Fire fuels concerns over Consumers' natural gas system
Last week's fire at a Consumers Energy compressor station in Macomb County during a record-breaking cold snap exposed vulnerabilities — as well as strengths — in the system that supplies natural gas to 4.1 million Michiganians, experts say.
The Jan. 30 blaze crippled the utility's Armada Township facility, which supplies 64 percent of Consumers' natural gas, leading Consumers to ask some large industrial customers to shut down and Gov. Gretchen Whitmer to ask residents to turn down their thermostats to preserve a suddenly constricted supply.
And while the company's distribution system weathered the crisis, some experts believe such a breakdown will happen again — if not in Michigan, then elsewhere.
Carl Weimer, executive director of the Bellingham, Washington-based Pipeline Safety Trust, which monitors natural gas pipeline issues nationally, said Consumers Energy handled the crisis appropriately, but added that the incident was not unique.
More than 6,500 residents and business in Newport, Rhode Island, lost power last month when their gas was shut off when a loss of pressure led to fears of explosions. There is an ongoing safety review of the incident, similar to one in September in Massachusetts that affected 8,000 customers.
“We experienced the same thing, even more widespread, here in the west coast late last year when an Enbridge gas transmission pipeline failed in British Columbia,” said Weimer.
“Big industries like refineries had to shut down, consumers were asked to use less gas, etc.,” Weimer said of the October incident.
“I think this same issue could happen in many areas, since natural gas is moved mainly through linear pipelines, so if anything happens along that line, such as a pipeline failure or a fire in a compressor station, supplies can be severely impacted,” he said.
“Some communities may have more redundant systems with better options to bring in gas from other pipeline systems or from underground or (liquefied natural gas) storage, but I don’t think it is all that rare for an area to be fairly dependent on a single pipeline.”
Michigan wasn't alone in having its natural gas distribution network strained by last week's polar vortex. In Minnesota, about 150 homes lost service and Xcel Energy Co. asked all customers to lower their thermostats Wednesday night, the Minneapolis Star Tribune reported.
In the wake of last week's crisis, Whitmer on Monday asked the Michigan Public Service Commission to review the state's energy supply and distribution systems and report findings by July 1. The commission, which regulates the state's utility companies, is investigating the fire, agency spokesman Nick Assendelft said.
Charlotte Jameson, energy policy and legislative affairs director of the Lansing-based Michigan Environmental Council, said the Armada Township incident focuses attention on the state’s growing dependency on natural gas for heat.
According to the U.S. Energy Information Administration, 78 percent of Michigan residents use natural gas for heating.
“I don’t want to draw any conclusions, but the fact that Consumers is so dependent on this compressor station raises concerns around both oversight and planning of the gas infrastructure system,” she said.
Michigan's dependence on natural gas appears to be growing, Jameson said, noting that DTE Energy began construction in August on a natural gas plant in East China Township.
“DTE was approved last year to build a $1 billion gas plant," she said. "That move means we as a state will be even more dependent on gas and on gas distribution network.
“Again I think this is a concerning road to go down when it is clear, from this example in Michigan and nationwide, that gas infrastructure is vulnerable to fire, damage and shutdowns,” she said. “Diversifying our energy and heating mix — bringing in more solar, wind, and battery storage — and reducing gas use through energy efficiency and gas efficiency programs will help us weather and/or avoid these sorts of emergencies going forward."
Consumers has 2,500 miles of large gas transmission pipes and 28,000 miles of smaller lines in Michigan — the most in the state. It supplies natural gas to 1.7 million homes and businesses in 45 of Michigan's 83 counties, with a service area that covers much of Metro Detroit, south-central and mid-Michigan.
Consumers' closest competitor in Michigan, DTE has 2,000 miles of large gas transmission pipeline and 19,000 miles of smaller line. DTE supplies natural gas to 1.3 million customers in 49 of the state's counties, including parts of Metro Detroit, sections of the Upper Peninsula and much of western and northern Lower Michigan.
Consumers operates roughly 48 percent of the state's gas service lines, DTE operates about 37 percent, and the rest are run by smaller utilities, Assendelft said.
Jameson said in terms of its natural gas supply, Michigan is not uniquely vulnerable.
“In fact, we have the largest gas underground storage capacity in the nation and the second-largest number of natural gas storage fields,” she said. “The question in this emergency is a question of adequacy of distribution to get the gas where it needs to go.”
She explained that gas has to be pressurized as it travels inside a pipeline. As gas moves over long distances, elevation and friction cause it to lose pressure.
“Compressor stations are key because they repressurize the gas,” she said. “Utilities are supposed to place compressor stations strategically throughout the distribution system to compress the gas to the correct pressure and allowing the gas to keep traveling along the system. The general rule of thumb is to locate them about every 40 to 70 miles on a pipeline.
“These are complex systems and any time you are bringing heat, pressure and combustible fuel close to one another, you run the risks,” she said. “The engines and turbines that are used to compress the gas produce heat, which has to be vented, and the compressed gas has to run through a cooling system before it goes into the pipeline. Across the country, we have seen numerous explosions and fires at gas compressor stations. The difference in this situation was the unusually high demand for gas due to the cold weather.“
Jameson said Michigan — one of the top five states for residential use — “should use this as an opportunity to think heavily about our dependency on gas …”
“Do we really want to continue to put all of our eggs in this basket?” Jameson asked. “Especially as climate change increases the number of extreme weather events, we should be diversifying heating options and creating programs that help residents and businesses move to electric, especially as the price of electric heat pumps comes down and their efficiency increases.”
