4. Proposed Project4
PG&E's Tri Valley 2002 Capacity Increase Project is proposed to serve its projected electric demand in the cities of Dublin, Livermore, Pleasanton, and San Ramon, and in portions of unincorporated Alameda and Contra Costa Counties adjacent to these cities. PG&E's proposed project consists of approximately 20.7 miles of 230 kV overhead double-circuit transmission line, approximately 2.7 miles of 230 kV underground double-circuit transmission line, two new distribution substations, modifications to an existing substation, and an underground/overhead transition station. The components of PG&E's proposed project are addressed as four parts, one for each of the three major geographic areas of the project (Pleasanton, Dublin/San Ramon, and North Livermore), cumulatively referred to as Phase 1, and one for PG&E's proposed Phase 2, which is not immediately needed.
4.1 Pleasanton Area Proposed Project
In the Pleasanton area, the project consists of modification of the existing Vineyard Substation (in Pleasanton) to include a 230 kV transmission interconnection. PG&E proposes to install 2.8 miles of new 230 kV overhead double-circuit transmission line and 2.7 miles of 230 kV underground double-circuit transmission line to serve the Vineyard Substation, and a transition station to convert the 230 kV overhead transmission line to an underground cable system.
The proposed overhead transmission route would originate approximately 1.0 mile east of the entrance to the Vallecitos Nuclear Center along Route 84, originating in PG&E`s existing Tesla-Newark transmission line corridor, which is occupied by four rows of lattice steel towers. The proposed transmission line would connect with the existing Contra Costa-Newark #2 transmission line and travel north on lattice steel towers for approximately 2.8 miles through gently to moderately steep sloped rangeland toward the City of Pleasanton. The transition to underground would occur approximately halfway between the origination point and the Vineyard Substation.
The transition station5 would be constructed below the natural ridgeline where, in part due to landscape screening, visibility from the City of Pleasanton would be minimized. The layout would require an area of 0.2 to 0.5 acres, including vehicle access, and would be graded flat or in a terraced layout. An access road to the transition station would be built from the City of Pleasanton's Kottinger Ranch water storage tank site. The transition station for PG&E's proposed project in the Pleasanton area would be located on property owned by Foley Intervenors.
The underground segment begins at the transition structure and traverses the ridge to the existing Kottinger Ranch water tank in south Pleasanton. After passing the water tank, the route continues down an existing paved road and into city streets. PG&E's engineering design for the route through city streets is set forth in Exhibit 3, Tab A. PG&E's proposed route would travel along Benedict Court, Smallwood Court, Hearst Drive, and Bernal Avenue. The section of Benedict Court on the proposed route is approximately 1,100 feet in length. The Smallwood Court segment is approximately 300 feet in length. The Hearst Drive segment is approximately 2,500 feet in length and the Bernal Avenue segment is approximately 4,300 feet in length. Many segments of these streets have homes only on one side of the street. PG&E indicates that the project would be constructed on the side of the street away from homes, wherever possible. The underground segment would continue along Bernal Avenue until it reaches Vineyard Substation. As proposed, the line will cross the Arroyo del Valle waterway by a horizontal dry boring, adjacent to the Bernal Avenue Bridge.
The underground segment would be constructed within a duct bank, consisting of nine PVC pipe ducts, encased in concrete. The duct bank would also include a duct to carry fiber optic cable. At intervals along the underground segment, splice vaults would be installed to allow for easier installation and maintenance. The transmission cable would be pulled through the ducts and spliced in the vaults.
4.2 Dublin/San Ramon and Livermore Area Proposed Project
In the Dublin/San Ramon area, PG&E proposes to construct a new Dublin substation, located three miles north of Interstate 580 and one mile east of Tassajara Road in Contra Costa County. In the North Livermore area, PG&E proposes to construct a new North Livermore substation, located three miles north of Interstate 580, just west of the intersection of May School Road and North Livermore Avenue. In order to serve these new substations, PG&E plans to install 7.9 miles of new 230 kV overhead double-circuit transmission line in its existing easement (which is currently vacant).
PG&E's proposed Dublin substation would be located on a five acre parcel just north of its existing right-of-way on rolling rangeland used for cattle grazing. This remote location is north of approved development within Alameda County, and south and east of approved development in Contra Costa County. Initially, no landscape screening is proposed for PG&E's proposed Dublin substation. PG&E estimates that it may be 10 to 15 years before its proposed Dublin substation site becomes surrounded by residential development.
The North Livermore substation would be identical to the Dublin substation in terms of the size, layout, and equipment but it would be constructed inside an earthen landscaped berm, with a precast concrete wall structure and vegetation appropriate for the setting. The substation would be set back approximately 60 feet from North Livermore Avenue to allow for any future widening of the roadway. The setback would also accommodate the length of driveway required to handle a mobile tractor trailer in the event of a transformer exchange, which would allow the normal traffic flow on North Livermore Avenue to be uninterrupted.
The total distance between the Contra Costa-Newark line and PG&E's proposed Dublin substation is 6.9 miles.6 The transmission line PG&E proposes would connect to the Contra Costa-Newark transmission line north of the City of Livermore and terminate in the west at the proposed Dublin substation. Beginning at the tap point on the Contra Costa-Newark line, the first four miles of PG&E's proposed transmission line traverse due west. At the 4-mile mark, the route turns 20 degrees in the southwest direction. It continues 0.7 miles and then makes a 12 degree turn north and continues for 1.3 miles. The route makes a final 8 degree turn north, heading almost due west, and traverses 0.9 miles before terminating at the Dublin substation site. The towers are expected to be lattice towers compatible with the existing Contra Costa-Newark line. The route crosses primarily grassland within a vacant PG&E right-of-way (which would need to be expanded from 75 to 120 feet in width for the project).
To serve the North Livermore substation, at 2.1 miles west of the Contra Costa-Newark tap point, a line turns south on North Livermore Avenue. It continues south one mile to the proposed North Livermore substation location just west of May School Road.
4.3 Phase 2 Proposed Project
As proposed, Phase 2 would directly connect the Dublin and North Livermore substations to the Tesla Substation, which is located in the Central Valley, southeast of Altamont Pass. When the transformer loading at the North Livermore and Dublin substations approaches the current carrying limit of the Contra Costa-Newark 230 kV circuit, PG&E proposes to construct approximately 10 miles of double-circuit, looped-configuration transmission line to the Tesla Substation in its existing vacant easement.7 Towers for this portion of the line would be tubular steel pole construction.
PG&E's existing 75 foot wide easement would need to be widened to 120 feet to accommodate Phase 2. Phase 2 would use the easternmost 10 miles of the existing easement, from its intersection with the Contra Costa-Newark 230 kV transmission line near Vasco Road to its origin at Tesla Substation. This easement traverses gently to moderately sloped grazing land, mostly encumbered with windfarms through the Altamont Hills. Some relocations of this easement may be necessary at the Republic Services Group Landfill8 at Vasco Road and within some of the windfarm development where there are encroachments on PG&E's easement.
