Illinois · Permitting
Illinois is the first large data center state to pull its own sales-tax exemption mid-cycle. Pair that with the POWER Act (50 MW+), IEPA's five-year nonattainment aggregation window, and the Joliet 795-acre approval, and the underwriting model that worked in February no longer clears. This page is maintained continuously against the public record.
Live · IEPA · ICC · DCEO · municipal ordinances
Last verified
5h ago
cadence · IEPA permits + ICC dockets + IL GA bills
Tax incentive suspension
70d left
Jul 1, 2026
Docket corpus
LLM-maintained
updates when filings land
What is moving · as of April 22, 2026
Upcoming
May 2026
POWER Act (SB 4016) committee hearings
Targets hyperscale facilities above 50 MW peak demand. Requires self-funded new renewable generation, water-usage disclosure, and expanded permitting transparency. Active in both chambers.
Upcoming
July 1, 2026
Tax incentive suspension effective
Governor Pritzker's two-year suspension of state data center sales-tax incentives for new developments. Projects already certified continue; new applications frozen.
Upcoming
Rolling 2022-2026
Nonattainment aggregation window
IEPA aggregates net NOx/VOC increases from the project year plus the four prior calendar years. A 2026 build carries 2022-2025 regional emissions as context for PSD review.
Upcoming
2027 session
Joliet / Will County follow-on ordinances
Joliet's 795-acre AI campus (approved 8-1 on Mar 20, 2026) has triggered neighboring municipalities to draft catch-up ordinances. Will, Kane, and McHenry county ordinance drafts expected.
Regulatory surface
Illinois straddles PJM (ComEd territory) and MISO (Ameren). Interconnection math, curtailment exposure, and queue timelines diverge across the state line at the Indiana and Missouri border. Add IEPA nonattainment aggregation and the ICC cost-allocation docket, and underwriting gets site-specific fast.
IEPA
Air permits, nonattainment aggregation, Title V
35 Ill. Adm. Code 203 · Chicago-Naperville-Elgin O3 aggregation
ICC
Utility tariff, large-load cost allocation
ICC docket · ComEd / Ameren large-load cost recovery
DCEO
State tax incentive administration (suspended Jul 1)
35 ILCS 105/3-5(49) · data center exemption
PJM · MISO
Interconnection queue split by service territory
PJM (ComEd) · MISO Zone 4 (Ameren)
Counties · municipalities
Zoning, special-use permits, incentive negotiations
Joliet (Will Co), Aurora (Kane Co), DeKalb, Elk Grove
Live filings
Cliff ingests these end-to-end, maps parties and deadlines, and extracts structured outcomes. Full party-by-party in the docket viewer.
IL SB 4016 · HB 5513
The POWER Act
Targets hyperscale data centers with peak demand above 50 MW. Requires operators to fund incremental renewable generation, disclose water usage, and submit to expanded permitting transparency. Active in both chambers; sponsor coalition includes IL environmental justice caucus.
Active · committee
source →Executive · Pritzker
Two-year tax-incentive suspension
Announced April 2026. Suspends the Illinois data center sales-tax exemption for new applications effective July 1, 2026. Grandfathers currently certified projects. NRDC tracking; DCEO guidance document pending.
Executive · effective Jul 1, 2026
source →Joliet · AI campus
795-acre approval (Mar 20, 2026)
Joliet City Council approved Illinois' largest data center campus 8-1. Estimated $2.1B in tax revenue over 30 years, 10,000 construction jobs. Template for Will County and adjacent municipalities. Trinity published a public explainer on this submission.
Approved
source →Backup generation · air
The Illinois kicker is nonattainment aggregation: a 2026 project in Chicagoland carries four prior calendar years of regional NOx/VOC emissions context into its PSD review. Same rule that rewrote Trinity’s Joliet advisory.
Model your site on the de-rate calculator.
IEPA permit hour caps vary with location. Chicago-Naperville-Elgin ozone nonattainment counties carry tighter aggregate caps and trigger nonattainment-aggregation review across the project year + four prior calendar years.
IEPA tracks the federal RICE NESHAP definition. No Illinois analog to VA APG-578 exists. PJM and MISO-initiated curtailment events do not count as 'emergency' runtime.
Typical: 5 mo. Title V: 10 mo. PSD: 16 mo.
Chicago-Naperville-Elgin (9-county area) · Metro-East St. Louis (3-county IL portion)
Source: IEPA Bureau of Air · 35 Ill. Adm. Code 203. Last verified 2026-04-22; next refresh due 2026-07-22. Not yet in stateAirPermits.ts; hardcoded here pending addition on first verified lead.
Why this page exists
Trinity Consultants is the rare permitting firm that publishes an Illinois explainer (strategic permitting for IL data center expansions). It focuses narrowly on air. It cannot, by contract, name the Joliet applicant or cover the ICC cost-allocation docket, the POWER Act, the Pritzker tax freeze, or the nonattainment-aggregation window at the same time.
Cliff does all of those together and keeps them current. Platform versus retained advisor. Publishable versus conflicted.
Illinois diagnostic
One parcel, a concept MW, and your service territory (ComEd or Ameren). We return a cited readout of your exposure across IEPA nonattainment aggregation, the POWER Act, the tax suspension, and ICC cost allocation within one week.