Backed by the powerful corn lobby, Marquis Energy’s push to bury carbon emissions underground has sparked a fierce debate in Illinois politics. The ethanol plant is banking on carbon capture technology to secure federal tax credits.
Note: This story was updated 10:23 a.m. Jan. 27, 2025.
Nestled along the curves of the Illinois River just outside the town of Hennepin is the country’s largest dry-mill ethanol plant, where a network of pipes, grain elevators and exhaust towers rise like a mini-city. Surrounding the plant are hundreds of acres of corn, the state’s top crop often used to make ethanol fuel.
The plant’s owner, Marquis Energy, processes 360,000 bushels of corn each day, making it an important customer for the state’s nearly $21 billion corn industry. A third of Illinois corn is used to make ethanol fuel.
Marquis Energy plans to build a new carbon capture and sequestration project — which would bury millions of tons of the ethanol plant’s air pollution underground — allowing it to expand its ethanol production and secure lucrative federal tax credits.
But the proposal has drawn opposition from some farmers and state lawmakers who worry carbon capture could pollute a nearby aquifer and disturb topsoil as new pipelines are built.
Map by Lauren Cross, Investigate Midwest via OpenStreetMap, with overlays created in Canva. (Investigate Midwest)
Marquis Energy, along with the state’s corn lobby, has responded with millions of dollars in campaign contributions to state lawmakers, an Investigate Midwest analysis has found. Some of its largest recipients have pushed for pro-carbon capture policies and opposed new regulations.
Last year, the Illinois General Assembly approved a temporary ban on carbon capture projects and introduced a new bill to ban the practice around the Mahomet Aquifer in Central Illinois, which is the water source for over half a million people.

However, Senate President Don Harmon, an Oak Park Democrat, used his position as a committee chairman to table the Mahomet Aquifer bill during a November hearing. Multiple observers attending the hearing told Investigate Midwest they believe the bill would have passed if Harmon had allowed for a vote.
Since 2021, Harmon has received $147,500 from Marquis Energy, according to the campaign finance database Illinois Sunshine.
Since 2020, Harmon has also received $17,500 from the Illinois Corn Association, which also opposed the bill.
A spokesman for the Senate said Harmon was unaware Marquis Energy opposed the bill to protect the Mahomet Aquifer.
“I support additional safeguards to protect our drinking water and the Mahomet Aquifer specifically,” Harmon said in a written statement to Investigate Midwest. “Given the moratorium that’s already in place and uncertainty of the new federal administration, I think it makes sense to pause and see what shakes out in D.C., and then consider our options. Our only priority is protecting clean drinking water.”
Overall, Marquis Energy, a private company, contributed $248,000 to state lawmakers last year, most of which went to Illinois’ four most powerful legislative leaders.
But last year’s contributions are just the latest in a decade-long effort by Marquis Energy and its CEO to shape policy at the Illinois statehouse. Since 2008, the company has spent $1.2 million on state lawmaker campaigns.
Investigate Midwest attempted to contact Marquis Energy by phone and email several times. A spokesperson for the company said they were not interested in commenting at this time.
The Marquis Biocarbon Project site sits on the northern edge of the Illinois Basin. The Mt. Simon Sandstone in Hennepin, Illinois has been identified as the target injection zone for CO2 storage. Also shown are the FutureGen2 and the Illinois Basin – Decatur Project sites, which have demonstrated the capability for CO2 storage in the Mt. Simon Sandstone. This map was listed in Marquis Energy’s biocarbon energy project narrative submitted to the EPA.
Carbon capture proponents claim it fights climate change, expands Illinois corn market
Based on technology originally used to squeeze oil out of nearly depleted fields, carbon capture is the process of converting carbon dioxide pollution into liquid, sending it through a pipeline, and then pumping it nearly a mile underground.
Marquis Energy’s specific plans are to inject CO2 over a five-year period to only about half a mile underground, according to the Illinois State Geological Survey.
Carbon capture and sequestration may someday be considered a normal part of waste management, like garbage removal or sewage treatment, said Holly Jean Buck, a climate politics sociologist at the University at Buffalo in New York.
Some see carbon capture as an answer to climate change. Storing carbon dioxide emissions underground can prevent the gas from warming the atmosphere.
Diagram depicts the carbon capture and storage (CCS) process, from capturing CO2 at industrial facilities to its transportation, injection, and long-term storage in underground formations with depth of storage approximately one mile underground. (EPA)
Diagram shows the structure of a Class VI well used for geologic sequestration of CO2. It includes safeguards like cement and casing to protect underground drinking water sources (USDWs) and illustrates the CO2 plume within the deep injection formation. (EPA)
However, expanding Marquis Energy’s use of carbon capture, which in turn increases the use of ethanol fuel, means continued use of the fossil fuel industry at a time when Illinois and the federal government are trying to incentivize electric vehicles as a way to fight climate change, said Silvia Secchi, an economist and geographer at the University of Iowa.
“It’s a really big problem that we have essentially obsolete Big Ag still driving climate mitigation policy in 2024,” Secchi said. “It’s very much the power of a lobby against the power of science, the way I see it.”
But state Sen. Sue Rezin, a Republican from Morris, believes carbon capture is needed to offset climate change while still being able to meet energy demands.
“In order to reduce our carbon footprint, to achieve our goals that were signed by the state of Illinois, we will have to have carbon capture; otherwise the numbers simply won’t add up,” she said.
