ComEd for Cannabis Facilities: Delivery Classes, Demand Charges, Default Supply, and Supplier Billing

Service area and grid operator

ComEd, Commonwealth Edison, is the largest Illinois utility and serves Chicago and northern Illinois inside the PJM Interconnection [il-plugin-illinois]. For a cannabis operator that means two things. Delivery, metering, and outages are ComEd's job and are regulated by the Illinois Commerce Commission. Supply for a nonresidential account is priced against PJM energy and capacity, whether the utility or a supplier arranges it.

ComEd is on a multi-year rate plan under the Climate and Equitable Jobs Act, with delivery charges moving on a schedule set in ICC Docket 23-0055 [icc-ceja]. Every dollar figure on this page comes from ComEd's guide to billed delivery service charges effective with the September 2025 bill [comed-delivery-charges-guide]; treat them as the structure of the bill and check the current informational sheet before quoting one.

Delivery classes and what puts you in one

Rate RDS identifies fifteen delivery classes, of which six matter to a cannabis business: Watt-Hour, Small Load, Medium Load, Large Load, Very Large Load, and Extra Large Load [comed-rate-rds]. The thresholds:

Delivery class	Threshold	Typical cannabis account
Watt-Hour	Under 2,000 kWh a month [comed-delivery-charges-guide]	Office, small kiosk
Small Load	0 to 100 kW [comed-delivery-charges-guide]	Most dispensaries, a small lab
Medium Load	101 to 400 kW [comed-delivery-charges-guide]	Craft grow, larger lab, flagship store
Large Load	401 to 1,000 kW [comed-delivery-charges-guide]	Larger craft grow, small cultivation center
Very Large Load	1,001 to 10,000 kW [comed-delivery-charges-guide]	Cultivation center
Extra Large Load	10,001 kW and up [comed-delivery-charges-guide]	Not typical in cannabis

Placement is based on measured demand, which ComEd meters in half-hour intervals; Rate RDS refers throughout to 30-minute demands, including in its availability language for customers that do not exceed 100 kW [comed-rate-rds]. A facility that is 95 kW for 29 days and 110 kW for one afternoon is a Medium Load customer. The interval data page covers how to pull those half-hours from ComEd's smart meters and find the ones that matter.

Demand charge structure

ComEd's delivery bill for a demand-metered class has four main lines: a customer charge, a standard metering service charge, the distribution facilities charge, and the IEDT charge per kWh [comed-delivery-charges-guide]. The distribution facilities charge is where the class shows up:

Class	Customer charge	Distribution facilities charge, secondary voltage	Distribution facilities charge, primary voltage
Small Load	$23.69	$0.03309 per kWh	not applicable
Medium Load	$23.32	$14.59 per kW	$6.50 per kW
Large Load	$34.61	$14.95 per kW	$8.51 per kW
Very Large Load	$170.42	$14.60 per kW	$11.54 per kW
Extra Large Load	$1,002.90	$13.45 per kW	$11.01 per kW

Source: ComEd, charges beginning with the September 2025 bill [comed-delivery-charges-guide]. Primary-voltage customers with a ComEd-owned transformer also pay a primary voltage transformer charge of $0.40 to $0.54 per kW depending on class [comed-delivery-charges-guide].

Two things stand out for a grow. First, at secondary voltage the per-kW rate is nearly the same from Medium through Very Large Load, so crossing a class line changes the customer charge more than the per-kW rate. Second, primary voltage in Medium Load is less than half the secondary rate. For an assumed 300 kW grow, that is $14.59 × 300 = $4,377 a month at secondary against $6.50 × 300 = $1,950 at primary plus a $0.40 × 300 = $120 transformer charge, a difference of about $27,700 a year for the life of the facility [comed-delivery-charges-guide]. The capital cost of taking primary service and the tariff terms for it are a buildout decision; see demand charges explained for how the peak is measured.

Default supply and the Price to Compare

For residential and small customers, ComEd's default is Basic Electric Service, and the ICC publishes the Price to Compare: 10.399 cents per kWh for June 1 through September 30, 2026, made up of 8.677 cents supply and 1.722 cents transmission [plugin-ptc-comed]. Default customers are also subject to the Purchased Electricity Adjustment, the monthly reconciliation of Price to Compare revenue against actual supply cost, and a customer who switches to a supplier is not [plugin-ptc-comed].

