Tafts Corners Substation Upgrade Project Overview:
Vermont Transco, LLC and Vermont Electric Power Company, Inc. (“VELCO”), Green Mountain Power Corporation (“Green Mountain Power”), and Vermont Electric Cooperative, Inc. (“VEC”) are collectively the “Applicants” proposing this substation upgrade Project.
The VELCO Tafts Corners substation in Williston was constructed in 2004 to support the 34.5 kV subtransmission system and designed to be expanded to serve growing distribution loads near the Williston load center. Due to projected load growth in the Williston area, as well as aged VEC distribution equipment, Green Mountain Power and VEC have a current need to increase the capacity of their distribution systems and to replace aged VEC equipment. The Town of Williston noted the need for this Project within its 2006 Town Plan.
To meet these needs, the Applicants propose to add an additional transformer and related equipment within the existing fenced-in area of the VELCO Tafts Corners transmission substation as well as related improvements to the distribution system. The Project’s distribution upgrades, to be constructed by Green Mountain Power and VEC, are not subject to approval by the Public Service Board (“Board”). Green Mountain Power will install approximately 600 feet of underground conduit along side of the current substation access road to connect its facilities to the north end of the substation, and will run underground cable from the substation to its overhead facilities along Routes 2 and 2A. VEC will place two additional distribution circuits between the south end of the substation and VEC’s existing facilities located off of Hurricane Lane (approximately 1,000 feet). VEC will use the existing electric utility right-of-way for the construction of its new distribution circuits. Much of this construction will utilize existing poles owned by the Applicants.
Applicants investigated alternatives to this substation upgrade but found them inadequate. An investigation and analysis of generation and energy efficiency measures revealed that they did not provide the same level of reliability to be considered a possible alternative. Also, VEC’s need for a replacement to its aging Williston substation would require construction of a new substation, separate from VELCO Tafts Corners, to be located in a constrained area. Green Mountain Power’s need to reduce load on its Technology Park transformer and related lines feeding Williston and surrounding area load would require expansion of one of its substations plus additional overhead distribution lines into the Williston area. The Project addresses both needs by using less new infrastructure, and installing all additional transmission equipment within the existing substation fence.
The Project and related distribution upgrades will improve the electrical system capacity and reliability for the areas of Williston, St. George, Shelburne, Technology Park in South Burlington, and South Burlington load south of Interstate 89.
Tafts Corners Phase II Project Plans:
The Project consists of installing the following equipment prior to the summer of 2009:
One new power transformer, 115/12.47 kV, rated for 25/33.3/41.7 MVA, with foundation and oil containment
Completion of the 115 kV structural steel bus with disconnect and riser structures
Three 115 kV circuit breakers
Indoor metalclad switchgear; protection, control, metering switchboards; and battery systems
As noted above, the Applicants will install this equipment within the existing fenced-in area of the VELCO Tafts Corners transmission substation at 525 Sycamore Street in Williston. The Applicants will install portions of the equipment alongside of the existing outdoor equipment and will install the remainder within the existing control building at the site. The tallest of these structures is no taller than existing equipment. Also, if the Board approves the Project as proposed, VEC intends to remove its Williston Substation near the intersection of Route 2A and Old Creamery Road.
Tafts Corners Phase II Project Impacts:
We have assessed the Project’s visual impact. Given that the Applicants will install the new substation equipment within the existing fence line, with such equipment being no taller than existing structures, the screening provided by the previously installed landscape berms and plantings shall be sufficient. Thus, the substation upgrades will not result in undue adverse aesthetics impacts. Furthermore, the Applicants have chosen to improve the existing aesthetic impacts by removing the first two 34.5 kV poles immediately south of the substation that transition up to the 34.5 kV H-frame at the edge of I-89, and replace them with a new structures built at a lower elevations within the substation.
Additionally, the Applicants have assessed the noise impacts of an additional transformer and found them to be unnoticeable, given the background noise in the immediate area.
Since the land within and immediately around the substation has been previously disturbed and does not contain any significant natural resources, the Applicants do not expect any adverse environmental impacts.
We plan to commence construction immediately after receipt of Board approval and to complete the Project before the Summer of 2009. We will be working with the affected landowners to coordinate equipment deliveries in a manner to minimize traffic impacts.
We believe this Project to be consistent with the plans of the Town of Williston and the Chittenden Regional Planning Commission as it supports existing and projected electrical loads within Williston, St. George, Shelburne and South Burlington areas, and will improve system reliablity.