A U.S. Department of Energy (DOE) official pressed last week for California regulators to reopen the Aliso Canyon natural gas storage facility while opponents on Monday continued to push for the 3,600-acre facility to be permanently closed.

In a letter to the California Energy Commission (CEC), DOE’s Patricia Hoffman, undersecretary for science and energy, supported Aliso Canyon as important for the region to avoiding future energy supply disruptions. Even with the state’s ongoing winter/summer mitigation plans and the return of an above-normal hydroelectric power season, the region is at risk without Aliso or “an adequate functional equivalent,” she said.

“The reality is that there are many constraints to the transmission of electricity and natural gas in California that are only exacerbated by Aliso Canyon being unavailable in its full capacity,” she said.

CEC Chairman Robert Weisenmiller said the state’s mitigation measures have been working but “prolonged periods of hot weather and other unpredictable events” can create problems for the region’s electricity delivery.

Criticism of the facility arose again this week during a Joint Agency Task Force meeting of the CEC, California Public Utilities Commission (CPUC), California Independent System Operator and the Los Angeles Department of Water and Power. Opponent allege mismanagement by the facility owner/operator Southern California Gas Co. (SoCalGas) to win state approval to reopen the shuttered facility.

The “Aliso Canyon Risk Assessment Technical Report Summer 2017 Assessment” issued last week supports the contention that the 86 Bcf-capacity facility, the largest in California, is not needed to assure adequate power supplies this summer, a representative for the Food & Water Watch (FWW) environmental group said.

State regulators have said the best way to guarantee a reliable supply of gas without Aliso Canyon is to use daily gas balancing, but they have not required SoCalGas to do so, according to FWW senior organizer Alexandra Nagy.

“In an attempt to build its case to reopen the dangerous Aliso facility, SoCalGas is mismanaging the gas system to create a shortage designed to force the reopening of the gas facility,” Nagy said. California Gov. Jerry Brown and the CPUC “must stop this mismanagement now and require SoCalGas to implement daily energy balancing to ensure energy reliability and close the leaky Aliso Canyon for good.”

Residents and environmental groups during a press conference Monday called for Aliso to be shut down permanently. They labeled SoCalGas’ unbending defense of the storage facility as a “Blackout Blackmail Brigade,” including the groups supporting the Sempra Energy utility’s call to reopen the facility.

California regulators in January launched an 18- to 24-month investigation to determine whether to reduce or eliminate Aliso operations. Since thefour-month storage well leak in 2015 and early 2016, many residents, activists and elected officials have questioned its long-term future.

SoCalGas last winter justified withdrawals from Aliso Canyon to the CPUC, but Food & Water Watch, Consumer Watchdog and the elected Los Angeles County Board of Supervisors have called for an investigation.

According to Nagy, the state joint agencies are “continuing to allow the SoCalGas to mismanage the supply through the peak summer months.”

Authors of the latest summer assessment emphasized that this year’s work is based on a different analysis than was used in last year’s assessment. “The 2017 assessment calculates the system capacity of the SoCalGas/San Diego Gas & Electric gas transmission system, based on peak hour(s) supportable demand and determines the ability for the electric balancing authorities to maintain power system reliability during a 1-in-10 year peak summer electric load,” the assessment said.

This year’s assessment involves a power flow analysis reflecting full availability of all transmission pipelines in service and following a power system contingency.

“The objective of the power flow case was to minimize the use of gas-fired generation by fully utilizing the transmission import capability into Southern California,” the assessment said.