Wisconsin Attorney General Josh Kaul has joined a multistate coalition suing the U.S. Environmental Protection Agency over its repeal of federal greenhouse gas standards for power plants, Wisconsin Public Radio reported.

The complaint targets the EPA's 2025 rescission of the Greenhouse Gas Power Plant Rule, finalized in April 2024 under the Biden administration. That regulation imposed declining carbon intensity limits on existing coal- and new natural gas-fired units, with a deep-decarbonization trajectory for the U.S. power sector by 2032. Wisconsin's participation lifts the plaintiff count to roughly a dozen state attorneys general now pressing the case.

What did the repealed rule require?

The 2024 standard capped carbon emissions from long-term existing coal plants at approximately 880 pounds per megawatt-hour by 2032, with new baseload gas units held to about 850 pounds. New intermediate load gas units faced a separate subcategory with looser limits. The Trump EPA repealed those thresholds, citing statutory authority concerns, projected retail rate increases of several percentage points, and grid reliability risks.

The agency's rescission changed the operating environment for older coal assets. Operators now face weaker federal pressure to retire uneconomic units, retrofit carbon capture, or shift dispatch toward lower-emitting fuels. Several utilities had already mapped retirements against the 2024 compliance curve; that planning horizon is now in question.

Why does the rule matter for material streams?

The air-quality rule sits upstream of several material flows that the circular economy tracks. The power sector generates roughly 110 million short tons of coal combustion residuals per year in the United States — fly ash, bottom ash, and flue gas desulfurization material. The pace of coal retirements and ash generation directly shapes the supply side of the fly ash reuse market for cement and concrete, where substitution for virgin material is a core circularity lever.

Other connections:

• Scrap metal from decommissioning. Coal plant retirements release steel, copper, and turbine components into secondary commodity markets. Slower retirements delay that feedstock.
• Pollution-control equipment turnover. Loosened emission limits reduce demand for new fabric filters, scrubber internals, and selective catalytic reduction hardware.
• Renewable component demand. The cost gap between fossil and clean generation influences buildout rates for wind and solar, driving demand for aluminum, steel, and rare earth permanent magnets.

The repeal extends the operating life of material flows the recycling sector would otherwise have absorbed earlier.

What happens next in court?

The D.C. Circuit Court of Appeals is expected to consolidate the state AGs' challenge with parallel suits filed by environmental groups and municipal utilities. D.C. Circuit briefing schedules typically run six to nine months, placing oral arguments in the late-2025 or early-2026 window absent expedited treatment.

A merits ruling will decide whether the 2024 GHG standards remain enforceable, or whether the EPA retains discretion to forgo power-sector carbon regulation under Section 111 of the Clean Air Act. The Supreme Court has not signaled any intent to take up the dispute.

The EPA continues to advance separate rulemakings touching power plant material streams. The agency is reviewing its 2024 coal combustion residuals landfill rule and considering updates to the Mercury and Air Toxics Standards, both of which sit in the Federal Register pipeline.

The next regulatory milestone

The decisive date for industry planning is the D.C. Circuit's consolidation order and briefing schedule, expected within roughly 60 days. Until that schedule issues, generators, ash marketers, and scrap processors face regulatory uncertainty that affects retirement schedules, emissions-control capital expenditure, and contract pricing of fly ash supply through 2026.