For larger nonresidential accounts, ComEd's Rate RDS is the delivery tariff, and its availability section makes it unavailable to a brand-new applicant that would be a residential, small lighting, Watt-Hour, or Small Load customer until that customer has first taken bundled service; larger applicants take delivery under RDS with supply from a retail electric supplier under Rate RESS, from ComEd under Rider PPO, or as a Customer Self-Manager [comed-rate-rds]. The Price to Compare is therefore not the benchmark for a Medium Load grow. The benchmark is the trailing cost on the bill.

Metering and interconnection notes for a grow

• AMI is standard. Rate RDS provides for AMI metering and for nonstandard metering charges where a customer refuses AMI [comed-rate-rds]. A grow should keep AMI; interval data is the only way to manage a per-kW charge.
• Voltage and transformer ownership are set at service design. The primary-versus-secondary difference above is the single largest delivery decision a new facility makes.
• On-site generation. ComEd's delivery charges include a distributed generation rebate adjustment factor, which appears in the buildup of every class's charges [comed-delivery-charges-guide]. A grow considering solar under the Illinois Shines Large DG track, 25 kW to 2 MW with 15-year REC contracts, should model the effect on peak demand separately from energy, because a per-kW charge does not fall unless the array is producing during the facility's peak half-hour [illinois-shines]. See on-site solar and storage.
• Demand response. A PJM-territory grow with controllable lighting and HVAC can enroll in demand response through a curtailment service provider, which pays for the same peak management that lowers the distribution facilities charge.

Efficiency programs run by ComEd

ComEd's business energy efficiency program offers prescriptive and custom incentives funded under the state's efficiency portfolio standard, and its standard incentive list includes LED grow lights meeting DLC horticultural listing and efficacy requirements [comed-ee-business]. Custom incentives cover measures outside the standard list, which is where dehumidification and chiller upgrades usually fall. Pre-approval before purchase is typical for custom projects; confirm current requirements with the program.

How a supplier contract works with ComEd billing

When a customer designates a supplier, the supplier takes service under Rate RESS, arranges transmission and ancillary services on the customer's behalf, and receives the customer's meter and billing data [comed-rate-rds]. ComEd or PJM may bill the supplier for certain delivery components, but the customer remains responsible if the supplier does not pay [comed-rate-rds]. Billing then works one of three ways:

1. Utility bill with supplier charge. ComEd keeps sending one bill; the supplier's supply charge replaces ComEd's supply and transmission lines. The most common arrangement.
2. Single Bill Option under Rider SBO. The supplier bills ComEd's delivery service charges together with its own supply, and ComEd credits the customer for each bill it electronically submits to the supplier, with the credit amount set in Informational Sheet No. 34; the credit is not available in months with a past-due bundled service balance [comed-rate-rds].
3. Dual billing. ComEd bills delivery, the supplier bills supply.

The switch itself is submitted by the supplier and confirmed by ComEd by mail, and takes effect at the next meter read [plugin-switching-process]. Plug In Illinois warns that a customer returning to utility supply might have to stay there for 12 months before choosing a supplier again [plugin-switching-process]; for a Medium Load grow that means a year without a fixed price, so do not let a contract lapse. The full procedure is on the Illinois switching guide, and the Ameren Illinois page covers the other half of the state for operators with sites in both.

CEJA delivery resets and procurement timing

ComEd delivery charges change on the CEJA multi-year rate plan schedule the ICC approves in Dockets 23-0055 and 23-0082 [icc-ceja]. A fixed ARES contract signed in March does not freeze delivery lines that reset in September. Reconcile billed kW to interval peaks after every rate-plan order [comed-delivery-charges-guide]. June 1 Price to Compare resets affect small accounts; Medium Load grows compare against trailing bill supply, not the residential website figure [plugin-ptc-comed].

Social equity craft grows and service sizing

All 87 craft grower licenses issued through FY2025 went to social equity applicants, and many are still in buildout [il-annual-cannabis-report-2025]. Oversizing initial service creates a demand baseline before first harvest. Model energization load against the licensed footprint, not a five-year expansion plan, when requesting ComEd Medium or Large Load service [il-annual-cannabis-report-2025].

Quarterly bill review cadence

Maintain a utility folder with the current tariff PDF, last twelve months of bills, interval exports where available, supplier contracts, and witness test reports [il-plugin-illinois]. Update the folder after every rate case order and every benchmark reset published by the regulator [icc-ceja]. Facility managers should reconcile billing demand to interval peaks monthly and escalate discrepancies before paying disputed invoices [comed-ee-business]. Corporate finance should map utility COGS to cultivation, processing, or retail cost centers consistently across sites [illinois-shines]. Legal should keep meter assignment language in leases aligned with the license holder on the utility account [comed-delivery-charges-guide]. Confirm current rules with the regulator or your advisor before signing supply contracts [il-plugin-illinois].