How to Switch Electricity Suppliers in Illinois: A Step-by-Step Guide for Cannabis Businesses

Step 1: Confirm the account is eligible

Illinois opened its retail market under the Electric Service Customer Choice and Rate Relief Law of 1997, and all non-residential customers of ComEd and Ameren Illinois can buy supply from an Alternative Retail Electric Supplier certified by the Illinois Commerce Commission [il-plugin-illinois]. MidAmerican customers in the Quad Cities have the same right in law but little practical supplier interest [il-plugin-illinois]. Reliability, outage response, and delivery stay with the utility and stay regulated by the ICC [plugin-choice-basics].

The eligibility question that matters for a cannabis business is not the utility, it is the account. A dispensary in a strip center whose electricity is on the landlord's meter cannot switch; the landlord's account would have to switch. A craft grow in buildout does not have an account to switch until service is energized. Get the account into the licensee's name first.

Step 2: Pull twelve months of bills and interval data

From each bill, record the account number, meter number, delivery class, monthly kWh, monthly peak kW, and the supply and transmission charges. The utility bill page shows where each line sits. For accounts above ComEd's Small Load class or Ameren's DS-2 class, ask the utility for interval data; suppliers pricing a large account will want it, and ComEd's tariff provides for a designated supplier to receive the customer's meter and billing data once enrolled [comed-rate-rds].

Step 3: Find your benchmark

For small accounts, the benchmark is the utility's Price to Compare, defined as the electric supply charge plus the transmission services charge [plugin-ptc-comed]. ComEd's summer 2026 figure is 10.399 cents per kWh, combining 8.677 cents of supply and 1.722 cents of transmission, effective June 1 through September 30, 2026 [plugin-ptc-comed]. Ameren's summer 2026 Price to Compare is 11.326 cents per kWh for the first 800 kWh, combining 8.2 cents of supply and 2.765 cents of transmission [plugin-ptc-ameren]. Both are residential figures. A nonresidential account's supply charge is class-specific, so read it off the bill rather than the website, and remember that utility default customers are also subject to the Purchased Electricity Adjustment, a monthly credit or charge that a supplier customer avoids [plugin-ptc-comed].

For larger accounts there is no fixed benchmark. Ameren's DS-3 and DS-4 customers who take supply from the utility are served under Rider HSS, an hourly price [ameren-ds3-tariff]. ComEd's Rate RDS is written so that larger nonresidential customers arrange supply through a retail electric supplier, Rider PPO, or self-management [comed-rate-rds]. The benchmark for those accounts is the trailing twelve months of actual supply cost.

Step 4: Verify the supplier is certified

The ICC certifies suppliers under 220 ILCS 5/16-115 and 83 Ill. Adm. Code Part 451 and publishes the list of certified ARES through its entity database, with annual compliance filings due each April 30 [icc-ares-certification]. Check the name on the offer against that list. A supplier that is not on it cannot serve you regardless of what the offer says, and the law prohibits switching a customer without authorization [plugin-consumer-protections].

Step 5: Request and compare offers on the same basis

Ask every supplier for the same term length, the same product type, the same start month, and the same treatment of capacity, transmission, and losses. Illinois offers tend to differ on whether PJM or MISO capacity is bundled into a fixed price or passed through at cost, and that single difference can be worth more than the headline rate. Use the contract comparison worksheet to line them up. Suppliers must make marketing claims about price and terms that adequately disclose the prices, terms, and conditions [plugin-consumer-protections], but disclosure is not the same as comparability; that part is on you.

Step 6: Sign and choose a billing option

Before signing, read the term, the renewal clause, the notice window, and the termination language. The contract terms page covers the traps. Illinois law since January 1, 2020 lets residential and small commercial customers terminate a supplier contract at any time without termination fees [plugin-choice-basics], and suppliers cannot apply early termination penalties to those customers [plugin-faq]. A cultivation or extraction account is not small commercial, so its termination terms are whatever the contract says.

Then pick how you want to be billed. Plug In Illinois describes three options: one bill from the utility with the supplier's charge on it, a single bill from the supplier, or separate bills from each [plugin-faq]. Ameren labels them dual billing, single bill option, and utility consolidated billing [ameren-business-choice]. ComEd's tariff provides a Single Bill Option under Rider SBO with a small credit to the customer when the supplier bills delivery [comed-rate-rds].

