Mine work at Westmoreland’s Rosebud Mine near Colstrip. Credit: Alexis Bonogofsky

Montana Attorney General Austin Knudsen this week joined 20 other attorneys general urging the U.S. Environmental Protection Agency to scrap a proposed rule that seeks to dramatically decrease carbon dioxide emissions in the energy sector.

In a 55-page letter dated Aug. 8, the signatories argue that a rule the Biden administration unveiled in May amounts to an unlawful overstepping of the EPA’s authority and an attempt to circumvent a 2022 U.S. Supreme Court decision. That ruling took a dim view of the executive branch’s efforts to use the Clean Air Act for “generation-shifting,” or transitioning the energy sector away from climate-warming fossil fuels.

When the rule came out, the EPA described it as an action that would “protect public health, reduce harmful pollutants and deliver up to $85 billion in climate and public health benefits over the next two decades.” In a fact sheet about the rule, the agency wrote that the power sector is the largest stationary source of greenhouse gas emissions and that it was responsible for 25% of domestic emissions in 2021. The rule would establish new limits on greenhouse gas emissions for most new and existing coal-, gas- and oil-fired power plants, leaning on “proven and cost-effective control technologies” to reshape the energy sector. 

“[The standards] also provide owners and operators of power plants with ample lead time and substantial compliance flexibilities, allowing power companies and grid operators to make sound long-term planning and investment decisions, and supporting the power sector’s ability to continue delivering reliable and affordable electricity,” the EPA wrote.

The proposed standards are tiered such that fossil fuel plants that operate more frequently would be subject to higher emissions standards, which would begin in 2030 and become increasingly stringent.


The letter the 21 attorneys general submitted in response to the rule took aim at both the question of the EPA’s authority to enact such standards absent congressional approval and the efficacy of technologies proposed to strip power plant emissions of carbon dioxide — namely carbon capture and storage and the use of hydrogen to reduce carbon emissions. 

Carbon capture and storage or sequestration is likely to stay “one decade away” from being ready for industrial-scale use, the attorneys general wrote, “despite extravagant financial support.” The industry has “no chance of meeting” the standards proposed, they continued, likening the EPA’s proposed rule to the Clean Power Plan, which was issued by former president Barack Obama in 2015, stayed by the U.S. Supreme Court in 2016 and later repealed by the EPA.

“It would force plants to close and compel a switch to lower-emitting fuel sources such as wind and solar — making it a de facto generation-shifting mandate” the letter reads. “So in much the same way the [Clean Power Plan] did, this Proposed Rule exceeds EPA’s delegated authority.”

If adopted, the EPA’s rule would have economic and technological implications for the Colstrip coal-fired power plant, which is the nation’s 15th largest carbon dioxide polluter among all power plant sources and the only regularly operating coal-fired power plant in Montana. Others, like a 44-megawatt plant in Sidney formerly operated by Montana-Dakota Utilities, have shuttered in recent years, with owners citing the expense of running them and required plant upgrades.

NorthWestern Energy, Montana’s largest regulated utility, struck a deal in January to double its share in Colstrip, which is jointly owned by six companies, mostly Washington- and Oregon-based utility companies. All other co-owners, except Talen Energy, plan to exit the plant within the decade. 

In a statement to the Billings Gazette, NorthWestern Energy noted that 59% of its generation is carbon-free (largely due to the extensive hydroelectric generation in its portfolio), and it remains “committed to building on this progress to reach our commitment of net-zero carbon emissions by 2050.” 

“NorthWestern Energy’s thermal resources, including Colstip and the Yellowstone County Generating Station, are critical to support Montana’s energy transition,” the statement said, “and add more renewables to the grid until reliable generation and storage technologies become commercially available at cost and scale.”

Families for a Livable Climate, a Missoula-based organization acting on climate and energy issues, praised the EPA proposal in a website post on Aug. 2. 

“If adopted, these regulations would cut 617 million tons of carbon pollution and would force energy providers to move to cheaper, cleaner energy — for which the recently passed Inflation Reduction Act provides billions of dollars of funding,” the group wrote, adding that an accelerated timeline for closing non-compliant plants would be preferred.

In June, the EPA extended the comment period for the proposed rule, which closed on Aug. 8, the date of the letter issued by Montana Attorney General Austin Knudsen and his colleagues from other states, including Texas, West Virginia and Louisiana. Knudsen has been at odds with the Biden administration over multiple energy-related issues, ranging from the Keystone XL pipeline to federal oil and gas leasing policies.


Amanda Eggert studied print journalism at the University of Montana. Prior to becoming a full-time journalist, Amanda spent four years working with the Forest Service as a wildland firefighter. After leaving the Forest Service in 2014, Amanda worked for Outside magazine as an editorial fellow before joining Outlaw Partners’ staff to lead coverage for Explore Big Sky newspaper and contribute writing and editing to Explore Yellowstone and Mountain Outlaw magazines. Prior to joining Montana Free Press’ staff in 2021 Amanda was a freelance writer, researcher and interviewer. In addition to writing...