California’s largest natural gas storage facility, Aliso Canyon, was cleared to reopen at limited capacity late Wednesday following months of rigorous inspections and well analysis by state engineering and safety enforcement experts.
Opening the facility would “protect public safety and prevent an energy shortage in Southern California,” officials said.
Under state Senate Bill 380, the Division of Oil, Gas and Geothermal Resources (DOGGR) and the California Public Utilities Commission (CPUC) had to agree that the facility was safe before any gas injection could resume. No timeline was provided as to when injections may restart.
“In order to protect public safety and the environment, this facility will be held to the most rigorous monitoring, inspection and safety requirements in the nation and will store only the minimum gas necessary to supply the Los Angeles area,” said DOGGR State Oil and Gas Supervisor Ken Harris. “The extensive testing, retrofits and new safety measures ensure the wells are in sound operating condition today.”
The testing process was developed in close coordination with experts from Lawrence Berkeley, Lawrence Livermore and Sandia National Labs. Southern California Gas Co. (SoCalGas), which owns and operates the facility, requested permission to resume natural gas injections last November.
“After careful review of testing results, our safety teams have confirmed the integrity of the wells at this facility,” said CPUC Executive Director Timothy Sullivan. “Out of an abundance of caution and consideration for public safety, storage capacity will be restricted to approximately 28% of the facility’s maximum capacity -- just enough to avoid energy disruptions in the Los Angeles area.”
Earlier this month state officials said the root cause of the leak still was unclear.
DOGGR suspended natural gas injections at the facility after a major leak was discovered in October 2015. The leak was permanently sealed four months later. DOGGR also ordered a comprehensive safety review in which each of the 114 wells in the facility either had to pass a battery of tests to potentially be eligible to resume gas injection or be taken out of operation and isolated from the reservoir.
The testing protocol, approved by independent national laboratories, included:
Lowering sensors into the well to measure temperature and verify the integrity of the well;
Lowering an acoustic sensor to confirm no gas was leaking;
Extensive measurements of the well casing walls;
Sonic test to confirm adherence between cement and the external casing of the well;
Multi-arm caliper inspection to verify the casing’s ability to withstand pressure; and
Pressure test to confirm the well remained sound when the pressure is 115% its maximum operating pressure.
In addition to the testing protocols, about 60% of the wells have now been taken out of operation and isolated from the facility. All the remaining wells that passed the stringent battery of tests were subject to stringent retrofit and inspection requirements.
Under the emergency rules passed last year, active wells are now equipped with real-time pressure monitors, and SoCalGas is required to conduct routine aerial monitoring for the presence of any methane. In addition, Wellheads are to be inspected daily using infrared and other leak-detecting technology. All wells used for injection and production also have new steel tubing and new seals (known as packers) inside the wellbore.
Under the new requirements, the gas pressure in the storage reservoir has been reduced, from 3,600 psi to 2,926 psi. Also, another layer of protection ensures that gas flows only through an inner steel pipe to allow the outer casing to serve as a secondary safety barrier.
“While these aggressive new safety protocols take effect, the independent investigation into the cause of the Aliso Canyon leak continues,” state officials said. “SoCalGas has prepared a risk management plan that identifies prevention and mitigation steps for potential hazards, and a supplemental analysis of the seismic risk to the facility is in process.”
Additionally, the CPUC “continues to a hold a proceeding that will decide the future of the facility.”
Following the report, California Energy Commission (CEC) Chair Robert B. Weisenmiller in a letter to CPUC President Michael Picker urged the commission to plan for Aliso’s closure within a decade.
“The recent gas leak at the Aliso Canyon natural gas storage facility reminds us of the dangers of our dependency on fossil fuels,” Weisenmiller said. “The actions we take regarding our energy infrastructure now will shape our ability to realize the state’s fight against climate change over the next decade, if not the next century.”
Under Gov. Jerry Brown, he said, California “has set some of the most ambitious climate change goals in the world...In order to meet this goal, we must take decisive actions now to increase the use of renewable energy, improve energy efficiency, electrify the transportation sector and expand the availability of cleaner fuels and technologies.
“With the state’s climate target in mind, Gov. Brown has asked me to plan for the permanent closure of the Aliso Canyon natural gas storage facility, and I urge the CPUC to do the same.”
Under SB 350, CPUC is directed to consult with the CEC considering Aliso’s future, he noted.
“My staff is prepared to work with the CPUC and other agencies on a plan to phase out the use of the Aliso Canyon natural gas storage facility within 10 years,” Weisenmiller said.
“Closure of Aliso Canyon is no small task and the recommendation to close the facility is not one that I take lightly or without thoughtful consideration. However, I am confident that through sustained investments in renewable energy, energy efficiency, electric storage technologies and other strategies, we can make this transition a reality.”
Over the short term, he said state officials needed to monitor Southern California’s energy reliability through peak usage in the summer and winter, as well as pursue “effective mitigation measures to meet the energy demands of residential and commercial customers.”
The governor’s 2016 emergency proclamation on the Aliso Canyon leak called for an assessment of the long-term viability of all natural gas storage facilities in California, the CEC chair noted.
“This assessment is well underway and is being conducted by an independent team of scientists organized by the California Council on Science and Technology. It is scheduled to be complete at the end of the calendar year and will inform how the state will rethink all natural gas storage facilities in California.”
Said Los Angeles City Councilman Mitchell Englander, “While I am disappointed in the state's decision to resume operations at the Aliso Canyon Natural Gas Storage facility, I am encouraged that the CEC will proceed with a plan to permanently close the facility within 10 years.
“The gas leak of 2015-16 was the largest in our nation's history and showed the danger of operating such facilities near residential areas. And while state regulatory agencies have taken steps to improve safety at the facility, the only way to ensure that history does not repeat itself is through permanent closure of the facility.”
Aliso permitting and oversight is not under the jurisdiction of Los Angeles officials, Englander noted.
“Nevertheless, I will continue to work with the relevant county, state and federal agencies to expedite the day when the Aliso Canyon facility can be brought offline."