- About 115,000 customers on San Diego Gas & Electric's system lost power on Sept. 20 when the utility shed 150 MW of load in response to directives from the state's grid operator.
- The California ISO told the utility that it feared more widespread outages if SDG&E didn’t immediately reduce energy deliveries.
- According to Fox 5 San Diego, CAISO is investigating the outage because it appears the grid had available power during the event.
It's not entirely clear what happened in California over the weekend. About 115,000 customers lost power for two hours, and San Diego Gas & Electric says it's because the state's grid operator directed it to shed load.
"As a result, SDG&E had to immediately initiate short power outages," the utility said in a statement. "The CAISO indicated that there was a concern of more widespread outages, if SDG&E didn’t immediately comply with the request to reduce energy deliveries to our customers."
The utility went on to say that "reliability is a priority," but added that "if measures were not taken to preserve the balance of the generation available and the high demand of customers, the result could have been additional power outages."
But according to Fox 5 San Diego, the CAISO web site had indicated that it had 48,000 MW of power available on Sunday afternoon. And when the news outlet called CAISO, the grid operator said they were aware of SDG&E's statement and were investigating.
Though the statement did not specify the amount, on Twitter SDG&E said the grid operator had directed it to shed 150 MW.