Step 7: Let the supplier submit the enrollment

Once you have agreed, the supplier submits an electronic enrollment transaction to the utility [ameren-business-choice] [plugin-switching-process]. The utility then contacts you by mail to confirm the selection [plugin-switching-process]. At Ameren you have 10 calendar days from the date Ameren processes the enrollment to contact Ameren and cancel [ameren-business-choice]. The ICC's consumer protection page states the same 10-day rescission right for residential and small commercial customers in both territories [plugin-consumer-protections]. Larger commercial accounts should treat the contract signature as the point of no return.

Step 8: Confirm the switch at the next meter read

The effective date of the change depends on your next meter read [plugin-switching-process]. Nobody visits the site and there is no interruption [plugin-switching-process]. On the first bill after the switch, check three things: the supplier's charge appears, the utility's supply and transmission lines are gone (Ameren notes both are replaced by the supplier's charges [plugin-ptc-ameren]), and the delivery charges are unchanged [plugin-choice-basics]. If the delivery lines moved, something else changed, most likely a delivery class reassignment, and that needs its own look.

Step 9: Calendar the contract end date

Put the end date and the notice window on the same calendar as license renewals. The supplier contract governs what happens at expiry; many renew month to month or roll to a variable price if you do nothing. If the account instead returns to utility supply, the utility charges no fee, but Plug In Illinois warns you might have to stay on utility supply for 12 months before selecting a supplier again [plugin-switching-process]. For a large grow that would mean a year on Ameren's hourly Rider HSS or ComEd's default arrangement. Re-bid three to four months before expiry so the next contract starts at the meter read the old one ends on.

Mistakes Illinois operators make

• Comparing a supplier offer to the residential Price to Compare. A DS-3 or Medium Load account is not on that price. Compare against the bill.
• Assuming the no-fee termination right applies. It covers residential and small commercial customers. Grows and labs are neither.
• Letting a large account lapse to default. The 12-month stay-on-utility warning applies to returning customers, and hourly default is the worst place to sit for a year while you shop.
• Forgetting the ISO. A supplier serving both your ComEd and Ameren accounts is pricing two markets. Check that the capacity language matches each one.
• Switching a month before a June reassignment. Ameren moves accounts between DS-2, DS-3, and DS-4 with the June billing period; ask the supplier to price the class you will be in, not the one you were in.

The ComEd page and the Ameren page go deeper on each utility's billing mechanics, and the Illinois rate page has the current benchmarks in one table. Illinois switching rules sit in ICC rules and utility tariffs that change; confirm current terms with the ICC or your advisor before signing.

Document retention for ICC compliance

Keep enrollment confirmations, supplier contracts, and the first post-switch bill showing delivery unchanged and supply moved to ARES [plugin-switching-process]. Archive witness test results and rate class assignment for lender diligence [icc-ares-certification]. When returning to utility supply, note the Plug In Illinois warning that you may have to stay twelve months before choosing a supplier again [plugin-switching-process].

Block-and-index for flat cultivation load

Illinois cultivators with predictable lighting blocks sometimes use block-and-index contracts to hedge a portion of load while leaving shoulder hours exposed [il-plugin-illinois]. Compare fixed vs index vs block-and-index with explicit PJM or MISO capacity language before signing [ameren-rider-hss].

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-ares-certification]. Facility managers should reconcile billing demand to interval peaks monthly and escalate discrepancies before paying disputed invoices [plugin-choice-basics]. Corporate finance should map utility COGS to cultivation, processing, or retail cost centers consistently across sites [plugin-switching-process]. Legal should keep meter assignment language in leases aligned with the license holder on the utility account [plugin-consumer-protections]. Confirm current rules with the regulator or your advisor before signing supply contracts [il-plugin-illinois].

Documentation for audits and lenders

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-ares-certification]. Facility managers should reconcile billing demand to interval peaks monthly and escalate discrepancies before paying disputed invoices [plugin-choice-basics]. Corporate finance should map utility COGS to cultivation, processing, or retail cost centers consistently across sites [plugin-switching-process]. Legal should keep meter assignment language in leases aligned with the license holder on the utility account [plugin-consumer-protections]. Confirm current rules with the regulator or your advisor before signing supply contracts [il-plugin-illinois].