Natural gas supplies in the upper Midwest are returning to normal after a disruption caused when a Canadian gas pipeline exploded over the weekend.
The gas supply shut down about 1 a.m. Saturday, when a pipeline exploded about 30 miles north of the Canadian border. The explosion and resulting fire caused TransCanada Corp., an energy company, to close two other pipelines.
That reduced the supply to Viking Gas Transmission, a pipeline company that provides gas to Midwest utilities. Although Viking asked its suppliers to send more gas from other locations, utilities quickly asked customers to conserve energy by turning down thermostats.
Xcel Energy North Dakota manager Mark Nisbet said the utility will study this incident in detail, but he said it appears the system worked.
"This is a pretty rare incident, but it was encouraging that the backups were there and routing gas from a lot of different areas," he said. "There are things called peaking plants that inject gas into the system if things like this happen."
Even with temperatures dropping Sunday night, gas use did not go as high as expected because consumers responded when Xcel asked them to reduce demand.
"We start with our large and industrial customers and you see some immediate impact there," he said. "And with the residential customers what it amounted to is us building to an unsustainable peak when you get down in the 20-below temperature."
If demand is greater than supply, Nisbet said, pressure in the pipes drops. That can cause furnace and hot water heater pilot lights to go out. Xcel had extra crews on standby in case they needed to go door to door and re-light pilot lights.
The strong supply of natural gas in the Midwest, delivered through pipelines from the south, west and Canada, also helped the system work. Having a variety of sources kept natural gas moving, said Dan Kish, senior vice president of policy at the Institute for Energy Research in Washington D.C.
"The system that delivers our natural gas is extremely complex and inter-tied throughout the country," Kish said. "If you lay it down it looks like a map of the United States and North America generally with spaghetti thrown on it."
Despite the network of natural gas pipelines, more pipelines are needed, Kish said.
"In the Bakken and throughout the regions where there's increased production, pipelines need to be built and they need to be built more quickly," he said. "It is a shame that we have to flare gas when it could be going into a pipeline and helping relieve pressure on consumers."
The temporary disruption in the Canadian pipeline is not likely to cause a natural gas price spike in Minnesota and North Dakota, said Angelina LaRose, who heads the natural gas markets analysis team for the U.S. Energy Information Administration.
"Really what we're seeing in natural gas markets is really the cold weather that we're having in the Midwest as well as the Northeast is what's putting pressure on prices and increasing demand," she said.
Even if prices do rise some, Midwesterners might not want to complain too loudly. In the Midwest, one million BTUs of gas costs $10. In New York, consumers pay $60 for that amount, LaRose said. A big reason for that disparity in pricing is the pipeline system that distributes natural gas to the Midwest.
"There's a lot of different pipelines bringing in supply to that area," LaRose said. "What you see in the Northeast, particularly New England is considered more what we could call the end of the pipeline."
Canadian officials say it will take a few days to complete repairs on the damaged pipeline.
In the big picture, LaRose said, it will be only a minor disruption in the system.