Pacific Gas & Electric’s top executives and members of its post-bankruptcy board of directors faced a nearly five-hour grilling from the California Public Utilities Commission on Friday over the communications, planning and execution failures of its massive fire-prevention power outage earlier this month.
Amidst a public outcry over its handling of the five-day blackout of an estimated 2 million people, PG&E’s leaders had few successes to speak to, beyond the absence of fires. Instead, they offered apologies, explanations, and promises to prevent future breakdowns like the multiple website crashes and overwhelmed conference call systems that left customers and key government partners alike in the dark during the first days of the event.
CEO Bill Johnson’s statement that PG&E will be continuing public safety power shutoff (PSPS) events for the next decade or so drew a quick public outcry, and a quick explanation from the utility that it will reduce the scope and duration of those outages over time. Still, it’s going to take years to trim trees, harden poles, shield power lines, underground select circuits, and otherwise limit its fire risk profile to reach that goal.
But PG&E did report a handful of successes from its ongoing investments into technologies to limit the scope and duration of fire-prevention outages. Specifically, PG&E’s investment into grid sectionalization gear allowed it to restore tens of thousands of customers in the early stages of the blackout, Sumeet Singh, PG&E’s vice president of its Community Wildfire Safety Program, explained in a Friday presentation.
PG&E’s forecasting and data analysis appears to have accurately predicted just where high winds and on-the-ground conditions would lead to grid faults, he said. The utility is now integrating the field data from this month’s outage, including the 100 or more instances of bare wires coming into contact with tree limbs or other potential faults, to inform its analysis of future outages.
Real-world benefits from grid investments
Since last year, PG&E has installed about 160 sectionalizing devices to allow outages or faults in one area to be isolated while adjoining areas can be restored with power from other circuits.
“Those actually benefitted us during this event on October 9,” when PG&E was able to restore about 48,000 customers through circuit reconfiguration, allowing them to be left out of the next wave of outages the following day, Singh said.
Throughout the outage, PG&E was able to use this kind of grid reconfiguration to mitigate the outage’s effects to about 77,000 customers, he said. PG&E plans to install about 550 more sectionalizing devices over the next 12 months, which should add more flexibility and granularity to their use.
Singh also highlighted PG&E’s fire risk forecasting and data analysis, which it used to reduce the initial footprint of the outage, as well as predict the points on its grid that were most likely to present fire risk. PG&E integrated more than 10 years of historical outage data and more than 20 years of fire data to inform its ongoing predictive analysis of where faults were most likely to occur during this month’s extended winds, Singh said.
These predictions ended up closely correlating to where PG&E field crews discovered real-world downed wires, tree limbs blown into power lines, and other weather-related grid fire hazards, he said. While that doesn’t necessarily give PG&E tools to avoid cutting power to those portions of its grid, it does indicate that cutting the power was the right decision, he noted.
Singh explained how some pockets of customers served by its radial distribution grid system may be forced to undergo power outages even though they’re not in areas of high fire risk, using the city of Pinole as an example. While much of the city lies along the low fire-risk shoreline of San Francisco Bay, certain neighborhoods are connected to PG&E’s larger grid through single power lines crossing dry hills that had to be shut down during the outage, he said.
The roughly 4,000 customers left without power in this example couldn’t have been helped by grid sectionalizing equipment, since there’s no other safe power corridor to serve them, he noted. “This is where there is the potential to institute a microgrid solution,” he said. So far, PG&E’s efforts on this front have been limited to a handful of ‘resilience zone’ projects using backup generators to provide power to key city and community services.
But in light of the urgency of the fire threat, PG&E is examining the potential for backup generators or community microgrids to help bolster those pockets of its grid that may find themselves electrically isolated during a fire-prevention outage, he said.
The real-world challenges ahead
PG&E’s overall efforts are closely modeled on those of fellow California utility San Diego Gas & Electric, Singh noted. SDG&E has invested more than $1.5 billion in state-of-the-art fire prevention technology and programs over the past decade. It can now combine in-house forecasting expertise and granular control over sectionalized and networked distribution circuits to limit most outages to tens of thousands of customers, along with community outreach and support for those affected.
These “have been three pillars of success for SDG&E,” Elizaveta Malashenko, CPUC’s deputy executive director for safety policy, said in a review of last week’s event. “And they are currently sources of failure for PG&E.”
PG&E covers a far larger and more challenging territory to protect in a similar way, but it’s under CPUC order to get there as quickly as possible. It has installed hundreds of weather stations and fire-spotting cameras across its territory, and has plans to deploy thousands more in the coming year, with real-time data available at its web site, he said.
But it’s also struggling to keep up. PG&E reported last month that it has only completed clearing tree limbs, brush and other vegetation from about one-third of the 2,455 miles of power lines it had promised under its Enhanced Vegetation Management program. On Friday, Singh updated that to about 1,000 miles of line cleared of vegetation, as well as covered about 100 miles of bare wires with plastic shielding to deflect falling tree limbs, out of 150 miles called for in its plan.
PG&E’s poor safety record, and incentive to err on the side of caution to prevent its equipment from starting another massive wildfire to add to its financial liabilities, have soured California’s political leaders and general public alike on its ability to meet the demands for improvement laid out by Gov. Gavin Newsom and the CPUC last week.
But as CPUC President Marybel Batjer noted in Friday’s meeting, “We are at a historic peak of the wildfire season and time is of the essence.” And according to Monday news reports, the next test of PG&E’s capabilities could come later this week, as high winds and dry conditions prompt fire risk warnings across the state.
Source: Greentech Media