“We think Governor Whitmer took the correct step to direct the Michigan Public Service Commission to review our state's energy preparedness and the supply and delivery of gas,” said Jameson. “We think there is lots of room for improvement both in terms of hardening our system to improve public safety and to reduce our overall dependence on gas going forward.“
In an interview Wednesday, Consumers senior vice president of operations Garrick Rochow said the company believes the blaze started when a fire-detection system in one of the facility's three plants activated, apparently perceiving a fire.
"There was none, but under the system, gas is vented out of the stack and for some reason it ignited and the stack caught fire," he said. "Following that, buildings two and three also tripped into firegate mode."
The venting and ignition of gas caused at least two loud and visible fireballs that some witnesses mistakenly believed were explosions, Rochow said. The company is investigating why the fire detection system activated and why the stack caught fire while gas was vented.
The Ray Compressor Station, which covers 4.9 acres and has 41.2 billion cubic feet of storage, is Consumers Energy’s largest underground natural gas storage and compression facility.
Chris Kobus, an associate professor of engineering at Oakland University, said it appears Consumers Energy weathered a “perfect storm” of fire, low compression and heavy user demand.
“Every state is unique in how they store gas — either below or above ground — but in Michigan there is a rather large underground storage area in Macomb County which is used by Consumers,” said Kobus, who is also director of the school’s Clean Energy Research Center. “It is a good, reliable system. You don’t have 30 pumps working on providing gas delivery, as in some states, but the downside is when you have a problem you have a big one.
“Like any facility, they have backup systems but they don’t operate as well,” Kobus said. “You have great demand and this is the problem. You start losing pressure in the lines and when that happens you risk not getting enough pressure for furnaces to operate. And if they stop, like in frigid weather like we have been experiencing, you have a whole assortment of other problems including water pipes freezing and breaking.
“I haven’t all the details but from everything I have heard, I think they did the right thing and it worked.”
Consumers Energy said it was never in danger of running short of natural gas; rather, its main concern was avoiding a loss of pressure to customers.
“We had plenty of gas to supply our customers but the incident at the Ray Compressor Station restricted our ability to get the gas moved through our system and to homes and businesses,” said Katie Carey, director of Consumers media relations. “We did not believe there was a danger of an explosion.”
She referred to the incident as a “first of its kind in our company’s more than 130-year history.”
“It truly was an extraordinary event,” Carey said. “We have already put several strategies into place to help mitigate the possibility of this happening again, and we will apply any learnings from our root cause analysis to further enhance our natural gas system.”
When asked why Consumers waited 12 hours after the fire to ask residential customers to cut back usage, Carey said the blaze occurred about 10:30 a.m. Jan. 30 and at 1 p.m. the utility company was calling its largest commercial and industrial customers “to reduce usage."
“By midafternoon, that appeal became a mandatory curtailment for those largest customers,” she said. “At 2 p.m., we started making a public appeal to all of our customers to voluntarily reduce their natural gas use. However by dinner time, we were not seeing the progress we needed …”
That led to a public appeal via Facebook and a statewide emergency alert urging residential users to turn their thermostats down to 65 degrees.
That resulted in a 10 percent reduction in gas usage, which Carey described as a “game-changer for us.”
“We are extremely grateful to all those customers and residents who heeded our call to reduce use. ... Had usage not been reduced, there was the possibility that some of our natural gas customers could have lost service."
Asked how the utility would have managed service cutoffs and decided who would have been affected, Carey said only, “We have the ability to manage the flow of natural gas through our system. Fortunately with the help of our customers, we did not have to take further action.”
Carey cited a tariff agreement with the state that includes provisions for curtailments in “emergency situations such as that experienced this past week.”
The agreement requires the company to follow a priority list when curtailing gas deliveries to customers, starting with nonresidential customers who have alternate fuel capability. It then moves to commercial and industrial gas users, beginning with the largest users and working down to the smallest.
The priority list ends with residential users, small commercial users and “services essential for public health and safety not covered by an alternate fuel.”
“Consumers Energy did not physically shut off any customers,” Carey said. “Rather, Consumers Energy worked with customers in order to implement the gas curtailment pursuant to the MPSC curtailment tariff, which allows curtailed commercial and industrial customers to maintain gas service to ensure plant protection and services essential for public health and safety.“
Rochow compared the company's gas pipeline network to the circulatory system in the human body where the fingers and toes, the farthest from the blood-pumping heart, are the first to feel the cold when blood pressure drops.
In a worst-case emergency, when sufficient gas pressure could not be maintained to the most distant destinations, those customers would be the first to be shut down, he said.
“You don’t really get to choose,” Rochow said.
If shutoffs are needed, a utility "shall provide notice to the (Michigan Public Service) Commission and all affected customers of the nature, probable duration and extent of such … curtailment," according to commission regulations. "Such notice will be given as far in advance as possible."
DTE also called last week for users to reduce electricity usage during the arctic blast to “help safeguard the reliability of the regional energy grid” at the request of the Midcontinent Independent System Operator, which oversees electrical transmission across several states, including Michigan.
On the afternoon of Jan. 30, DTE also helped supply Consumers with natural gas through an interconnection point in southeast Michigan.
"All of our electrical and natural gas systems worked as planned,” DTE spokeswoman Jill Wilmot said. “We were able to provide safe and reliable natural gas to our customers.”
Breana Noble contributed.