SAN DIEGO (AP) — Federal regulators have told six utilities and grid operators that they violated reliability standards during a 2011 blackout that left millions without power in Southern California and Mexico.
The preliminary findings by Federal Energy Regulatory Commission staff could lead to penalties or requirements to upgrade systems. One public utility, the Imperial Irrigation District in Southern California, said it was in settlement talks that would result in $9 million for upgrades and $3 million in penalties.
A failed maintenance procedure at an Arizona Public Service transmission switch yard near Yuma, Ariz., led to the blackout on the afternoon of Sept. 8, 2011, knocking out power to 2.7 million homes and businesses in Arizona, Southern California and Tijuana, Mexico, on a hot summer day. The entire San Diego area lost power — some customers for up to 12 hours — forcing schools and businesses to close and creating horrendous traffic jams as drivers navigated without traffic signals or street lights.
FERC said in April 2012 that the grid quickly became overloaded when power was rerouted from Yuma, a loss that it should have been able to sustain.
The California Independent System Operator, which operates the state power grid, says it doesn't believe it violated any reliability standards. It said it is "continuing to cooperate with FERC in its investigation and will evaluate its next steps as the matter proceeds."
Others cited by FERC staff on Jan. 22 are Arizona Public Service Co.; Southern California Edison; the Western Electricity Coordinating Council; and the Western Area Power Administration.
Southern California Edison, which shut the San Onofre nuclear power station during the blackout, said its system operated as it should have. San Onofre has since closed over unrelated safety issues.
"(Edison) fully believes immediate actions taken by the utility helped to mitigate a larger electric grid emergency that could have had a significantly more detrimental and longer-term impact on Southern California regional electric customers," Southern California Edison, a unit of Edison International, said in a statement.
Arizona Public Service, which serves more than 1.1 homes and businesses in Arizona, said the FERC notice was "an interim step in the resolution of this matter" and that it has taken measures to avoid another mass blackout.
The Western Electricity Coordinating Council, an industry group that oversees power deliveries in the western U.S., "is moving forward to bring this matter to a close," spokeswoman Heather Rasmussen said.
The Western Area Power Administration, a part of the U.S. Department of Energy that markets power, declined to comment because the investigation is not yet finished, spokesman Randy Wilkerson said.