The three California organizations that oversee electricity responded to a request by Gov. Gavin Newsom to explain why the state had two days of rolling blackouts on Aug. 14 and 15 and would have had more if not for statewide conservation efforts.

“We agree that the power outages experienced by Californians this week are unacceptable and unbefitting of our state and the people we serve,” CAISO, the Public Utilities Commission and the Energy Commission told Newsom in a joint letter last week. “We understand the critical importance of providing reliable energy to Californians at all times, but especially now, as the state faces a prolonged heat wave and continues to deal with impacts from the COVID-19 pandemic.”

The organizations operate independently but coordinate efforts to supply the state with electricity. CAISO operates the transmission grid. The CPUC regulates investor-owned utilities and orders procurement. The CEC forecasts demand, among other functions.

“We are working closely as joint energy organizations to understand exactly why these events occurred,” they said.

The tone of shared responsibility differed from CAISO initially blaming the CPUC for failing to procure sufficient energy despite warnings of capacity shortfalls starting this summer. (See CAISO Blames Blackouts on Inadequate Resources, CPUC.)

Leaders of the three organizations said their staffs would need more time to fully analyze the causes of the blackouts, but they provided Newsom with their initial findings. The letter was signed by CAISO CEO Steve Berberich, CPUC President Marybel Batjer and CEC Chair David Hochschild.

Demand on Aug. 14-15 was high, peaking at approximately 47 GW and 45 GW respectively, they said, “but not above similar hot days in prior years. Given this, our organizations will need to conduct a deep dive into how we ensure sufficient electric supply and will make modifications to our reliability rules to make sure reliability resources can be available to address unexpected grid conditions.” (See CAISO: Blackouts May Continue, Calls Emergency Meetings.)

The state’s “heavy reliance” on imports was one obvious factor in the blackouts, the leaders told Newsom.

The heat wave that engulfed the West in triple-digit temperatures dried up imports that weren’t secured by long-term contracts, CAISO said. It struggled to meet peak demand during the late afternoon and evening hours and would have ordered additional days of rolling blackouts if conservation efforts hadn’t cut demand by 2,000 to 3,000 MW and the state hadn’t secured more megawatts. (See ‘Last Challenging Night’ for CAISO, Governor Hopes.)

Conservation, More MWs

The organizations provided additional details on those efforts in the letter to Newsom.

The CEC coordinated with data centers in Silicon Valley to move approximately 100 MW of load to on-site backup generation, the letter said. It worked with the U.S. Navy and Marine Corps to “disconnect 22 ships from shore power, move a submarine base to backup generators and activate several microgrid facilities resulting in approximately 23.5 MW of load reduction.”

The state Department of Water Resources and the Metropolitan Water District of Southern California shifted 80 MW of hydroelectric generation to peak demand times. The department and the U.S. Bureau of Reclamation made changes in pumping schedules that secured another 72 MW. And San Francisco maximized output at its Hetch Hetchy hydroelectric facilities to generate an additional 150 MW during peak demand periods.

CAISO and the CPUC have both warned of more severe shortfalls going forward as fossil fuel plants and the state’s last nuclear power generating station retire. The state’s switch to solar and wind resources isn’t to blame for the shortfall, but far greater storage is needed to meet “net-peak” demand after the sun sets, CAISO and the CPUC said recently. (See CAISO, CPUC Warn of ‘Reliability Emergency’.)

To avoid shortfalls in the coming summers, “forecasts and planning reserves need to better account for the fact that climate change will mean more heat storms and more volatile imports, and that our changing electricity system may need larger reserves,” the organizations wrote.

The CEC is holding sessions Wednesday to help forecast demand through 2030, with the recent shortfalls part of that discussion.