5. Description of Alternatives Studied⁹

During the environmental review process, the Commission studied alternative transmission line routes, alternative substation locations, the possibility of local generation to defer need for the project, and a "no project" scenario. As a part of the alternatives evaluation process, 27 potential alternative routes or methods of providing the required increase in electricity to the region were evaluated. Fourteen alternatives were eliminated because they did not offer significant environmental advantages over PG&E's proposed project or because they were not feasible.

In the Pleasanton area, the Commission studied five alternative routes (S1, S2, S2A, S4, and S5) in various configurations to connect a 230 kV transmission line from the Contra Costa-Newark #2 transmission line to Vineyard Substation and a local generation alternative. In the Dublin/San Ramon area, the Commission studied one alternative Dublin substation site (D1) and two alternative routes (D1 and D2) to connect a new Dublin substation by a 230 kV transmission line to Contra Costa-Newark #2. In the North Livermore area, the Commission reviewed two alternative substation sites (L1 and L2) and five alternative routes or configurations (L1, L2, P1, P2, and P3) to connect a new North Livermore substation by a 230 kV transmission line to Contra Costa-Newark #2. For Phase 2, the Commission reviewed one alternative transmission route (Stanislaus Corridor) and a switching station alternative. ¹⁰ Each alternative is described below.

5.1 Pleasanton Area Alternatives

All Pleasanton area alternatives (with the exception of the local generation option) include upgrades to the existing Vineyard Substation. New structures would be erected within the existing fenced perimeter of the Vineyard Substation to accommodate the new 230 kV transmission line connections. New equipment would include circuit breakers, switches, bus work, transformers, control and power cables, relay, and communication equipment.

5.1.1 S1 (Vineyard-Isabel-Stanley) Alternative

In this alternative, the Contra Costa-Newark line would be tapped in the Tesla-Newark Corridor within Sycamore Grove Park. The transmission line would be installed overhead from the Tesla-Newark corridor to the southwest corner of Highway 84 and Vineyard Avenue. This portion of the new 230kV line would generally follow the existing 60kV route. The overhead/underground transition point would be located about 100 feet southwest of the corner of Highway 84 continuing straight north to the point where it meets Vineyard Avenue. The underground line would continue on the south side of Vineyard Avenue to Isabel Avenue. It would be installed overhead along the west side of Isabel to Stanley Boulevard, then turn west and be installed overhead along the north side of Stanley Boulevard. It would cross Stanley Boulevard into Vineyard Substation, just before Bernal Avenue. This alternative is about 6.6 miles long with 1.1 miles underground.

5.1.1.1 "Improved Isabel-Stanley"¹¹

The improved Isabel-Stanley route builds off of the S1 alternative but would place the transmission line underground along Isabel Avenue. The Pleasanton Parties did not identify specifically where the underground line would be placed along or within Isabel Avenue. Undergrounding along Isabel Avenue is designed to mitigate the adverse, but less than significant, visual impacts of an overhead line on Livermore residents.

5.1.2 S2 (Vineyard Avenue) Alternative

This alternative would follow the same path as S1 until Isabel Avenue. Where S1 turns north onto Isabel Avenue, S2 would remain underground, crossing Isabel Avenue and continuing underground along Vineyard Avenue, using either New or Old Vineyard Avenue¹², to Bernal Avenue. Where Vineyard Avenue meets Bernal Avenue, the line would turn north on Bernal Avenue (still underground), and into the Vineyard Substation as it would in the proposed route. This alternative would be about 5.5 miles long; the first 1.5 miles would be installed overhead and the remainder underground.

As described in the Exhibit 1003, this alternative can travel on either New or Old Vineyard Avenue. The FEIR explored locating the underground line along New Vineyard Avenue or locating the underground line within the Old Vineyard Avenue roadway (which will become a limited-access roadway with recreational and local access uses).

5.1.3 S2A Alternative

This alternative segment was developed to eliminate the significant visual and recreation impacts of the portions of the S1 and S2 alternatives that are located in the Sycamore Grove Park. S2A can be combined with the S1, S2, and S2/S5 alternatives and replaces the overhead portion of S2. S2A would be installed completely underground, except for an overhead-to-underground transition station adjacent to the Tesla-Newark corridor near the Del Valle Water Treatment Plant. The S2A alternative would begin at the existing Contra Costa-Newark transmission line southwest of the water plant, with a transition station located on private property. It would require an approximately 1-mile long transmission line to reach the S1/S2 route adjacent to Sycamore Grove Park. Two feasible options were considered for the southern most portion of this one mile route, but both options would be the same in the northernmost 0.6 miles. The options for installation of the southern 0.4 miles are to install it overhead or underground west of Foley Road. The FEIR explored placing this portion underground within Foley Road but determined that it would be infeasible due to conflicts with existing subsurface drainage and water collection systems operated by the Zone 7 water treatment plant. In the next 0.6 miles, the transmission line would be installed underground, west/northwest of Foley Road and outside of the roadway right-of-way. In this manner, the line would not conflict with Zone 7's existing or future pipelines, nor would the stability of any portion of the road be jeopardized. Where S2A meets the S1 and S2 routes, S2A would continue underground, following whichever route it is combined with.

