After months of hearings and discussions, the Sangamon County Board seems poised to approve plans for the county’s first data center on March 23 despite consistent pushback from constituents. CyrusOne plans to build a data center campus on 280 acres of farmland, which would have more wattage than any other data center the company currently operates.
CyrusOne already has two other such centers in Illinois, in Aurora and Lombard, but they’re considerably smaller than what’s being proposed in Sangamon County, which would be classified as a hyperscale data center with a 634-megawatt capacity once fully constructed. Although it has dozens of data centers operating across the U.S. and Europe, the largest operational data center that the private equity-backed CyrusOne has built possesses a capacity under 170 megawatts, according to its website.
The Aurora data center is one-fourth the size of the Sangamon plan and has a capacity of 109 megawatts, while the one located in Lombard is comparably miniscule with a capacity of a dozen megawatts.
The Nuclear Regulatory Commission, a federal agency created in 1975 to address nuclear energy safety, cites how one megawatt “equates to about the same amount of electricity consumed by 400 to 900 homes in a year.”
That means 634 megawatts of electricity could provide enough power for anywhere between 250,000 and 570,000 homes annually; Sangamon County has fewer than 100,000 housing units.
County officials have said the project won’t affect consumers’ electric rates and the Rural Electric Convenience Cooperative, which operates the grid the data center would pull electricity from, also claims such a project would not lead to an increase in electricity rates.
“It’s the opposite! Because these operations bring in extra revenue, they help cover system costs, which supports rate stability for all members,” the utility company states in an online FAQ. However, larger utility companies, such as PJM, have acknowledged concerns over data centers impacting ratepayers.
The Illinois Department of Commerce and Economic Opportunity has a program that exempts certain taxes for data center projects that meet particular requirements. Gov. JB Pritzker, in his upcoming budget plan, wants to pause that program for two years to better assess the impact of data centers. The Data Center Investment Program has already given CyrusOne $132.5 million in tax breaks for its Aurora site, roughly $35 million more than what the company would pay in property taxes to Sangamon County over a 20-year period.
Senate Bill 4016, introduced last month as the POWER (Protect Our Water, Energy and Ratepayers) Act by Sen. Ram Villivalam, D-Chicago, would require full environmental assessments for hyperscale data centers. It would also require data center operators to pay fees proportionate to the peak power demand of the center.
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Under the current laws, the Sangamon County project’s only environmental hurdles were in the form of a potential ecological compliance assessment by the Illinois Department of Natural Resources, which was not conducted because there were no identifiable natural resources or endangered species within the proposed area, and a State Historic Preservation office review, which notes the property is not a historical or local landmark.
‘That’s still going to have the potential to cause a lot of impact’
Part of the plans for the data center include more than 400 diesel-powered backup generators that are “tested for 10-15 hours per year for maintenance purposes” and to be used in case of emergencies.
Max Zhang, a professor at Cornell University who researches air pollutants produced by diesel-powered generators, said the plan for 420 diesel-powered backup generators “is the largest number I’ve heard of” for a data center.
Springfield Memorial Hospital, the largest hospital in the county, utilizes just six backup generators for its main hospital in case of an outage. Those generators are necessary to power lifesaving medical equipment and technology in case of grid failure, while the hundreds of generators planned for the data center will be used to power racks of computer chips.
“For many states, there’s really no regulation on those generators largely because they are meant for emergency purposes,” Zhang said. “Which means they could deploy diesel generators without stringent emission controls.”
While there are some federal rules for emergency use of large-scale generators, there are no such rules for smaller-scale generators. Meanwhile, the Trump administration has repealed environmental regulations at a full sprint and, as has become common, faces lawsuits.
“Given the number of generators, even only (running) 15 hours per year, that’s still going to have the potential to cause a lot of impact,” Zhang said. His research “found that the typical emission factors from diesel backup generators are at the level of the most-polluted combustion turbines, which means they tend to be highly polluting.”
Electricity generated by combustion is responsible for more than 1,500 tons of pollutants and accounts for nearly 60% of emissions in Sangamon County, according to EPA emissions data from 2020.
CyrusOne, in a January letter to the county, wrote that the center will “include air pollution controls on emergency generators, secondary containment on fuel storage tanks,” but Zhang said exhaust stacks that are used for generators to vent the combusted diesel also have few regulations.
“There are really no regulations on the (exhaust) stacks,” Zhang said. “The reason for the absence of regulation is because they are they are meant for emergency purposes, but at the same time for the case we’re talking about, there’s a high probability they will be run when the grid is stressed, I presume.”
Zhang said emissions produced by diesel-powered generators can drift with the wind and, in general, “meteorological conditions can affect the emission impact a lot.”
County Board members will conduct a final vote during a March 23 meeting that begins at 6 p.m. at the BOS Center. The meeting was relocated from the County Board chambers to accommodate what is anticipated to be a large public turnout.
This article appears in March 19-25, 2026.
