Illinois Commercial Electricity Rates for Cannabis Facilities: ComEd and Ameren Classes, Benchmarks, and Bill Drivers

Illinois vs. the U.S. average

Sector	Illinois, June 2026	U.S. average, June 2026	Illinois vs. U.S.
Commercial	14.53 cents/kWh	14.19 cents/kWh	+0.34 cents, about 2 percent higher
Industrial	10.65 cents/kWh	not in state file

Source: EIA Electric Power Monthly, Table 5.6.A [eia-epm-5-6-a].

The EIA number is average revenue per kWh across every commercial customer, so it blends delivery and supply, small stores and large plants, PJM and MISO. It is a sanity check, not a tariff. For a cannabis operator the useful reading is the 3.88 cent gap between commercial and industrial. Most of that gap is structure: larger accounts spread fixed delivery charges over more kWh, take service at higher voltage, and get supply priced against a flatter load. A grow that runs lights on a fixed schedule with a managed peak can price closer to the industrial line than the commercial one.

ComEd delivery classes and how demand is billed

ComEd sorts nonresidential accounts into delivery classes by demand or, for the smallest, by monthly kWh [comed-delivery-charges-guide]. The table below uses the charges ComEd published as effective with the September 2025 bill, which are the most recent full set opened for this page. They change on the CEJA multi-year rate plan schedule, so use them for structure and check the current sheet for a number.

ComEd delivery class	Threshold	Customer charge (monthly)	Distribution facilities charge	Basis
Watt-Hour	Under 2,000 kWh a month	see tariff	per kWh	Energy
Small Load	0 to 100 kW	$23.69	$0.03309 per kWh	Energy
Medium Load	101 to 400 kW	$23.32	$14.59 per kW secondary; $6.50 per kW primary	Peak demand
Large Load	401 to 1,000 kW	$34.61	$14.95 per kW secondary; $8.51 per kW primary	Peak demand
Very Large Load	1,001 to 10,000 kW	$170.42	$14.60 per kW secondary; $11.54 per kW primary	Peak demand
Extra Large Load	10,001 kW and up	$1,002.90	$13.45 per kW secondary; $11.01 per kW primary	Peak demand

Source: ComEd guide to billed delivery service charges, September 2025 [comed-delivery-charges-guide]. All classes also pay a standard metering charge and an IEDT charge of about $0.00125 per kWh [comed-delivery-charges-guide]. Primary-voltage customers pay a small primary voltage transformer charge per kW when ComEd owns the transformer [comed-delivery-charges-guide].

The pattern to notice: the per-kW rate barely moves between Medium and Extra Large Load at secondary voltage, but the primary-voltage rate is much lower in the mid classes. For a grow in Medium or Large Load, taking primary service and owning the transformer roughly halves the per-kW distribution line. The demand charges page walks through how a single half-hour sets that line for the month.

Ameren Illinois delivery classes and how demand is billed

Ameren class	Threshold	Distribution delivery basis	Utility default supply
DS-2 Small General	Maximum monthly demand under 150 kW; without a demand meter, assumed under 150 kW while use stays under 1,200 kWh per day [ameren-ds2-tariff]	Per kWh on all usage [ameren-ds2-tariff]	Rider BGS fixed price, or RTP [ameren-ds2-tariff]
DS-3 General	150 kW up to but not including 1,000 kW [ameren-ds3-tariff]	Per kW of billing demand until the January 2027 billing period, then per kVA of apparent demand with a power factor penalty [ameren-ds3-tariff]	Rider HSS hourly [ameren-ds3-tariff]
DS-4 Large General	1,000 kW and up in two or more months of the prior calendar year [ameren-ds3-tariff]	Per kW (see DS-4 tariff)	Rider HSS hourly [ameren-business-choice]

Ameren's billing demand rule for DS-3 is the higher of the maximum on-peak demand in the billing period or 50 percent of the maximum off-peak demand [ameren-ds3-tariff]. Class reassignment happens with the June billing period, based on demand in two or more of the prior calendar year's twelve billing periods, and a reassigned customer stays in the new class for at least twelve billing periods [ameren-ds2-tariff] [ameren-ds3-tariff]. Ameren also bills a per-kW transformation charge when it owns the transformer, and from January 1, 2026 new company-owned transformation is available only through Rider EFC [ameren-ds3-tariff]. Per-kW dollar figures for DS-3 and DS-4 sit in the Rate PBR-R appendix and are not reproduced here because the current appendix sheet was not opened for this page.