5.1.4 S4 (Eastern Open Space) Alternative

This alternative would follow PG&E's proposed route overhead from a tap in the Tesla-Newark Corridor, 2.2 miles to a point where S4 would turn northeasterly away from PG&E's proposed route. The S4 route would continue northeasterly overhead for 1.5 miles, then transition to underground for the last 0.8 mile north to Vineyard Avenue. At this point, the S4 route would turn west on Vineyard Avenue, still underground, and follow the S2 route along Vineyard Avenue and Bernal Avenue into the Vineyard Substation. The total length of this alternative (from the Tesla-Newark tap to the Vineyard Substation) would be about 6.6 miles. The S4 alternative could also be combined with the S5 alternative instead of following the S2 route into Vineyard Substation.

5.1.5 S5 (Quarry) Alternative¹³

S5 provides an alternative routing from New (or Old) Vineyard Avenue to the Vineyard Substation. S5 crosses through quarry property and can be combined with parts of the S2A/S2, and S4 alternatives. S5 could begin in various locations, depending on the route it is combined with. S5 would essentially begin from either New (or Old) Vineyard Avenue and turn north at the location where the existing 60 kV line crosses Arroyo del Valle Creek, just across from the future Neal Elementary School. The line would be installed underground at the creek crossing by means of an open-trenched crossing which would end at a transition station located on quarry land where the line would be brought overhead. From this half-acre fenced transition station, three tubular steel transmission poles would be installed on quarry land, and a fourth pole would be located north of Stanley Boulevard. Approximately 8 to 10 more poles would be located along the north side of Stanley Boulevard to the west of the crossing at the quarry entrance, then the line would cross back to the south into the existing Vineyard Substation.

5.1.6 Local Generation Alternative

At the time the DEIR was prepared, there were three potential generation projects in the Tri Valley area, two in Pleasanton and one in Livermore. Each would involve construction of a natural gas turbine power plant of less than 50 MW. If constructed by mid-2002, the Pleasanton projects could defer the Vineyard Substation upgrade and associated transmission upgrade for one to two years, depending on demand growth.

5.2 Dublin/San Ramon Area Alternatives

5.2.1 D1 (South Dublin) Alternative

The D1 alternative would require a transmission line of about 3.1 miles with about 0.8 mile underground, as well as a new five-acre substation. The 230 kV transmission line connection would originate at Vineyard Substation in the south. The overhead portion of the 230 kV transmission line to the D1 substation would start from Vineyard Substation, cross Stanley Boulevard, head north until it reached the north side of the paved east-west roadway into the gravel quarry area. There the route turns east for 0.25 miles, then turns north for 0.35 miles. At this point, the route follows El Charro Road through the gravel quarries and continues to the south side of the I-580 interchange. Approximately 15 tubular steel transmission poles would be required for the overhead portion of the route.

Just south of I-580, the transmission line would transition to underground at a half-acre transition station. It would turn west to follow the south side of the Caltrans right-of-way, and then turn north and cross beneath the freeway (by means of a bored crossing) one half mile west of Fallon Road. From the north side of the freeway, the line would go straight north into the D1 substation one half mile west of Fallon Road.

The D1 substation would be constructed on five acres of currently vacant land in a commercially-zoned area between Fallon and Tassajara Roads, about 1,000 feet north of the I-580 freeway and 2,600 feet west of Fallon Road and immediately south of (and adjacent to) the future extension of Dublin Boulevard. This location was selected because it is in the only commercially-zoned portion of the Dublin Ranch development; all the property to the north will be residential. The FEIR recommends a mitigation measure (L-14) that would require screening of the substation to minimize visibility of the substation within the commercial area.

5.2.2 D2 (Dublin/San Ramon) Alternative

For the D2 alternative, PG&E's proposed Dublin substation would be constructed at PG&E's proposed location but the substation would be fed from the west (from the existing San Ramon Substation). The 230 kV line from Dublin to San Ramon would follow PG&E's vacant easement. Approximately one mile of the westernmost part of the route (from the ridgeline west into the San Ramon Substation) would be installed underground. In addition, the San Ramon-Pittsburg line (a single circuit 230 kV line) would need to be reconductored along its entire length (approximately 20 miles) along with some minor upgrades to the San Ramon Substation to increase power into the substation.¹⁴

5.3 North Livermore Area Alternatives

5.3.1 L1 (Raymond Road) Alternative

L1 would start at a tap to the Contra Costa-Newark line at the northeast corner of Ames Street and Raymond Road. A transition station would take the line underground at that corner, and the line would run underground to the west along Raymond Road for 1 mile to the corner of Raymond Road and Lorraine Road. This route follows the north side of the Alkali Sink Preserve where a unique assemblage of sensitive plant species, including the endangered palmate-bracted bird's beak, grows. The L1 substation would be located just northeast of this corner, immediately east of the farm/barn property that is just north of the Raymond/Lorraine Road corner. The substation itself would be identical to that proposed by PG&E at the North Livermore Road site: it would be five acres with berms, vegetative screening, and walls as required to protect views.

