California regulators on Monday ordered Southern California Gas Co. (SoCalGas) to increase the range of working gas volumes to 34 Bcf at the Aliso Canyon underground natural gas storage facility in Southern California, the state's largest.
The California Public Utilities Commission (CPUC) energy division published its summer supplemental report and cited the current "unprecedented level of outages" on the SoCalGas pipeline system as contributing to the need to increase Aliso volumes, which have been restricted for the past three years since the massive storage well leak that lasted four months in 2015-2016.
In the report and a subsequent letter from Executive Director Alice Stebbins, there is reference to the need to increase the maximum allowable Aliso inventory to 34 Bcf from 24.6 Bcf "to maintain safe and reliable service."
The latest report by the CPUC energy division focuses on whether SoCalGas can meet all system demand on a 1-in-10-year peak day.
"The report's time frame was updated to look beyond summer 2018 to winter 2018-19 due to the outages on the SoCalGas pipeline system," Stebbins said in her letter to SoCalGas's Rodger Schwecke, senior vice president for gas transmission and storage.
Stebbins emphasized that the latest report included consultation with the California Energy Commission, California Independent System Operator and Los Angeles Department of Water and Power (LADWP).
In a letter late last month to the CPUC, SoCalGas expressed support for the larger maximum allowable inventory at Aliso because its helps system reliability, and it recommended that the storage field's withdrawal protocol be modified to eliminate the need for voluntary generator curtailment before withdrawals can take place.
"This modification will allow Aliso Canyon to better support system reliability," the Sempra Energy gas-only utility said.
The context for the CPUC’s latest move at Aliso comes as concerns about the pipeline outages have grown.
California has finalized regulations for underground natural gas storage aimed at public health and safety nearly three years after the methane leak at Aliso Canyon. The regulations, which are set to take effect Oct. 1, would replace emergency rules that took effect in early 2016.
SoCalGas has been asked to provide to CPUC additional information on the pipelines as regulators consider an investigation and assess utility rate adjustments for the prolonged down time for the transmission lines. The major focus is on Line 3000, which has been down since July 2016, and Line 235-2, which ruptured last October.
The CPUC noted that under one set of scenarios, an additional 180 MMcf/d of pipeline capacity is expected to be lost in September based on this summer's technical assessment by the Aliso Canyon Technical Assessment Group, which includes several state agencies and the LADWP.
CPUC staff emphasized that the latest report provides an analysis of "what is required to manage Southern California's gas reliability over the short term.” The ultimate decision of whether Aliso will be used over the long-term is the subject of a separate, ongoing CPUC proceeding.