Default supply benchmarks

Utility	Benchmark	Summer 2026 figure	Components	Applies to
ComEd	Price to Compare, June 1 through September 30, 2026	10.399 cents/kWh	8.677 supply + 1.722 transmission [plugin-ptc-comed]	Residential; nonresidential supply is class-specific
Ameren Illinois	Price to Compare, June 1 through September 30, 2026	11.326 cents/kWh on the first 800 kWh	8.2 supply + 2.765 transmission; includes a 0.308 cent supply cost adjustment [plugin-ptc-ameren]	Residential; DS-2 business supply under Rider BGS
Ameren DS-3 and DS-4	Rider HSS	Hourly	MISO day-ahead LMP for the delivery point, real-time settlement of deviations, plus a capacity charge per kW of planning-load contribution [ameren-rider-hss]	Customers 150 kW and up taking utility supply

Utility default customers are also subject to the Purchased Electricity Adjustment, the monthly difference between Price to Compare revenue and actual supply cost, which supplier customers avoid [plugin-ptc-comed]. Ameren's Price to Compare excludes its PEA as well [plugin-ptc-ameren].

ISO and capacity context

ComEd is in PJM and Ameren Illinois is in MISO [il-plugin-illinois]. For a supply contract, that decides how the capacity component is calculated. In MISO, Ameren's hourly rider assigns each customer a planning-load contribution, a kW figure representing its share of the forecast system peak, and bills capacity against it for each planning season starting June 1 [ameren-rider-hss]. Suppliers serving ComEd load carry a PJM capacity obligation based on the customer's peak-load contribution in the same way. Either way, the customer's demand during a handful of summer peak hours sets a cost that lasts a year. The rate classes page explains why the delivery class and the capacity tag are two different things that both come from peak demand.

Seasonality

Illinois averages 889 cooling degree days against 6,105 heating degree days, with summer dew points in the 60s and 70s [noaa-cag-illinois]. Electric load for a sealed grow peaks in the humid months, and so do the wholesale markets; Ameren identifies 5 a.m. to 9 p.m. daily and June through September as its generally highest-priced hours [ameren-business-choice]. The utilities' summer Price to Compare periods run June through September [plugin-ptc-comed] [plugin-ptc-ameren]. A grow in Illinois should expect July and August to carry the highest per-kW delivery bills and the highest supply exposure in the same month.

How to read an Illinois commercial bill

1. Find the delivery class on the bill and confirm it matches the table above for your peak kW.
2. Separate delivery from supply. Delivery is set by the ICC and changes on the CEJA multi-year plan schedule in Dockets 23-0055 and 23-0082, whether or not you have a supplier [icc-ceja]. Supply is what a contract controls.
3. Divide the supply and transmission dollars by kWh to get your actual benchmark in cents per kWh. That is the number to compare against supplier offers, not the residential Price to Compare.
4. For demand-billed classes, divide the distribution facilities or distribution delivery dollars by the billed kW and compare the result to the tariff rate. A mismatch usually means a voltage or transformer charge you were not expecting.
5. Check whether the account is near a class threshold: 100 kW or 400 kW at ComEd, 150 kW or 1,000 kW at Ameren. Within 10 percent of a line, peak management can change the class.

The ComEd utility page and the Ameren Illinois utility page go into each utility's metering, interconnection, and billing options. The demand charge estimator and the state rate comparison turn the numbers here into an estimate for a specific facility. Tariff figures on this page were verified on 2026-09-11 and change on ICC-approved schedules; check the current sheet before quoting one.

Procurement checklist before an ARES RFP

1. Confirm ComEd vs. Ameren territory and delivery class on each bill [il-plugin-illinois].
2. Export twelve months of interval data for any account above Small Load or DS-2 [ameren-ds3-tariff] [comed-delivery-charges-guide].
3. Separate delivery from supply; delivery changes on ICC schedules whether you shop or not [icc-ceja].
4. Request three ARES quotes with identical capacity and transmission pass-through assumptions [il-plugin-illinois].
5. Calendar June 1 PTC resets and Ameren June class reassignment before signing start dates [ameren-ds2-tariff] [plugin-ptc-comed].

Use the state commercial rate comparison tool to sanity-check Illinois against neighboring PJM states [eia-epm-5-6-a].