After a long stretch of summer with below-normal temperatures across most of the state, California is embroiled in its first sustained heat wave, sending electric grid peaks to highs for the year and putting a strain on the utilities and grid operator, which are operating without the full use of the natural gas storage facility at Aliso Canyon in Southern California, the hottest of the hot spots.
The California Independent System Operator (CAISO) on Tuesday issued a conservation alert which is expected to be repeated all week, given forecasts for triple-digit temperatures for the inland valleys and desert regions, and high-90-degree temperatures in areas that include downtown Los Angeles.
After topping 47,000 MW for peak loads Monday and Tuesday, CAISO forecast a peak of slightly more than 46,000 MW on Wednesday and 47,715 MW Thursday. The heat wave is expected to hit its highest temperatures on Friday, when even coastal areas and San Francisco could see temperatures near 90 degrees.
"Consumers are urged to conserve electricity especially during the late afternoon when air conditioners typically are at peak use," a CAISO spokesperson said. In homes, the use of major appliances is suggested to be restricted to before 2 p.m. and after 9 p.m. during the "Flex Alert" days.
Pacific Gas and Electric Co. and other utilities echoed the grid operator's warning with public service announcements to customers.
No statistics were available about the amount of natural gas-fired generation being applied, but gas generators usually provide more than half (53%) of CAISO's available generation capacity, with renewables at 29% and large hydroelectric chipping in 12%.
A Southern California Gas Co. (SoCalGas) spokesperson told NGI on Wednesday that no supplies so far had been withdrawn from the partially curtailed Aliso Canyon underground gas storage facility, the state's largest.
SoCalGas resumed natural gas injection operations at Aliso Canyon on July 31, with utility officials indicating that summer heat and pipeline maintenance projects could necessitate withdrawals. State regulators have cleared Aliso's reopening at limited capacity following months of rigorous inspections and storage well analysis by state engineering and safety enforcement experts.
The Environmental Defense Fund (EDF) said in blog post Wednesday that PG&E and SoCalGas have made progress curtailing methane emissions from their utility gas systems since a state Senate Bill 1371 was enacted in 2014. Setting aside the estimated 6.2 Bcf of gas lost in the recent Aliso Canyon leak, SoCalGas leaks have declined by 3% and PG&E by 11% over the past two years.