Treasure Island and Yerba Buena Island Electric System Improvements Improvements Will Reduce Blackouts and Enhance System Reliability
The San Francisco Public Utilities Commission (SFPUC) is the energy provider on Treasure Island and Yerba Buena Island. The Treasure Island Development Authority (TIDA) owns the electric infrastructure, which the SFPUC uses to deliver power to residents and businesses on both islands.
Typically, electric infrastructure has a lifespan of 25-30 years. The infrastructure on Treasure Island and Yerba Buena Island, which TIDA inherited from the U.S. Navy, ranges from 40-50 years in age. The age of the system and condition of the equipment make the island vulnerable to power outages that a more modern system would not experience or which would be limited to a smaller area.
Power outages on the island arise when something interrupts the distribution of electricity through the system. These “faults” can arise from a variety of causes, including fallen tree limbs, birds or other wildlife, and malfunctioning equipment.
Several improvements have been made in the past 18 months to improve the system reliability and more are scheduled for the year ahead.
These near term infrastructure investments will enhance system reliability, decrease the number of blackouts, and reduce the duration and number of customers affected when there is a power outage.
TIDA and the SFPUC have been pursuing four avenues to improve system reliability – preventing faults that could lead to an outage, improving the ability of the system to minimize the impact of a fault, limiting any resulting outages
to only a portion of the island rather than the full island, and installing equipment that will help locate where a fault has occurred to speed system restoration.
In 2020 the SFPUC installed fault indicators and reclosers at many locations in the island distribution system. Fault indicators assist crews in determining where in the system a fault has occurred speeding power restoration while reclosers can both help the system to avoid service interruptions following certain minor faults and to limit outages to just a portion of the system when a fault occurs.
Also in 2020, Treasure Island Community Development (TICD), the master developer for Treasure Island, and the SFPUC began constructing a new switchyard and installing new switchgear to serve Treasure Island. This switchgear is scheduled to be energized in the last week of April. The former Navy switchgear is sensitive to system faults and does not effectively separate the existing system into geographically separate circuits. After additional work, the new switchgear will be capable of surviving certain faults that would cause the existing switchgear to fail resulting in an island-wide outage and will support the separation of the island geographically into separate circuits so that outages should be limited to the area served by an individual circuit rather than resulting in island-wide outages.
In addition to the projects initiated in 2020, TIDA and the SFPUC have identified additional priorities for improving system reliability in 2021. The table below describes the projects initiated and completed over the past year and additional improvements that are being planned and designed for implementation this year. TIDA and the SFPUC continue to evaluate additional opportunities for improving the resiliency and reliability of the electrical system on Treasure Island.
Outages in 2021
The work done in 2020 has had some success in limiting the geographic extent of outages. There have been three island-wide outages in 2021 – on April 6th, 11th & 16th – but there have been five other incidents where the extent of the outage was limited to just a portion of the island.
Questions?
Contact:
San Francisco Public Utilities Commission at:
(415) 554-3233 or email peter.gallotta@SFWater.org
Treasure Island Development Authority at:
(415) 274-0660 or email TIDA@SFgov.org
