The Jacksonville Journal-Courier and Capitol News Illinois published joint reporting that canvassed local mayors hosting data centers across the state. Some described the property tax revenue as transformative for towns that had been losing manufacturing for decades. Others described the millions of gallons of water consumed and the queue of large-load interconnect requests at ComEd as evidence that the deals are not worth what they cost.
The Data Center Coalition's 2023 study, cited in the reporting, claims data centers added 115,130 jobs across Illinois in 2022-2023 and contributed $19 million to state GDP. The numbers that did not get cited as prominently are the ComEd queue numbers: the territory has enough large-load energy projects in interconnect that, if approved, would more than double the entire ComEd electricity demand by 2040. The grid arithmetic is the part of the mayors' calculus that is shifting opinions.
An Illinois mayor evaluating a data center proposal is mostly evaluating property tax revenue against local infrastructure cost. A data center pays property tax to the host municipality and county. Most operational employees live within commuting distance, so income tax revenue stays in the region. Capex deployment ripples through local construction labor for the build years. On those metrics, the local case is straightforward for a town that has been losing population.
The statewide math runs the other direction. Electricity rate increases driven by data center load growth land on residential ratepayers across the entire ComEd territory, not just in the host town. Water consumption affects regional aquifer levels rather than just the host municipality. The transmission and distribution upgrades that data center loads require are funded through grid-wide ratepayer assessments. The mayor who approves a data center captures most of the upside locally. The downside is socialized across the state.
Cooling is where the local-statewide math gets quantitative. A data center running open-loop evaporative cooling on a municipal water connection draws against local water resources visible to the host town. The cooling water draw is the most measurable externality the mayor can point to when explaining the deal to constituents. When the audit gets imperfect, the politics get ugly fast.
A facility running closed-loop or dry cooling takes that externality off the table at the local level entirely. The local mayor has a cleaner political case to make. The deal feels less like a trade and more like a one-sided import of capital. Zero-water cooling pilots in Phoenix and Mt. Pleasant represent the architectural choice that improves the political math at every level of government simultaneously.
Cooling vendors selling into Illinois facilities should be paying close attention to which towns are quietly enthusiastic and which are quietly hostile. The split among mayors is a leading indicator of the policy environment over the next 24 months. Towns where the mayor is publicly defending the data center deal will continue to permit expansion. Towns where the mayor is hedging will not.
The vendor base also has an opportunity here. Most of the mayors quoted in the Capitol News Illinois reporting are not technical experts on cooling architecture. They evaluated the deals presented to them. If a vendor walks into a town with a pre-engineered closed-loop cooling architecture and the local political math built into the pitch, the mayor's case to constituents improves. That is a sales conversation cooling vendors should be having directly with municipalities, not just with operators. The town's permit decision is now upstream of the operator's selection decision, and the cooling vendor has the most relevant technical answer to the political question the town is being asked. Selling to the local government is the new go-to-market.