Pacific Gas and Electric Co. (PG&E) has identified more than 80 cases of damage or hazards found on power lines that had been de-energized for public safety because of the recent severe wind event. Any of these could have potentially led to a wildfire had the lines not been turned off during the Public Safety Power Shutoff (PSPS) event that started on Sept. 7, 2020.
Although conducting a PSPS event is a tool of last resort for the PG&E, the goals of the program are to not have electrical equipment start any catastrophic wildfires and to prioritize public and customer safety.
In a report submitted to the California Public Utilities Commission (CPUC), the PG&E shared:
- Wind gusts in excess of 50 mph were recorded at weather stations in 14 different counties in the PG&E's service area, including:
- A 66-mph gust in Butte County
- A 66-mph gust in Sonoma County
- A 62-mph gust in Kern County
- How the PG&E's website and contact centers successfully provided information to millions of customers without any difficulties or delays
- How 50 Community Resource Centers (CRCs) provided water, bathrooms, and device-charging to thousands of customers whose power had been turned off for public safety
- How new weather technology and mitigation measures enabled the PG&E to execute a PSPS that affected approximately 50% fewer customers than a comparable weather event would have in 2019
- How the PG&E was able to restore electric service to 97% of all customers who could be safely restored on Sept. 9, within 12 daylight hours of the severe weather clearing, and to all customers served by accessible circuits on Sept. 10
"We have worked diligently to improve PSPS by integrating enhanced weather technology, boosting our coordination with counties and state agencies, and making sure customers get timely and accurate information," said Michael Lewis, the PG&E's interim president. "Still, we know turning off the power represents a significant hardship for our customers. Please know that we don't take this decision lightly and we will only initiate a PSPS as an option of last resort when severe weather that could cause a wildfire makes it absolutely necessary for public safety."
Because of preparation and mitigation strategies, the Sept. 7 to Sept. 10 PSPS event affected approximately 50% fewer customers than a comparable de-energization in 2019. This was the result of improved meteorological analytic tools, distribution sectionalizing devices, temporary generation including microgrids, and the ability to island the Humboldt Bay Generation Station to provide local power.
This PSPS event was based on a forecast of dry, hot weather with strong winds and dry fuel on the ground that posed significant wildfire risk. After getting notifications starting two days ahead, approximately 172,000 customers in 22 counties had their power turned off for public safety late in the day on Sept. 7. Once the severe weather subsided, the weather "all clear" was given early on Sept. 9.
After PG&E crews patrolled thousands of miles of transmission and distribution (T&D) power lines — a necessary step to see if the strong winds had caused damage or tossed hazards such as tree limbs into the lines — more than 97% of customers who could take service had been restored by nightfall on Sept. 9. The remaining customers were restored on Sept. 10. Because of unsafe flying conditions caused by smoky conditions and gusty easterly winds, the PG&E was unable to use a portion of its helicopter fleet to conduct aerial inspections. In all, approximately 2700 PG&E personnel participated in restoration work aided by another 300 employees in the PG&E's Emergency Operations Center.
These inspections revealed more than 80 instances of weather-related damage and hazards in the PSPS-affected areas. This included 59 instances where PG&E lines or other electric-system components were damaged by vegetation (17) or wind (42). Damages, such as a wire down or a fallen pole, are conditions that occurred during a PSPS event, resulting in necessary repairs or replacement of PG&E assets. Additionally, there were 24 instances where a hazard was found. These, such as a tree limb intertwined in a power line, are conditions that might have caused damage had the line not been de-energized.
Below are some examples of what was found as PG&E crews inspected lines prior to re-energization. If a PSPS had not been executed, these types of damages could have caused potential wildfire ignitions.
- In Concow in Butte County, a tree fell into a wire and knocked it to the ground
- In unincorporated El Dorado County, multiple tree limbs fell on a 21,000-V power line
- In Colfax in Placer County, a broken crossarm was found, which could have resulted in the power line sagging or falling
- In unincorporated Shasta County, a broken pole was found during patrols
During the PSPS, the PG&E opened 50 CRCs in 18 counties. Each center offered an ADA-accessible restroom and hand-washing station, medical equipment charging, device charging, Wi-Fi, bottled water, and snacks. Because of COVID-19 safety protocols, many of these CRCs were microsites (open-air tents) or mobile sites supported by van. Visitors were required to wear masks and stay 6 ft apart. For safety and customer convenience, the PG&E provided more than 1300 grab-and-go bags, which included water, snacks, and a charging device.
The PG&E is applying lessons from past PSPS events and this year will be making events smaller in size, shorter in length, and smarter for customers.
- Smaller in size: During this PSPS event, because of the use of temporary generation, including microgrids and the islanding of a power plant, about 70,000 customers remained energized who would have otherwise lost power. Temporary generation supported nine critical facilities including ICU hospitals and COVID-19 care centers. Sectionalizing devices on 73 circuits allowed the PG&E to de-energize portions of a circuit, versus the entirety of the circuit, keeping approximately 53,000 customers in power.
- Shorter in length: Despite heavy wildfire smoke, 97% of all customers who could be safely restored were restored on Sept. 9, within 12 daylight hours of the severe weather clearing, and all customers served by accessible circuits were restored on Sept. 10.
- Smarter for customers: Before this PSPS event, the PG&E significantly updated its website and established a new emergency website for scalability and stability. The PG&E's main webpage, pge.com, has the capacity to serve 12 million hits per hour, and the PG&E's emergency website, which maintains the PSPS event update information, has the capacity to serve 240 million hits per hour. During this event, pge.com's hit rate peaked on Sept. 6 at 7 p.m. with approximately 2.45 million hits per hour, and the emergency website with PSPS update information peaked on Sept. 7 at 7 p.m. with approximately 1.69 million hits per hour.
More than 10,300 vulnerable customers, who take part in the PG&E's Medical Baseline program, had enhanced notifications from the PG&E, including 1037 cases where a PG&E employee knocked on their door prior to the PSPS. Additionally, through the California Foundation for Independent Living and other community-based organizations, support included 550 back-up batteries, 174 food vouchers, 91 hotel vouchers, and transportation for nine customers. In partnership with five local food banks serving 11 counties, the company arranged more than 9000 boxes of food replacement for families who experienced food loss during the event.
