A fast-growing downtown district needed additional electrical capacity to support rising demand. In response, the utility advanced a downtown repowering initiative — a series of electrical infrastructure improvements that have nearly doubled capacity in the historic area.
Stanley Consultants designed the new downtown substation and also provided permitting, community support, procurement and construction support services. The broader program — outside of Stanley Consultants’ scope — included upgrading network distribution feeder circuits, adding a 70-MVA transformer to an existing substation and rebuilding another downtown substation by the end of 2026. The substation supports load transfers needed to complete upgrades at the network substation and facilitates future conversion of multiple 69-kV facilities to 138-kV operation.
The 1.46-acre parcel was acquired in 1999 with future electrical distribution upgrades in mind. During design, subsurface investigations identified a 72-inch stormwater drain and an additional water main. To accommodate the existing infrastructure, the water main was relocated, and the substation footprint was reduced to 0.87 acres, while preserving future access to the stormwater drain. To support the compact site, the design uses gas-insulated switchgear (GIS), which requires significantly less space than conventional air-insulated switchgear.
Three 70-MVA power transformers were installed on 45-foot-deep piers so the stormwater drain could be excavated if needed. Removable wall sections, a grounding system designed to remain safe if part of the site required removal and ground wells backfilled with bentonite clay were all incorporated to meet grounding requirements.
Aesthetic considerations and neighborhood feedback also helped to shape the project. Stanley Consultants managed subcontractors as the utility worked with the community on wall designs, landscaping, native grasses and streetscape elements to fit in with the surrounding historic district. The GIS substation includes a 30-foot-tall equipment building, an integrated 12-foot-high enclosure wall and motorized sliding entrance gates within the colorful wall design.
Transmission poles were installed to route underground circuits into the GIS switchgear, while taking care to protect heritage oak trees. Walkways, benches, decorative lighting, bike racks, rain gardens, native plantings and other landscape features were added to make the site more compatible with the surrounding neighborhood.
The new substation supports downtown energy needs with a small footprint and enables an existing downtown substation to be removed from service for full reconstruction, furthering the broader downtown repowering initiative.