Rezin has received $76,100 from Marquis Energy since 2011. In 2021 and 2023, she proposed bills to grant the company pipeline access through public land along the Illinois River. The bills were unsuccessful.
In a written statement provided to Investigate Midwest, Rezin stated that one of her top priorities as a senator is to advance laws “that create jobs, support economic development, and help the industries that are vital to Illinois and my district.”
She wrote that the legislation she introduced “was aimed at expanding opportunities for our state’s agribusiness, utilizing the ethanol industry to its fullest potential, and helping to reduce our carbon footprint.”
The Illinois Corn Growers Association has supported Marquis Energy’s carbon capture push, promoting it as a way to increase the market for Illinois corn.
“With the severe downturn in the ag economy happening today, Illinois corn farmers need additional market demand,” said Brad Stotler, director of public policy for the Illinois Corn Growers Association.
Marquis Energy employed 49 people in 2019, according to Bloomberg. As a private company, it is not required to disclose financial information, such as annual profits or CEO pay.
Opponents worry about water pollution, pipeline leaks
Some Illinois farmers worry that buried carbon dioxide could leak into groundwater, which prompted the Illinois General Assembly to impose a moratorium on CO2 pipeline construction until July 2026, or until the Pipeline and Hazardous Materials Safety Administration comes up with new safety standards.
In March 2024, a leak occurred at one of Archer Daniels Midland’s carbon dioxide wells in Decatur, prompting lawmakers to introduce additional legislation prohibiting carbon sequestration activity over, under or through any sole-source aquifers.
That bill was stalled during its November hearing by Harmon, the Senate leader.
Some witnesses at the hearing questioned whether the ban was necessary.
*Marc Miller, deputy director of the Prairie Research Institute at the University of Illinois, which has studied ADM’s carbon dioxide well since 2011, said future projects would store carbon dioxide more than a mile underground, while the Mahomet Aquifer is just 500 feet below the surface.
“To date, PRI has found no evidence of negative impacts from carbon storage to the groundwater supply,” Miller testified during the hearing.
But state Sen. Rachel Ventura, a Joliet Democrat, is still concerned.
“Even though we have maybe a limestone shale there, there are cracks in it. We have our own holes for things like wells and other pipes,” said Ventura, who co-sponsored the aquifer ban bill. “So the reality is that the gas, over time, will come back to the surface.”
Ventura also co-sponsored a bill last legislative session to ban the use of eminent domain for carbon dioxide pipelines. The bill did not pass.
There’s also concern about leaks along the pipelines transporting carbon dioxide throughout the state. While Marquis Energy’s proposal would sequester its emissions on site, other proposals from out-of-state companies would require hundreds of miles of pipelines carrying carbon dioxide to wells in Illinois.
In 2020, a CO2 pipeline burst in Satartia, Mississippi, sending 45 people to the hospital. Within minutes, carbon dioxide overwhelmed residents, who collapsed in their homes and outdoors.
The dense fog of CO2 also displaced enough oxygen to choke car engines. Cars stalled in the middle of the road as people tried to evacuate. Some drivers who left their cars became disoriented and lost, and others lost consciousness. There were no deaths.
Susan Adams operates a corn and soybean farm in southwest McLean County, about 300 feet from a proposed carbon capture injection well.
“We will be in the immediate vicinity of the pipeline and well when farming that field, and I think that gives us, if there’s a rupture, we would have two minutes to evacuate,” Adams said.

Uncertainty over Trump’s plans for carbon capture tax credit
As the Earth’s surface temperature continues to rise from the use of fossil fuels, Marquis Energy says its plant can achieve “net zero production” through carbon capture.
The company can also receive $85 for every ton of carbon it sequesters through federal tax credits that could total millions of dollars annually. Without the tax credit, companies have little incentive to invest in carbon capture, said Scott Irwin, chair of the University of Illinois’ agricultural marketing department.
President Donald Trump has repeatedly called climate change a hoax, but his picks to lead the Environmental Protection Agency and his proposed National Energy Council have been vocal in their support for carbon capture.
Darrell “Mark” Marquis, CEO of Marquis Energy, spent $110,000 last year on several pro-Trump campaigns, according to federal campaign finance records.
Still, uncertainty surrounds the Trump administration’s plans for the 45Q tax credit for carbon capture. The president has promised to end EPA rules limiting power plant emissions, which may affect whether those industries proceed with their carbon capture plans. However, if the current credit of $85 per ton remains, ethanol companies may still want to cash in.
Some say carbon capture should be focused on more difficult to decarbonize industries, like cement and steel plants, which produce more global carbon emissions.
“Ethanol is the low-hanging fruit. They aren’t really solving a difficult problem,” said Tracy Fox, who is with the Coalition to Stop Predatory Pipelines, an Illinois-based group opposed to CO2 pipelines.
But beyond the science and environmental arguments over carbon capture, many see ethanol as purely a local economic issue.
Reducing Marquis Energy’s ethanol production would be detrimental to many Illinois farmers, said Betsy Rowland, who farms 8,000 acres of corn and soybeans in Bureau County.
“If something were to happen to those ethanol plants, they wouldn’t just be the farmers that were hurting,” she said. “There’s not a lot going on in Bureau County job-wise besides agriculture, and to have something happen to those plants would really hurt the community.”
*CORRECTION: This story has been updated to reflect Marc Miller’s title as deputy director of the Prairie Research Institute.
This article first appeared on Investigate Midwest and is republished here under a Creative Commons license.
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