Minnesota state utility panel says CO2 pipelines should be regulated

Minnesota utility regulators Thursday deemed carbon dioxide pipelines as hazardous, meaning they must get state approval to be built.

The unanimous decision affects two multibillion-dollar CO2 pipelines slated to cross Minnesota, transporting CO2 waste from several ethanol plants in the Midwest.

The Minnesota Public Utilities Commission (PUC) must approve pipelines that carry hazardous materials — oil for instance — but state law does specifically list carbon dioxide as hazardous. PUC commissioners interpreted the 1988 law as including CO2 pipelines.

The PUC will now initiate a rulemaking process, which will likely take a year, to codify CO2 as a hazardous pipeline material for regulatory purposes. Actual approval of any CO2 pipeline could take many months after that.

CO2 is considered a hazardous pipeline material under federal law and in other states that would host the pipelines.

The Midwest Carbon Express, proposed by Ames, Iowa-based Summit Carbon Solutions, would run for 150 miles in Minnesota, connecting to seven ethanol plants. The Heartland Greenway, proposed by Texas-based Navigator CO2 Ventures, would jog 12 miles into Minnesota, linking to one ethanol plant west of Fairmont.

The PUC left open a possible exemption for Navigator's pipeline since it only goes through one county. In its rulemaking, the PUC will look at exemptions for CO2 pipelines of "de minimis" lengths. Currently, individual counties would approve both pipelines.

Tuma said a "de minimis" exemption would make sense, particularly since the CO2 pipeline companies would not have eminent domain power in Minnesota.

The pipeline companies would collect CO2 emissions from ethanol plants and store it underground — below drinking water aquifers — in North Dakota for Summit and in Illinois for Navigator.

Several state agencies submitted comments to the PUC favoring state regulation, including the departments of public safety, commerce and transportation. So have environmental groups, Indian bands and labor unions.

"We would encourage you in your review to use common sense," Kelly Applegate, the Mille Lacs Band of Ojibwe's natural resources commissioner, told the commission Thursday. "If there is a breach in this pipeline there will be violent plumes of gas that could suffocate people and animals."

CO2 is heavier than air, so if a pipeline ruptures it can collect in low-lying areas and displace oxygen. It's a potential asphyxiant and can cause breathing difficulties, rapid heartbeat, vomiting, headaches and impaired thinking.

The worst U.S. accident on a CO2 line appears to have occurred in 2020 near Satartia, Miss. A 24-inch pipeline owned by an oil and gas company ruptured, leading to the evacuation of more than 300 people. Forty-six were treated for injuries at local hospitals.

No known fatalities have been reported from any CO2 pipeline incidents in the United States.

While CO2 is not flammable, it's heavily pressurized in pipelines, leading to the possibility of "ductile fractures" that rip open a pipeline if there's a leak.

"There aren't small leaks in any of these pipelines," said Hudson Kingston, policy and litigation attorney for Public Employees for Environmental Responsibility, which pushed for PUC regulation. "When it blows up, it blows up."

"These are highly pressurized gases that meet that meet the definition the Legislature set out," Kingston said.

Kingston was referring to a provision in state law granting PUC authority over pipelines designed to operate "at a pressure of more than 275 pounds per square inch and carry gas." CO2 pipelines operate at three to four times that pressure.

The PUC sided with that argument.

"If it is over 275 psi, it seems the Legislature is saying it is dangerous," Tuma said.

The pipeline companies argued CO2 is not approved for regulation.

The law "lists very specific materials" as hazardous for pipeline transport — and CO2 is not one of them, said Christina Brusven, an attorney representing Summit Carbon Solutions. "What I don't want is for the commission to engage in a yearlong rulemaking process only to find out the commission doesn't have the authority to regulate a CO2 pipeline."

The pipeline companies also argued that CO2 has the characteristics of a liquid — not a gas — when it's being transported.

Pressurized CO2 is in a "supercritical state" when it's moving through a pipeline, meaning its chemical phase boundaries have faded; it has the properties of both a liquid and a gas. If a pipeline is breached, CO2 vaporizes and can also turn to a solid like dry ice.