Illinois Lawmakers Vote to Limit Carbon Sequestration Near a Major Aquifer – Inside Climate News

A bill passed by the Illinois legislature could slow the growth of carbon sequestration proposals—and proposals, in particular, for projects located near an aquifer that is the sole source of drinking water in some communities.  

If Gov. JB Pritzker signs the law, hundreds of thousands of residents in central Illinois who rely on the Mahomet Aquifer will not see any new sequestration projects that would pump carbon dioxide through, over or under the underground reservoir. 

The geology in Illinois is particularly well-suited as a reservoir for carbon sequestration, in which companies turn carbon dioxide into a liquid and store it underground, a process that could help address the concentration of greenhouse gases in the atmosphere that contribute to climate change. Aquifers are natural underground formations that can hold vast pools of drinking water, and supporters of the law were apprehensive about the effects of industrial pumping and sequestration close to the basins.

Three companies have submitted proposals in the last few years to store carbon dioxide under or pipe it through the Mahomet Aquifer, which supplies water to about 800,000 people.

“As the threat of a carbon sequestration project loomed over that area, I had to act,” said Rep. Carol Ammons (D-Urbana), who proposed the bill. “Our tolerance for risk in that situation had to be zero.”

Illinois environmental advocacy groups, including the nonprofit Eco-Justice Collaborative and the nonprofit Prairie Rivers Network, backed the measure. They warned of possible dangers to the water source if carbon leaks or escapes. Carbon dioxide could form carbonic acid, change the water’s pH and release toxic metals, they cautioned.

“I personally believe, and so do our colleagues, for the most part, that there are better solutions to climate change than this one,” said Pam Richart, co-director of Eco-Justice Collaborative.

The legislature has acted twice in two years to address potential consequences of carbon sequestration. 

In 2024, legislators enacted a two-year moratorium on new carbon sequestration pipelines through the SAFE CCS Act, which also addressed loopholes in federal regulations. Advocacy groups wanted additional protections for the aquifer included in the law, but those fell out in debate. Still, advocacy groups celebrated the version signed by the governor.  

Later that year, however, the federal Environmental Protection Agency cited the Chicago-based Archer-Daniels-Midland Co., the multinational food processing and commodities trading corporation known as ADM, for violating federal drinking standards at a sequestration facility in Decatur, southwest of Champaign. 

ADM had a leak at a monitoring well and didn’t follow proper emergency protocol and remediation once it detected the leak, the EPA found. ADM did not respond to requests for comment for this story.

The Decatur project was the first of its kind and had been previously seen as a success once it began pumping carbon dioxide into the ground in 2011, sequestering 4.5 million metric tons of the gas over 11 years. The discovery of that leak and then another soon after prompted environmentalists and many residents to push hard on water safety concerns. 

“People realized that that leak had happened while the CCS bill was being negotiated,” Richart said. “That helped us get the attention that we needed to move this across the finish line.”

She and others also wanted protections in the bill for recharge areas, places where surface water filters into the ground and replenishes the aquifer—something that was not ultimately included. “The water in that area resupplies the aquifer, and we thought it would make sense to extend protections to those areas,” said Andrew Rehn, climate policy director for Prairie Rivers Network.

Some argue that the current requirements safeguard drinking water.

“There are regulations that exist already that we would adhere to, that protect the Mahomet, and it’s not clear really what this additional ban was intended to do,” said Steve Whittaker, the vice president of subsurface for Vault 44.01, a carbon storage development company that submitted a proposal for a carbon sequestration well that would be affected by the legislation. “It’s just an anti-CCS bill.”

Carbon sequestration projects in Illinois have moved forward in fits and starts since 2003, when the U.S. Department of Energy and the state of Illinois announced a public-private project with FutureGen Industrial Alliance, a group representing power and coal industries.

Carbon dioxide emissions from a coal plant would be captured and sequestered in the first project of its kind at a cost of $1.65 billion for four storage wells in Mattoon, a town of 16,000 people southeast of Decatur. Yet costs ballooned, leading President George W. Bush to end the project. Two years later, the project restarted on a smaller scale. Lawsuits delaying FutureGen 2.0 prevented the project from being completed before federal funding expired, and the Department of Energy terminated it again in 2016. 

Still, geologists estimate that there is plenty of potential in Illinois for carbon storage. 

The Illinois Basin is a sandstone formation capped by sedimentary rock that underlies a sea of farmland in the state. Scientists have estimated that the basin could store between 12 and 172 million metric tons of carbon dioxide. That could significantly abate the region’s carbon dioxide emissions, said Randy Locke, chief scientist for research and development at the Illinois State Geological Survey.

Locke said carbon sequestration is a technology that can be used safely when permitted and operated correctly, but not every part of the basin is suitable for sequestration. He said ongoing research by geologists should give the state a more detailed understanding of the best locations for wells, potentially within the next year.

“Our intent is to try and continue to gather information and research on these things so that if CCS is going to be deployed and deployed at scale, we want it to be deployed as safely as possible,” said Locke. “That can only be done with effective information gathering and deliberation and assessment and sharing that to all stakeholders.”

The new bill also requires that the state conduct a five-year study on carbon sequestration to determine any additional risks. What state researchers find could help lawmakers decide whether there is a need for further guidelines, particularly if the EPA has fewer resources due to budget cuts made by the Trump administration.

“There are a lot of question marks, a lot of things—good and bad—that have been untested so far,” said Rehn of the Prairie Rivers Network. “We’ll have to learn from those and see how our protections play out.”