharge Elimination System (NPDES)/State Disposal System (SDS) construction stormwater permit from the Minnesota Pollution Control Agency (MPCA). Erosion control methods, described in Section 5.11 will be utilized to minimize runoff during substation construction. Upon completion of construction activities, Xcel Energy would restore the site. Post -construction reclamation activities include the removing and disposing of debris, dismantling all temporary facilities (including staging areas), employing appropriate erosion control measures, and reseeding areas disturbed by construction activities with vegetation similar to that which was removed. 4.5 Relocation of Line 0831 The Project would relocate a 1,030 -foot portion of Xcel Energy Transmission Line 0831 to HFHOA property. Clearing of trees and vegetation within the existing ROW will be conducted as needed for removing the transmission structures, conductors and related equipment. Xcel Energy will minimize access area and removal work areas to only that needed for the work. Xcel Energy has indicated that their intention is to conduct the removal work during frozen ground conditions if possible to minimize disturbance to soil. In wet areas, Xcel Energy may also install construction mats to access the removal locations (Xcel Energy, personal communication, November 11, 2011). Xcel Energy will remove above and below ground sections of the transmission structures in the planned removal area. Below ground sections of the transmission structures will be removed from the ground. Supports and guying above ground will be removed with the transmission structures and underground sections will be removed. While not expected for this Project, if concrete foundations are encountered at structures to be removed, the structure above the concrete base will be removed and then the concrete foundation removed to approximately four feet below ground surface. Holes, ruts or other areas disturbed by the removal work will be backfilled with soil and seeded to re-establish vegetation. Construction of the relocated portion of this line would follow transmission construction procedures described in Sections 4.2 and 4.3 of this document. Mitigation strategies for both line removal and construction are discussed in Section 5.0 of this document. 4.6 Great River Energy 69 kV Transmission Facilities The Project will remove 69 kV transmission facilities from the substation and the GRE 69 kV transmission line will be re-routed around the replacement substation. Xcel Energy and GRE will coordinate to modify the 115 kV remote end relay settings at Crow Rivers and Medina Substations. The 69 kV termination structure and associated foundations will be removed and a short segment of 69 kV transmission line will be constructed around the replacement substation. All work on the GRE facilities for this project will be completed on the 16 acre parcel owned by Xcel Energy. Environmental Assessment PUC Docket E002/TL-11-223 Page 18