“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.