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5.20 Dry Utilities

from on-site renewable energy generation (PDF 21-3). The GHG emissions associated with
energy use (electricity and natural gas) were estimated based on these assumptions. For the
reasons discussed above, implementation of the Project would result in a less than significant
impact to electrical services or facilities during construction or operation.

Through coordination with SCE, two options were developed for bringing the additional
electrical capacity: (1) upgrading the existing Bailey Substation located on an SCE-owned
parcel within the southwestern corner of the Project site (Exhibit 5.20-2, Centennial Project
– Dry Utility Improvements) and/or (2) upgrading the Gorman Substation and retrofitting
the associated existing overhead transmission lines between the Gorman Substation and the
Project site to handle the higher load. Upgrade of the Bailey Substation is considered the
more likely solution; however, both options would continue to remain open until later stages
of the site development process. The timing of the upgrade to the Gorman Substation and
associated overhead lines or the Bailey Substation would be determined through ongoing
coordination between SCE and the Project Applicant/Developer. In either event, these
improvements would occur entirely on lands and/or easements owned by SCE, and
therefore would not be on the Project site. The option to upgrade the Bailey Substation
(option 1) or Gorman Substation and overhead lines (option 2) to provide additional
electrical capacity to the initial development of the entire Project is described in further
detail below.

The Bailey Substation is a transmission relay substation, and is currently not configured for
the distribution of voltage facilities that would be required to serve the Project. The site of
the Bailey Substation is large enough (1.5 acres) to accommodate the required upgrade and
it could be configured to serve the Project. The Bailey Substation upgrade would include the
installation of a distribution transformer to carry sufficient load to the Project. Distribution
voltage would then be extended to the Project on the existing overhead pole line along
SR-138 or routed northerly overhead or underground around Quail Lake within the Project
limits for the initial phases of development, then placed underground throughout the
Project. This location, if upgraded as described, would provide sufficient electrical capacity
to serve initial Project site development. The update of the Bailey Substation would not
require retrofitting of any overhead lines. The upgrade of the Gorman Substation would
require retrofitting of overhead lines as described further below.

The Gorman Substation, located approximately 3.6 miles northwest of the site, is currently
configured for distribution voltage. However, this substation would require the addition of
one or more additional transformers and the reconstruction of existing overhead power
lines along Gorman Post Road from the substation to the Project. At a point just west of the
Project boundary, the overhead facilities would take either direction along SR-138 or the
northerly route around Quail Lake. It should be noted that, if the Bailey Substation upgrade
were implemented, no upgrades to the Gorman Substation and its associated overhead lines
or other off-site substation and overhead facilities would be necessary to serve any portion
of the Project.

Off-Site Impacts

To provide adequate electricity for the Project, two options were developed for bringing the
additional capacity to serve the western portion of the Project site: (1) upgrading the existing

R:\Projects\PAS\CEN\000306\Draft EIR\5.20 Dry Utilities-051117.docx 5.20-12 Centennial Project
Draft EIR