Proposed federal rules governing the response of natural gas pipeline operators to ruptures on their systems could have unintended consequences if the rules do not allow the companies adequate flexibility, the gas industry warned.
In lodging their concerns, industry representatives sought to influence the final version of rules proposed in February by the U.S. Pipeline and Hazardous Materials Safety Administration, or PHMSA. The long-overdue rules would require gas pipeline operators to install remote-controlled or automatic shutoff valves on certain new or replacement pipelines and meet new standards for isolating transmission lines following a rupture.
The rulemaking would satisfy congressional mandates and National Transportation Safety Board recommendations driven by two 2010 pipeline disasters: the San Bruno, Calif., gas transmission line rupture in a neighborhood and Marshall, Mich., oil spill into a river. In both cases, investigators said the operators' failure to promptly shut off the supply to the lines exacerbated the catastrophes.
The valve rule addressed aspects of PG&E's response to the 2010 San Bruno, Calif., gas line explosion. It took the company 95 minutes to close mainline valves, allowing gas to feed the blaze.
Government, industry and civil society representatives on PHMSA's Gas Pipeline Advisory Committee, or GPAC, debated the technical feasibility, reasonableness, cost-effectiveness and practicability of the proposed rules during a remote July 22 meeting.
Regulating rupture response time
Several industry representatives argued against a proposed rule that would require pipeline operators to identify a rupture within 10 minutes of the initial indication. They said operators face the challenge of confirming information that arrives through several avenues. The 10-minute time limit would put pressure on companies to shut down a line even if they have not confirmed a rupture, potentially disrupting supply to manufacturers, residents and power plant operators without good reason, the industry representatives said.
Sudden demand spikes from large customers can produce changes in pressure typical of ruptures, particularly in the Northeast, according to Andrew Drake, vice president for asset integrity and technical services for gas transmission and midstream at Enbridge Inc. Control room operators may need more than 10 minutes to rule out a rupture after detecting a sudden pressure change, he said.
"I don't think you want me to say, 'Well, it's 10 minutes — close the valve, boys, and shut off New England on a cold day in the winter,'" Drake said. "You want me to go through that diligent process. It may take me 12 minutes or 13 minutes, but I think the key is a performance standard probably saves everyone a lot of headaches."
Richard Worsinger, director of North Carolina municipal utility Wilson Energy, said unnecessary pipeline shutdowns could cause significant difficulties for gas utilities by causing a loss of pressure that requires multiple visits to customer homes.
"That was a challenge before COVID-19 hit," Worsinger said. "Now with many systems having a prohibition of employees entering customers' homes [and] using contractors, or making sure we've got the right masks and [personal protective equipment], it's even more problematic."
GPAC members voted to eliminate the 10-minute threshold and to require companies to close valves within 30 minutes of identifying a rupture, down from 40 minutes in the proposed rule. The committee's decisions help to inform PHMSA final rules.
Balancing safety and environmental protection
Royce Brown of Enable Midstream Partners asked PHMSA to consider allowing pipeline operators to leave rupture mitigation valves open during certain rupture events, provided that emergency responders approve the action.
Brown, who is responsible for pipeline integrity, said gas utilities have implored his company to avoid service shutoffs because customers do not want workers entering their home during the coronavirus pandemic. Public safety is sometimes best served by venting gas through open valves in rural areas, rather than shutting down service, in order to observe social distancing or avoid disruptions during cold snaps, he said.
Mary Palkovich, vice president for gas engineering and supply at Consumers Energy Co., said allowing valves to vent following damage to distribution systems could help companies identify potential repair locations without disrupting service during the winter.
The final rule should reflect that venting methane, a potent greenhouse gas, is not ideal, said Sara Gosman, an assistant professor at the University of Arkansas School of Law. "I think it's important to point out that there are environmental consequences to continuing to release gas that we need to take into account here and balance against the safety set of issues," said Gosman, who sits on the board of directors of the Pipeline Safety Trust, which represents the public on the GPAC.
PHMSA staff resolved to consider allowing certain valves to remain open in select circumstances, with consideration paid to minimizing environmental damage.