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PERI Greenhouse 100 Polluters State Press Release For Wisconsin

November 6, 2025

 

With Future Data in Doubt, UMass Amherst Political Economy Research Institute Names Top U.S. Climate Polluters

Rollback in EPA reporting requirements may end Greenhouse 100 Polluters Index and access to vital public information

AMHERST, Mass. — Researchers at the University of Massachusetts Amherst’s Political Economy Research Institute (PERI) today published a new Greenhouse 100 Polluters Index, reporting 2023 greenhouse gas emissions using the latest—and possibly last—data available from the U.S. Environmental Protection Agency’s Greenhouse Gas Reporting Program.

On Sept. 12, the EPA announced plans to end most of the program and suspend all remaining reporting requirements until 2034. The decision could leave the public without reliable, standardized data on corporate climate pollution for nearly a decade.

“The Greenhouse 100 Index informs consumers, shareholders, regulators, lawmakers and communities about corporate releases of climate-altering pollutants into our environment,” says Professor Michael Ash, co-director of PERI's Corporate Toxics Information Project. “The EPA’s decision to effectively end the Greenhouse Gas Reporting Program removes access to vital public information and leaves public and private decision-makers flying in the dark or relying on a patchwork of voluntary and potentially cherrypicked or greenwashed reports.”

Launched in 2018, PERI’s free, open-access online tool provides data on every company that reports to the EPA. The resource includes state-by-state rankings and detailed reports identifying all companies and facilities responsible for each state’s greenhouse gas emissions. Archives of earlier editions remain available to the public.

The following is PERI's analysis for Wisconsin.

Overall

Summary for WisconsinValue
Total 2023 CO2 equivalent emissions (millions of metric tons):39.5
Percentage of national total:1.5
Rank among US states (1=top):22

Top 5 Polluter Companies in Wisconsin

CompanyCO2 equivalent emissions (mmt)% of state totalNum. facilities
WEC Energy Group19.050.317
Alliant Energy10.327.28
Dairyland Power Cooperative1.95.13
GRAYMONT LTD1.02.73
Bain Capital0.82.05

Top 5 Sectors in Wisconsin

Sector NameCO2 equivalent emissions (mmt)Num. facilities
Power Plants32.034
Other Paper Producers1.620
Lime Manufacturing1.24
Municipal Landfills0.923
Ethanol Production0.810

Top 10 facilities in Wisconsin

Facility NameCO2 (metric tons)Company
Elm Road Generating Station5,879,315WEC Energy Group
Columbia4,621,127Alliant Energy
South Oak Creek3,951,885WEC Energy Group
Port Washington Generating Station3,154,314WEC Energy Group
Weston3,030,740WEC Energy Group
Riverside Energy Center2,867,896Alliant Energy
Edgewater (4050)2,086,756Alliant Energy
Fox Energy Center1,625,577WEC Energy Group
J P Madgett1,546,538Dairyland Power Cooperative
GRAYMONT (WI) LLC521,551GRAYMONT LTD

“In making this information available, we are building on the historic achievements of the right-to-know movement,” Ash adds. “Our goal is to engender public participation in environmental decision-making, and to help residents translate the right to know into the right to clean air, clean water and a livable planet.”

The EPA’s rollback of reporting and disclosure requirements also threatens other PERI indexes that track companies’ release of pollution into the air and water, and near schools.

Contacts:
Michael Ash, mash@umass.edu

Aaron Kupec, akupec@umass.edu