Pacific Gas and Electric Company (PG&E) has completed a temporary microgrid designed to provide electricity to shared community resources and neighborhoods in downtown Colfax during future Public Safety Power Shutoff (PSPS) events. PG&E is also developing a temporary microgrid in Foresthill.

A temporary microgrid is a grouping of electric lines and infrastructure that PG&E can quickly isolate, or island, from the larger electric grid. PG&E can safely provide electricity to customers within the microgrid when the surrounding lines need to be turned off for safety. Though each temporary microgrid will vary in size and capability, they all include:

•    Devices that can disconnect the temporary microgrid from the larger electrical grid

•    Pre-determined space and connection equipment for a backup generator

“The microgrids in Colfax and Foresthill are among the many sites PG&E is developing across our service area in 2021 as a part of the company’s comprehensive actions to reduce wildfire risks across our system and minimize the effects of public safety outages on our customers and communities,” said Debbie Powell, interim head, Electric Operations, PG&E.

The Colfax temporary microgrid was completed and made operationally ready in December 2020; PG&E intends to upgrade the site in 2021 to allow for faster and more stable connections of temporary generators.

The new microgrid in Colfax is located in the parking lot behind the Colfax Railroad Junction building (7 North Main Street) at the corner of North Main Street and Grass Valley Street, in downtown Colfax. PG&E will be able to rapidly connect mobile generators to the site, allowing a fire station, school, bank, post office, city administration building, pharmacy, gas stations, markets, and restaurants among other businesses, community services and some residences to remain energized during future PSPS events in the area. The Colfax temporary microgrid energization area includes approximately 391 customers in communities east of Interstate 80 near North Main Street, south of Gearhart Street and north of Treasureton Street.

The new microgrid generation site in Foresthill, currently under development and anticipated to be complete by May 2021, is located adjacent to the PG&E substation at 5860 Sunset Drive off of Foresthill Road. The site will keep power flowing to Foresthill High School, a water agency, wellness center, church, gas station, market, post office, bank, and some other businesses, facilities and community services during future PSPS events impacting the area. The Foresthill temporary microgrid energization area includes 14 PG&E customers in the general vicinity of Foresthill Road, extending between Baltimore Mine Road and Racetrack Street.

PG&E currently has six temporary microgrid generation sites ready to use during PSPS events throughout its service area, including the Colfax site. Nine additional sites, including Foresthill, are under development.

These sites were identified and selected through an extensive process involving the analysis of prior and potential future PSPS events, along with community feedback, overall feasibility and other utility work in the region that could reduce PSPS impacts.

While performing this critical safety work during the COVID-19 pandemic, PG&E expects crews to maintain proper social distancing recommendations and wear protective equipment to help safeguard the health and safety of themselves and the general public.

PG&E customers in the vicinity of the construction sites will receive an automated, courtesy phone call from PG&E notifying them of the work taking place.

Customers who are within the temporary microgrid energization areas will receive a separate communication from PG&E, notifying them of their inclusion in the microgrid and informing them of how it will operate during a PSPS event.

Temporary Microgrid Operational Considerations

While PG&E intends to make every effort to operate these microgrids during a PSPS event, PG&E is not able to guarantee electricity to all customers potentially served by a temporary microgrid during all PSPS conditions or scenarios due to a variety of operational considerations. These include:

•    Hazardous conditions such as an ongoing wildfire or weather conditions that could pose a fire risk if lines were energized.

•    A large PSPS event or multiple emergencies happening simultaneously that require prioritizing generation to critical locations.

•    Equipment damage or mechanical failure.

Other PG&E Wildfire Resiliency Efforts

Ongoing safety work to enhance grid resilience and address the growing threat of extreme weather and wildfires across PG&E’s service area continues on a risk-based and data-driven basis.

This includes expanding the network of enhanced weather technology, installing stronger poles and power lines, doing targeted undergrounding, and conducting enhanced vegetation management.

In addition to deploying temporary microgrids, which are primarily designed to keep shared community services energized, PG&E has made a number of improvements to reduce the effects that PSPS events have on customers, including:

•    Sectionalizing and Grid Reconfiguration: Installing more than 600 additional sectionalizing devices in 2020 capable of re-directing power and limiting the size of outages. PG&E also analyzed its grid configuration to ensure as few customers as possible are affected by future PSPS events.

•    Substation Microgrids: In some PSPS events, PG&E must turn off power to higher-voltage transmission lines for safety. Transmission-level shutoffs generally impact a larger number of customers—some in areas that are not directly experiencing the severe weather conditions. PG&E’s substation microgrid solution is intended to reduce this impact.

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