5.3.2 L2 (Hartman Road) Alternative

The 230kV transmission line route would be the same as for S1, but rather than turning west on Stanley Boulevard, the line would continue north for an additional 1.7 miles along the Highway 84 corridor to the I-580 junction. Between Stanley Boulevard and Jack London Boulevard, the line would be installed overhead and then from Jack London Boulevard north it would be underground. The underground line would turn west to a location just west of the Water Reclamation Plant and east of the end of the airport runways, cross Airway Boulevard at an angle to the northeast, then turn north again along Kitty Hawk. The line continues underground beneath I-580 approximately one to 1.3 miles north of I-580 to a North Livermore substation study zone in the southwest corner of the North Livermore development area, near Las Positas College.

The total length of this alternative (from the Tesla-Newark Corridor the L2 substation Site) is about 7.3 miles, with 3.6 mile underground.

Due to the topography (relatively steep hillside) of the substation site area, the EIR evaluated a substation "study zone" for the L2 alternative that included the hillside and the flatter area to the north. The southern portion of the study zone is within the City of Livermore, and the northern portion is in unincorporated Alameda County. The whole study zone is adjacent to and immediately southeast of the future Hartman Road. The substation would occupy a five-acre site in the study zone.

5.3.3 P1 (Variant on the Proposed Project)

This alternative is identical to PG&E's proposed project, except that the one mile of north-south 230 kV transmission line along North Livermore Road would be installed underground. Two overhead/underground transition structures (one for each circuit) or a transition station would be located just southwest of the corner of North Livermore Road and Manning Road.

5.3.4 P2 (Variant on the Proposed Project):

This alternative encompasses P1, and would also require PG&E to install the first 2.8 miles of the transmission line, from the Contra Costa-Newark tap point heading west, underground.

5.3.5 P3 (May School Road)

This underground route would be 2.4 miles long and would follow May School Road, east from the PG&E's proposed North Livermore substation to the Contra Costa-Newark transmission line (where a transition structure would be installed). Because of landslide concerns at the easternmost point of this route, the route was modified slightly in the FEIR by moving the easternmost part slightly to the north and utilizing more stable and less steep terrain.

5.4 Phase 2 Alternatives

5.4.1 T1/Stanislaus Corridor Alternative

A new 230 kV double circuit line would be constructed from Tesla Substation to the tap point of the selected Pleasanton area alternative. This route would be about 14.2 miles long (if combined with the S1 or S2 alternatives) or 17.3 miles long (if combined with PG&E's proposed route or the S4 alternative). The Stanislaus Corridor is currently occupied by two parallel lattice tower lines constructed around 1910 that are not currently in use. As part of this alternative, the parallel towers would be replaced with one set of tubular steel towers. At Tesla Junction, where the Stanislaus towers continue east across the Central Valley, the new line would turn northeast, for 2.1 miles into the Tesla Substation, paralleling an existing 115kV lattice tower line. This alternative would use existing transmission corridors along its entire length and would replace the 10 miles of PG&E's new Phase 2 Northern Corridor.

5.4.2 T2/Switching Station Alternative

During Phase 1 of the project, the Vineyard, Dublin and North Livermore substations would all be connected to the Contra Costa- Newark #2 line. The Phase 2 switching station alternative would involve construction of a switching station to allow direct connection of the new 230 kV transmission lines (proposed or alternative routes) in the Pleasanton area to the existing Tesla-Newark 230 kV transmission line. The existing Tesla-Newark line, while also a 230 kV line, has a higher rating (allowing it to carry more power) than the Contra Costa-Newark line. Power flow modeling by the ISO verifies that Tesla-Newark line is capable of supplying the switching station and the Vineyard and Dublin Substations without overloading.

¹³ This alternative was originally eliminated from consideration in the DEIR due to concerns about limiting availability of gravel resources, potential conflicts between quarry operations and transmission lines, concerns about cliff instability, and visibility of overhead transmission lines from Shadow Cliffs Regional Recreation Area. Based on comments on the DEIR, this route was reconsidered, modified, and included as an alternative in the FEIR. Because this route did not result in significant impacts, recirculation of the EIR was not required. (See D.01-05-077, p. 12 and Conclusion of Law 6.)