How gas works: The science behind the heat

Nov. 10—When a landowner's plow ripped into an interstate natural gas pipeline near Pullman it also laid bare for what most Americans is an unseen and largely unknown infrastructure network.

The system that delivers the natural gas that heats our homes, powers our factories, and even fuels the grills and griddles of our favorite restaurants has vulnerabilities and carries threats to public safety.

The Tribune spoke with three people familiar with the system to obtain a clearer picture of the incident and its ongoing ramifications.

Natural gas moves from the fields and wellheads where it is produced via gathering lines that take it to refineries or, depending on its purity, to the next stage of pipelines — transmission lines. These secondary lines, also known as trunk lines, are typically 6 to 48 inches in diameter and are pressurized at 200 to 1,500 pounds per square inch, said Kenneth Clarkson of the Pipeline Safety Trust in Bellingham, Wash.

The pipeline that was ruptured north of Pullman on Wednesday is a transmission line. These are owned by companies that deliver natural gas to utilities such as Avista. The utilities then deliver the gas to end users via smaller and lower pressure distribution pipelines.

There are 320,000 miles of onshore and offshore gas transmission and gathering pipelines in the U.S., according to a Pipeline Safety Trust briefing paper, and more than two million miles of natural gas distribution lines.

The ruptured pipeline is owned by the Williams Companies.

"Williams is like a giant international conglomerate that owns major infrastructure projects and in particular a lot of gas distribution, so they are a major gas line company," said Ben Otto, a Boise-based consultant for the Northwest Energy Coalition.

Known as the Lewiston Lateral, the line provides gas to Avista's distribution system in places like Pullman, Moscow, Lewiston and Clarkston, said Scott Rukke, director of the Washington Utilities and Transportation Commission. His agency regulates pipelines in partnership with the federal Pipeline and Hazardous Materials Safety Administration.

"Laterals generally run a certain distance and then dead-end," he said.

That is the case with the Lewiston Lateral, which stops at its namesake. Many transmission lines can carry gas in either direction and some are built with two lines side by side so that if one is damaged, service can be switched to the other. But Rukke said that is not the case with lateral lines.

The handoff of gas from transmission lines to distribution lines and in this case from Williams to Avista happens at what are known as city gates.

"It's almost literally like a gate where they (utilities) tap into a big fat interstate pipeline and draw off of it for local service," said Otto.

He called it a complicated system that has been constructed over time and, because of the expense of building and burying pipelines, makes the system difficult to change or modernize. Otto said this incident and others are a good reason to move away from natural gas.

"It is one of the things we talk about when we talk about decarbonization and going all electric," he said. "You remove the risk of this explosive fuel running into people's homes."

Pipelines can be dangerous. The Pipeline Safety Trust was formed after a gasoline pipeline leaked a quarter of a million gallons of gasoline into a creek that runs through Bellingham. The gas ignited into a huge fireball that caused massive destruction.

"It burned and killed everything within a couple-mile radius including three boys," said Clarkson.

His organization serves as a pipeline watchdog and advocates for rules to improve pipeline. For example, Clarkson said federal rules do not require the depth of buried pipelines to be monitored and maintained.

Excavation accidents are the third-most common cause of pipeline incidents, behind only corrosion and the failure of pipeline equipment, according to data from 2010 to present collected by the Pipeline Safety Trust. Clarkson noted an excavator that ripped into a Williams Pipeline at Middleton, Idaho, last month caused an explosion and the subsequent temporary evacuation of 10,000 residents.

"It brings up questions about Williams' public awareness campaign to prevent incidents such as this," he said.

Rukke said according to an initial investigation the person pulling the plow that gashed the Lewiston Lateral did not notify authorities before the work.

"This wasn't a pipeline failure. It was more of a damage prevention failure," he said.

Buried transmission pipelines are marked with 4-foot high yellow posts. As a general rule, Rukke said when standing at a marker, you should be able to see the next one along the line.

"There were markers there," he said, but added, "they weren't in the field. Markers don't last in farm fields. They usually put them on the end of the field or where they are not going to get damaged."

The agency conducts survey flights over the Lewiston Lateral two times each month to look for nearby construction activity or encroachment on the pipeline.

"I have flown that pipeline numerous times. It is beautiful country," he said.

Barker may be contacted at ebarker@lmtribune.com or at (208) 848-2273. Follow him on Twitter @ezebarker.