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What Caused August's Rolling Blackouts? Experts Say It's Still Not Totally Clear

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Los Angeles' downtown skyline in August during the state's first major rolling power outage since 2001. (Photo by Apu Gomes/AFP via Getty Images)

In their ongoing investigation into what caused California's rolling blackouts in August, the state’s electrical grid operator and utility regulators have focused primarily on structural issues like climate change-driven heat and the transition to renewable energy sources.

But two months after the historic event, officials still haven’t come up with a definitive set of answers.

“We’re still trying to do a lot of work to understand the data we have,” Delphine Hou, director of regulatory affairs for the California Independent System Operator (CAISO), said during a public stakeholder's call last week.

The rolling blackouts, the state's first in almost two decades, thrust more than 800,000 Californians into the dark during an intense heatwave on Aug. 14 and 15, when operators directed utilities to shut down power to prevent the grid from being overwhelmed. But some energy experts say key questions about the sequence of events that led to the blackouts have gone unanswered or unacknowledged.

For example, CAISO’s public summaries — including a 108-page Oct. 6 preliminary analysis compiled jointly with the state's Public Utilities Commission and Energy Commission — makes no mention of an outage that occurred at Ormond Beach Unit 1 in Oxnard, a natural gas plant with a whopping 741-megawatt generating capacity. The plant went offline for maintenance just eight minutes before CAISO declared a Stage 3 emergency on Aug. 14, notes energy expert Bill Powers, the head of Powers Engineering in San Diego. He says the record of that incident is buried in a spreadsheet.

Instead, CAISO’s timeline focuses on a plant in Blythe, a city in Riverside County, where an outage that same afternoon had been resolved for more than 40 minutes by the time CAISO called for rolling blackouts.

“The ISO's messaging in the immediate wake of these blackouts was nontransparent and much of it appears to be incorrect,” Powers said. “Ormond Beach is the elephant in the room. Why is that elephant invisible? Why are we talking about Blythe Energy Center which had nothing to do with the blackout?”

There are also lingering questions about CAISO’s accounting of events on Aug. 15, when the liaison between CAISO and Panoche Energy Center, a power plant near Fresno, issued what CAISO calls an “erroneous dispatch.”

That liaison, known as a scheduling coordinator, told the power plant to ramp down output as demand was peaking. A CAISO outage report issued on Sept. 11 omits that PG&E was the scheduling coordinator, and that its personnel made the erroneous dispatch.

The San Francisco Chronicle and KQED reported last month on PG&E’s role, which is also left out of the Oct. 6 analysis.

PG&E’s action — which resulted in 248 megawatts of power coming off the state’s grid — took place three minutes before CAISO declared a Stage 2 emergency, denoting it was no longer able to provide expected energy requirements. The Stage 3 declaration — signaling that shutoffs were imminent — followed 12 minutes later.

PG&E says the ramp-down lasted less than half an hour, and that it corrected the error immediately upon identifying it.

“PG&E does not know if the error resulted in rotating outages,” said company spokesman James Noonan.


The utility did not respond to KQED’s questions about whether it took action to prevent similar incidents from happening again, or if any company personnel were disciplined.

“People make mistakes. That's why well-run organizations have checks and balances to discover those mistakes before they cause harm,” said Steve Weissman, a lecturer at the UC Berkeley Goldman School of Public Policy.

“In the past, PG&E has run into problems because it has not tended to maintain those kinds of quality control processes,” he said. “If PG&E had systems in place to catch those mistakes, why did they miss this one?”

For the last several weeks, CAISO has declined KQED’s requests to review recordings of verbal communications between PG&E and CAISO, which could shed light on whether CAISO was aware of the error in real time.

In a statement, PG&E said the utility informed CAISO of the full details of the incident three days later.

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The issue of how quickly CAISO can see — and react to — what the state’s many power resources are producing, matters significantly as California transitions away from fossil fuels to more renewable energy sources, according to Daniel Kammen, director of UC Berkeley's Renewable and Appropriate Energy Laboratory (RAEL).

“We need a system with better data feedback and more real-time updates so CAISO can make the right decisions,” Kammen said. “We need to know precisely what’s happening. Technology makes that very possible today.”

While Kammen hasn’t studied what happened at the Ormond Beach plant, he says the timing of the rolling blackouts looks “completely tied” to that lack of capacity. In his view, energy storage is critical to ensuring reliability during the growing shift to renewables.

“They simply don’t know what resources they have available to them. We’ve had 10 years of planning to try and fix that,” Kammen added. “That’s CAISO’s job. If they don’t have the capacity, they should ask the governor’s office and the [public utilities commission] for whatever they need to get there.”

CAISO officials have highlighted problems with the complex energy market it operates. In that market, much of the state's power is booked just a day in advance. A practice called “convergence bidding” — which involves trading virtual power — is intended to smooth the gap between the day-ahead and real-time markets.

“We were not set up correctly,” Hou said on last week’s call. “So the real-time market had to work extra hard to untangle what was set up a day ahead.”

According to the Oct. 6 analysis of the blackouts, scheduling coordinators “under-scheduled” or didn't line up enough power ahead of time, meaning the market didn't “reflect the actual need on the system.” That, in turn, signaled that “more [energy] exports were ultimately supportable.”

In other words, says former CPUC President Loretta Lynch, California was exporting power up until CAISO called for rolling blackouts. “They were serving the energy traders over the California economy,” Lynch said.

CAISO contends that the regionwide August heat storm made import opportunities scarce. On last week’s call, when asked why it did not consider curtailing exports during the two-day blackout, an official asked for patience.

“We need to put into perspective how the timing of this happened. We started taking action as we unraveled these layers,” said Guillermo Bautista Alderete, CAISO's director of market analysis and forecasting. “We have to first analyze what happened. Then understand what happened. Then look at our next opportunity to effectuate change.”

In the last week, CAISO has announced the departures of two top executives: Vice President of Operations Eric Schmitt and Vice President of Technology Petar Ristanovic. A CAISO spokesperson said both men had been considering retirement for some time, and that their decisions were unrelated to this summer’s outages.

In the coming weeks, experts will be looking for signs of a paradigm shift in how the state ensures it can provide reliable power to Californians.

“How do we keep the lights on in a world in which a growing share of generation capacity supplies power when the sun is shining and the wind is blowing?” asked Frank Wolak, an economics professor at Stanford, who chaired CAISO's Market Surveillance Committee from 1998-2011.


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