Officials with the California ISO have provided more details on the steps they took during power shortages starting Aug. 14 that led to rolling blackouts.

CAISO suspended convergence bidding, which is due to be reinstated Aug. 22, and utilized exceptional dispatch and its capacity procurement mechanism to secure backstop generation. It also curtailed exports as the grid operator scraped up every megawatt it could, along with suspending the $1,000/MWh cap on energy bids.

CAISO officials on an Aug. 21 conference call noted that the heat wave is expected to continue, and thanked other agencies and utilities for pulling together and conserving electricity, helping to avoid further outages.

"It really does take a village to get through a heat wave," Guillermo Bautista Alderete, CAISO's director of market analysis and forecasting, said on the call.

Outgoing CAISO CEO Steve Berberich on Aug. 17 put the blame on the state's resource-adequacy program regulated by the California PUC, saying the ISO had pointed out issues with capacity procurement "over and over again."

"I think it is important to understand the ISO operates the system it is given," Berberich said. He said CAISO should have pointed out the possibility of outages sooner, but was caught by a 500-MW generation unit tripping off line at about 3 p.m. and the loss of wind generation between 4:10 p.m. and 5:10 p.m. on Aug. 14.

CPUC spokeswoman Terrie Prosper in a statement said that securing adequate electricity supply is "a shared responsibility," and that the CPUC is working with other agencies "to better understand why this occurred."

"The electricity demand of the last few days is consistent with the level the agencies have for August, and the utilities and community choice aggregators procured the resources that were required to meet the forecasts," Prosper added. "The question we're tackling is why certain resources were not available."

Gov. Gavin Newsom declared a state of emergency Aug. 17 because of extreme heat and said he had called an all-hands meeting with regulators and grid operators. In a news conference, he said the state might be about 4,400 MW short of power that day, in part due to the extended heat wave in California and milder-than-usual wind. CAISO backed up that number at the meeting. The grid operator ended up calling a Stage 2 emergency Aug. 17, but did not have to shed load because energy users cut their consumption and temperatures fell.

State officials are reacting in a number of different ways to the blackouts, and are considering the following mitigation strategies, among others: reducing consumption at shipping ports, which utilize "tremendous amounts of energy," Newsom said; reducing consumption by the state's largest commercial buildings; reducing electricity exports; and better understanding the interrelationship between CAISO, the CPUC and the California Energy Commission.

"We failed to predict and plan [for] these shortages," Newsom said. "As governor, I am ultimately responsible . . . We cannot sacrifice reliability."

State officials are deploying every resource they can, and hope to ensure the rolling blackouts "simply never happen again in the state of California," according to Newsom.

Pacific Gas & Electric spokesman Jeff Smith said on Aug. 17 that the utility called two different outages at about 6:40 p.m. Friday, Aug. 14 and 6:10 p.m. Saturday, Aug. 15 that affected between 220,000 and 250,000 customers.

In a Stage 3 emergency, utilities are directed to cut power by CAISO, unlike in public safety power shut-offs, which are called by utilities. Smith said PG&E was not able to prepare customers prior to the called blackouts over the weekend. "With 10 minutes' notice, it's difficult to notify customers, especially because of the unique nature of this," he said.

Two different outages were also called for San Diego Gas & Electric customers on Aug. 14. One of about 60 MW affected 28,000 customers for about an hour, and another 80-MW cut affected about 31,000 customers for 21 minutes. About 38 MW was cut on Aug. 15, affecting about 17,000 customers for 20 minutes.

"All impacted customers had their power restored as of 8:03 p.m.—about an hour and 20 minutes after the rotating outages began," SDG&E spokeswoman Jessica Packard said.

Alameda Municipal Power had a trifecta of woes, not all of which were rolling-blackout-related, according to spokeswoman Rebecca Irwin. The utility's blackouts involved 5 MW of power and roughly 3,500 customers between about 6:45 p.m. and 7:50 p.m. Aug. 14. Irwin said this was abbreviated compared with what the muni had initially prepared for: "What we thought was going to be bigger didn't happen." Expected outages on Aug. 15 "got pulled at the last minute," she said.

"To complete our lovely weekend, the lightning storm we had on Sunday hit one of our substations and hit a utility pole and took out three transformers," Irwin said. The Aug. 16 storm-related outages affected 10,000 people, but power was restored within two hours.

Irwin said the utility was "watching everything and waiting to see" if another series of blackouts is called, "sitting in a holding pattern" and "putting out the message: conserve, conserve, conserve."

Anaheim Public Utilities instituted four different 15-minute outages involving 10.3 MW Aug. 14, according to city spokeswoman Erin Ryan. Roughly 10,000 customers were briefly without power between 7 p.m. and 8 p.m. Ryan said the utility sought to spread the outages across a greater number of customers for an abbreviated time rather than make a small number of customers swelter in the excessive heat for an hour. Should other rolling blackouts be called, she said, the city would also execute these in 15-minute increments.

Utilities within the Balancing Authority of Northern California—Sacramento Municipal Utility District, Modesto Irrigation District, Roseville Electric, City of Shasta Lake, Trinity Public Utilities District and Redding Electric Utility—were not subject to CAISO's call for rolling blackouts, as BANC operates independently from CAISO. "By controlling its own system, BANC is not required to participate in rotating outages that might be required of California utilities, which are located in other balancing authority areas," BANC said in an Aug. 16 news release.

SMUD had no outages as of the afternoon of Aug. 17, according to utility spokesperson Chris Capra. "The only outages have been from heat-related stress on the system," he said. Those were repaired quickly. The largest, which occurred Aug. 16, affected 700 customers. Like most utilities across the region, SMUD has been making direct appeals to customers to conserve energy between 1 p.m. and 9 p.m. daily.

In an Aug. 17 letter to the CEC, CPUC and CAISO, Newsom called for the CEC to review its forecasts, CAISO to review its assumptions regarding solar power and other resources, and the CPUC to review its resource-adequacy requirements.

"Collectively, energy regulators failed to anticipate this event and to take necessary actions to ensure reliable power to Californians. This cannot stand," Newsom said in the letter. "The failure to predict these shortages is unacceptable, particularly given our state's work to combat climate change."

California received some help from the Northwest during the power emergencies. BPA provided as much generation to California "as we could within our power and transmission capabilities, including emergency power to CAISO on occasion," Bonneville spokesman David Wilson told Clearing Up in an email. "Between August 14 and 19, BPA sold nearly 65,000 MWh of hydropower" from the Federal Columbia River Power System to CAISO and California load-serving entities at the California-Oregon border and Nevada-Oregon border interties.

According to BPA generation and load data, its peak hydropower levels ramped up by 50 percent and its load by 25 percent in the days leading up to the California grid problems.

News Editor - Clearing Up

Rick Adair has been with NewsData since 2003, and is news editor for Clearing Up and editor for Water Power West. Previously, he covered environmental and energy issues in the Lake Tahoe area. He has a doctorate in earth sciences.

Staff Writer

David Krause is an energy reporter covering the California Energy Commission and Air Resources Board. He writes about transportation, climate change, utilities, and wildfires. He has an MFA in Writing, an MA in English, and a BS in Civil Engineering.