Fact Sheet: Ensuring Safe and Reliable Underground Natural Gas Storage

Department of Energy

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After providing Administration-wide support to the state response effort, in early 2016, the Obama Administration convened a new Interagency Task Force on Natural Gas Storage Safety in the wake of the nation’s largest ever natural gas storage leak at SoCalGas’s Aliso Canyon facility. This Task Force, which convened at the White House, was created as a part of the Administration’s ongoing commitment to support state and industry efforts to ensure the safe storage of natural gas. It is co-chaired by the Department of Energy (DOE) and the Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA), and is consistent with the task force requirements codified by Congress in the Protecting our Infrastructure of Pipelines and Enhancing Safety (PIPES) Act of 2016, signed into law by President Obama in June. The legislation created a task force established by the Secretary of Energy that consists of representatives from the Department of Transportation, the Environmental Protection Agency, the Federal Energy Regulatory Commission, the Department of Commerce, the Department of Health and Human Services, the Department of the Interior, and from state and local governments.  The PIPES Act tasked the group with performing an analysis of the Aliso Canyon event, making recommendations to reduce the potential for occurrence of similar incidents in the future, and required that PHMSA consider the findings and recommendations of this report as they work to develop minimum federal safety standards for underground gas storage to be issued within two years. 

The Task Force pursued three primary areas of study: integrity of wells at underground gas storage facilities, public health and environmental effects from a natural gas leak like the one at the Aliso Canyon underground gas storage facility, and energy reliability concerns in the case of future natural gas leaks. It held three public stakeholder workshops to hear from stakeholders and the public, and produced a report titled Ensuring Safe and Reliable Underground Natural Gas Storage. The report contains 44 specific recommendations. A summary of those recommendations is below:

Well Integrity

While the State of California is still analyzing the root cause of the Aliso Canyon leak, well records indicate that the leaking well was operated with a single point of failure design – allowing gas to flow through both production tubing and well casing, making the system dependent on a single barrier to contain the gas. The Task Force’s report found that if a second barrier had been in place, the uncontrolled leak could likely have been avoided. Additionally, the report notes that the inspection program, monitoring, and risk management plan for this well appear to have been inadequate to ensure safety. For example, well logs indicate that the majority of wells at the facility had not been recently evaluated for integrity.

Based on these findings and more, the report makes the following key recommendations addressing well integrity issues:

  • New wells should be designed so that a single point of failure cannot lead to leakage and uncontrolled flow, and except under limited circumstances, natural gas storage operators should phase out single point-of-failure wells.
  • Operators should adopt risk management plans that include a rigorous monitoring program, well integrity evaluation, leakage surveys, mechanical integrity tests and conservative assessment intervals.
  • DOE and DOT should conduct a specific and thorough joint study of subsurface safety valves.

Health and Environment

The report notes that, following the Aliso Canyon leak, residents of nearby neighborhoods experienced health symptoms consistent with exposures to odorants added to the natural gas, thousands of households were displaced, and approximately 90,000 metric tons of methane – a powerful greenhouse gas – was released from the well.

In order to prevent and mitigate similar health and environmental impacts in the event of future leaks, the report’s recommendations include:

  • In the event of a natural gas leak large enough to require multiple jurisdictions in the response effort, a “unified command” should be formed early so that leaders from each primary response agency can provide clear and consistent communications between agencies and with the public about progress toward controlling the leak and understanding the potential public health impacts of the release.
  • States and local monitoring agencies should consider establishing an emergency air monitoring plan that can be expeditiously deployed in the event of a leak.
  • States should review their authority to require greenhouse gas mitigation plans in the event of a leak.

Energy Reliability

The loss of the Aliso Canyon facility increased the likelihood of regional electric generation shortages in southern California this year. While communities were able to avoid electric curtailments this summer, maintaining electric reliability without Aliso Canyon remains a concern heading into winter. Other communities around the country could face similar concerns in the event of a leak in their region. Indeed, if such a leak led to a prolonged gas storage facility outage, the report finds that 12 of the nation’s underground gas storage facilities appear to have the potential to affect 2 gigawatts or more of available electric generation capacity.

The report makes the following key recommendations regarding reliability concerns:

  • Industry, Federal and state agencies should strengthen planning and coordination efforts to decrease the potential impacts of future prolonged disruptions of natural gas infrastructure
  • Industry, Federal and state agencies should consider broader application of back-up strategies to reduce reliability risks associated with the abrupt loss of natural gas supplies.

The full report is available here.

PHMSA plans to issue interim regulations regarding underground natural gas storage in the coming months, incorporating API Recommended Practices 1170 and 1171. The API RP would, for the first time, impose minimum requirements for operators to assess the operational safety of their storage facilities, and document the implementation of identified safety solutions. The Task Force’s report is intended to inform PHMSA’s phased rule-making process and to provide guidance to industry so that companies can begin implementing changes immediately.