Power industry officials said Wednesday they still don't have an answer for why the actions of one utility worker in Arizona triggered a cascade of outages that affected an estimated 7 million California residents—including all of San Diego County—on Sept. 8.
Their testimony came in a hearing conducted by the Assembly Committee on Utilities and Commerce and the Joint Committee on Emergency Response at San Diego City Hall.
Mark Maher, chief executive officer of the Salt Lake City-based Western Electrical Coordinating Council, said what happened that day was known, and the timeline was established.
"The outstanding question we have to pursue is why this happened,'' Maher said. "We know what failed and in what sequence, but we don't know why.''
Stephen Berberich, president and CEO of the California Independent System Operator, said the complex transmission system that carries power between various utilities should have absorbed the singular event of a worker in Arizona who switched lines out of sequence.
"This blackout should not have happened,'' Berberich said.
Instead, 20 separate events took place within 11 minutes to cause the widespread power outage, he said.
Among them, according to Berberich:
-- a power plant in northern Mexico stopped operating, but it is unknown whether that was in reaction to the Arizona event;
-- three power plants operated by the Imperial Irrigation District shut down in rapid succession;
-- the energy flow between Arizona and California was cut off; and
-- a transmission line south of San Onofre that connects San Diego Gas & Electric with Southern California Edison switched off, plunging San Diego County into a massive blackout.
The power industry officials said it could take anywhere from two months to one year to find out why the outage became as big as it did.
"Unfortunately, I feel a little less informed and a little confused,'' Assemblyman Ben Hueso, D-San Diego, said after their presentation.
The Western Electrical Coordinating Council assists various power system operators with the flow of electricity across 14 states, two provinces in Canada and part of Baja California Norte, according to Maher. Cal-ISO does the same within the state.
San Diego Gas & Electric President and CEO Michael Niggli credited customers for the return of power within 12 hours instead of two days, as originally estimated.
Niggli said unplugging air conditioners and other energy-hogging electronics allowed them to restart their system faster than expected.
-City News Service