By Data Center Infrastructure News & Events · Thursday, October 1, 2026 · 5 min read

ComEd's Deposit and Credit Rules for Data Centers Are Becoming the Template Other Midwest Utilities Are Testing

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ComEd's Screening Cut Four of Eleven Large-Load Projects as Midwest Utilities Set Their Own Rules

ComEd's tightened grid-connection screening has allowed only four of eleven large-load projects evaluated to advance toward interconnection, Crain's Chicago Business reported on September 15, 2026. That filter, not the utility's deposit schedule, is the number a developer pricing Illinois risk should look at first. The Illinois Commerce Commission's March 20, 2026 order approving ComEd's security-deposit plan put the pipeline behind that screening at more than 75 projects seeking 28,000 megawatts, according to Capital News Illinois.

Six major data center customers have already posted $1 billion in letters of credit under ComEd's new security agreements, Crain's reported. The same report said ComEd is weighing "intermittent interruptions" in service during peak demand, or requiring data centers to bring their own generation, as conditions for projects that clear screening. Both the $1 billion figure and the four-of-eleven count come from that single Crain's report; the publication did not specify the exact window over which the eleven projects were evaluated, and no second outlet has independently reported either number.

What the Deposit Schedule Actually Costs

Behind that screening sits the deposit rule itself. Edison Electric Institute's September 11, 2026 tracker, independently corroborated by The Real Deal on March 20, 2026, describes ComEd's revised tariff charging a starting deposit of $1 million for projects between 50 and 200 megawatts, rising by $500,000 for every additional 100 megawatts. A developer proposing a 500-megawatt campus would owe roughly $2.5 million before interconnection work proceeds. The ICC called its own order an "important first step" and directed staff to open further proceedings on reliability and affordability risks the deposit rule does not yet address, Capital News Illinois reported.

The TSA Layer Sits Above the Deposits

ComEd had already moved on a separate front two months earlier. On January 6, 2026, the utility announced Transmission Security Agreements with eight large customers representing 6.5 gigawatts of forecasted load, according to a Business Wire release carrying CEO Gil Quiniones's name. ComEd's own release states that these agreements cap transmission charges borne by existing ratepayers at $2 billion over ten years, with a signed customer absorbing any shortfall between its projected and actual load dollar for dollar. That $2 billion figure and the shortfall mechanism come from ComEd's press release alone; no commission order or independent filing in the available record confirms the number.

Deposits recover stranded infrastructure cost if a project dies. TSAs recover transmission cost if a project under-delivers.

Other States Are Building Similar Structures — Not Copying Illinois

Wisconsin and Minnesota regulators approved comparable large-load tariffs within three weeks of each other this spring, though neither order references ComEd's structure in the material available. The Wisconsin Public Service Commission approved We Energies' "Very Large Customer" and "Bespoke Resources" tariffs on April 24, 2026, and the Minnesota Public Utilities Commission approved Xcel Energy's data center tariff on May 15, 2026, according to Climate Solutions Legal Digest. That publication is the only outlet in the available record reporting either approval; no docket number or second source has been located for either order.

South Dakota took a legislative route. CSG Midwest reported on May 22, 2026 that the state passed SB 135, the "Data Center Bill of Rights," requiring electricity providers to set separate terms for data center customers that guarantee full cost recovery. The Data Center Coalition told CSG Midwest it is open to large-load tariffs provided they apply consistently across all large industrial users — a condition operators are likely to raise wherever a similar structure is proposed.

Missouri Attaches a Dollar Figure, Not Always a Clear Baseline

Ameren Missouri's "Powering Missouri Growth Plan," which the company's June 26, 2026 disclosure describes as approved "in late 2025" without a more specific date or docket number, requires customers with 75 megawatts or more of peak demand to cover their share of grid enhancements. Rob Dixon, Ameren's vice president of regulatory affairs, said the commitments from new data center customers are projected to deliver $11 million annually in base rate savings for other customers — Ameren's own forward estimate, not an independently audited figure, the company disclosed on June 26, 2026.

Ameren's September 30, 2026 integrated resource plan, reported by Utility Dive, commits the utility to serving 2.8 gigawatts of large-load demand by 2030. Utility Dive's report describes that figure as nearly double the utility's prior 2025 expectation, but does not state what that earlier figure was, so the comparison cannot be checked against a baseline.

Ohio's Filings Are Still Pending

Duke Energy Ohio's proposed "Rate DC" and AES Ohio's data center tariff remain pending before Ohio regulators, according to EEI's September 2026 tracker, which does not detail the rate design or thresholds either filing proposes. Those decisions, whenever they land, will be the next test of how closely a new state follows the deposit-and-shortfall structure Illinois, Wisconsin and Minnesota have each built in their own form.

What none of the approved orders addresses, on the record available, is what happens when a developer walks away after posting a deposit but before construction starts. The ICC's March 20 order anticipated that gap only by directing staff to open further proceedings on reliability and affordability — it did not resolve the question, and the available filings do not show whether Wisconsin's or Minnesota's tariffs address forfeiture terms at all. That is the proceeding worth tracking next, not the deposit schedule itself.

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