No major infrastructure damage was sustained by San Diego-based Sempra Energy’s natural gas and electric utility infrastructures in the area, nor to its independent natural gas pipeline and liquefied natural gas (LNG) receiving terminal in North Baja California.

Electric grid operations were back to normal in California Tuesday after the major earthquake that hit last Sunday in a mostly sparsely populated patch of northeast Baja California, south of Mexicali and Calexico, towns on the Mexico and California sides of the international border, respectively. A California Independent System Operator (CAISO) spokesperson confirmed that the Southwest Power Link was back in operation.

Sempra Energy’s two California utilities, Southern California Gas Co. and San Diego Gas and Electric Co. (SDG&E), responded to impacts on the natural gas distribution system and the electric transmission grid in the area in the southeast corner of California where the Imperial Valley flows into parts of North Baja California. Sempra’s independent power generator, Sempra Generation, also was busy working to restore operations at its Termoelectrica de Mexicali, a $350 million, 625 MW generating plant in Mexicali, Mexico.

The merchant power plant, which feeds supplies into the CAISO grid, stayed offline Tuesday as more assessments were being made to determine if it sustained any damage from the quake, a spokesperson for Sempra Generation told NGI. The company expects to have a clearer idea of when the plant could be restarted some time on Wednesday.

SDG&E’s Imperial Valley Substation was damaged by the 7.2 magnitude earthquake that hit Easter Sunday around mid-afternoon, and subsequently the Southwest link, a high-voltage major 530 kV transmission line was knocked out of service for a while, according to the CAISO spokesperson. There were no transmission-related outages, however, he said, noting that operations were back to normal Tuesday, although utility repairs may go on longer. (A call into SDG&E was not immediately returned Tuesday.)

In San Diego a Sempra Energy corporate spokesperson confirmed that the company’s 1 Bcf/d LNG receiving terminal on the Pacific Coast of North Baja California, about 60 miles south of the international border, was unaffected by the quake, for which there were hundreds of aftershocks continuing. Similarly, the Sempra North Baja natural gas transmission pipeline was not impacted along its Mexican route traversing the north end of Baja.

Separately, CAISO said a 45-minute outage in San Diego last Thursday, shortly after midnight, under initial scrutiny appears to be the fault of personnel in the grid operator’s control room. “Preliminary findings indicate that CAISO improperly allowed a San Diego area power plant to shut down,” said a statement from the grid operator released Tuesday.

Control room personnel involved in the event have been reassigned off the control room floor pending completion of the grid operator’s internal review, CAISO said.

“We acted in good faith, but we made mistakes, first allowing this situation to occur by not maintaining adequate local generation in San Diego,” said CAISO’s Jim Detmers, vice president for operations. “This was unacceptable and I am sorry it happened, and I apologize to the people of San Diego who were impacted.”

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