Critical 70KV Transmission Line from Yosemite National Park’s boundary to Highway 140 Powerhouse to be Replaced through GAOA Funding

NPS / PG&E

Yosemite National Park, with funding from the Great American Outdoors Act (GAOA), will replace critical failing electrical infrastructure and a high voltage transmission line that serve multiple areas in Yosemite National Park including: Yosemite Valley, Turtleback emergency communications hub, and the Wawona Tunnel distribution systems.

The 5.1-mile transmission line and its 54 supporting metal towers, insulators, and conductors fail to meet current regulatory requirements. The primary transmission line has failing parts and has accrued damage from lightning strikes, rockslides, fires, and falling trees.

Without this project the power provider for the park, Pacific Gas & Electric (PG&E), could turn off power to this deficient line. If the line fails or is disconnected by PG&E, park communications systems would be unavailable and approximately 20,000 visitors, residents, concessionaires, and park partners would be negatively impacted during the summer months.

Project at a Glance: This $9.319 million project will replace a high-voltage transmission line that serves multiple areas in Yosemite National Park. Replacement of the line will allow the park to continue to provide power, lighting, and heat to approximately 20,000 visitors, residents, concessionaires, park partners, and staff. The project will minimize power outages and improve safety for the park, including powering central radio and cell towers for critical and emergency communications; including the medical clinic.

What are the Benefits: This project will increase power reliability for many areas of the park including: Ahwahnee Hotel, Yosemite Lodge at the Falls, Curry Village, employee housing, and the new work at Bridalveil Falls. Bringing the line to updated Federal Energy Regulatory Commission (FERC) and California Public Utilities Commission (CPUC) standards will allow the NPS to reinitiate discussions with the commercial power company to take ownership of the transmission line, therefore being responsible for its maintenance and reliability.

Project Details

Anticipated Start Date*: Fall 2021
Anticipated Completion*: Winter 2021
Project Costs*: Approximately $9.319 million
Visitor impact: There will be no visitor impact during construction.

*These are estimates and subject to change

Project Purpose and Goals

First protected in 1864, Yosemite National Park welcomes millions of visitors each year and is best known for its waterfalls, ancient giant sequoia trees, abundant wildlife, and cliffs, like Half Dome and El Capitan. To ensure visitor enjoyment and protection of these areas, this project will:

• Replace the non-compliant 70KV transmission line that provides electrical power to multiple areas in Yosemite National Park

• Prevent a major long-term power outage to all of Yosemite Valley, the Wawona Tunnel, and the park’s Turtleback emergency communications system hub

• Update critical electrical components

• Correct $9.319 million of deferred maintenance repairs

• Replace damaged and rusted line towers that pose life-threatening safety risks to electricians

• Curtail multiple annual power outages for Yosemite Valley

• Remove a significant fire hazard and safety concern by replacing outdated equipment and removing vegetation hazards

• Decrease NPS spending associated with regular repairs

Current Status

This project was deemed substantially complete as of December 7, 2021. The 90 year-old transmission line powering the entire Yosemite Valley received $9 million Critical Repair and Replacement Funding through GAOA Fund.