Illinois commercial electricity: PJM and MISO

Which Illinois business addresses can actually shop for supply

Illinois certifies retail suppliers, but choice is a property of the utility territory, and the state's territories do not behave alike. The Illinois Power Agency states plainly that customers of Ameren Illinois, ComEd and MidAmerican Energy may choose who provides their electricity supply, and that the same options are not available to customers of municipal electric utilities, rural electric cooperatives, and Mt. Carmel Public Utility. The Illinois Commerce Commission regulates four investor-owned electric distribution utilities — Ameren Illinois, ComEd, MidAmerican and Mt. Carmel — and, of the four, only the first three run an active competitive market. Mt. Carmel is the edge case: its customers hold the right to choose, but no supplier has registered to serve them, so the right exists on paper and not in practice. Cooperatives and municipal systems may elect to enter the competitive market but are not required to, which means a site inside one of those systems has no competitive supply to compare unless the system itself offers it.

• Customers of Ameren Illinois, ComEd and MidAmerican may choose their supply.
• Choice is not available to municipal systems, rural cooperatives, or Mt. Carmel.
• The ICC regulates four investor-owned electric distribution utilities.
• Mt. Carmel customers hold the right to choose, but no supplier has registered.
• Co-ops and municipal systems may offer choice but are not required to.

Supply, transmission and delivery: what the Price to Compare covers

Illinois splits an electric bill into three parts — supply, transmission and distribution — and the state's shopping benchmark, the Price to Compare, is not a supply-only number. It is defined as the electric supply charge plus the transmission service charge, so it already carries a transmission component that a supply-only offer may or may not include. On a switch, the supplier's charges replace the utility's supply and transmission lines together; the delivery section stays with the utility and is set by tariff whoever supplies the commodity. The practical consequence is that two Illinois offers cannot be lined up against the Price to Compare until each states whether it covers transmission, because a supplier quoting supply alone is not quoting the same thing the utility does. The utility benchmark also carries a true-up: ComEd and Ameren Illinois each apply a Purchased Electricity Adjustment that reconciles the cost of procured power with what customers paid, and each states that a customer is not subject to that adjustment after switching to a supplier. Ameren also folds a largely fixed Supply Cost Adjustment into its supply charge, which its Price to Compare includes.

• Illinois bills separate supply, transmission and distribution.
• The Price to Compare is supply plus transmission, not supply alone.
• A supplier's charges replace the utility's supply and transmission lines.
• Delivery stays with the utility and is set by tariff.
• The Purchased Electricity Adjustment does not follow a customer who switches.
• Ameren's Supply Cost Adjustment sits inside its Price to Compare.

When a business does not shop, an agency buys the power

Utility supply in Illinois is not something the utility decides. For customers who have not chosen a supplier, the Illinois Power Agency develops an annual Electricity Procurement Plan and procures the electricity, and the Illinois Commerce Commission approves that plan; the utility then buys under contracts of various durations and passes the cost through without a mark-up. The agency describes the timing as roughly twice a year, a spring and an autumn purchase, unless the Commission approves a different schedule. That procurement cycle is why the utility's supply price moves on its own calendar: it resets when procurement results reset, not when a customer's usage changes. It also sets who the default covers. The agency builds the portfolio for residential and small commercial customers of the utilities that have not switched, so the largest accounts — which typically have — sit outside it and buy under their own contracts.

• The Illinois Power Agency develops the annual procurement plan.
• The ICC approves the plan and the utility buys under it.
• Purchases run roughly twice a year, in spring and autumn.
• Utilities pass the cost through with no mark-up.
• The default covers non-switching residential and small commercial load.

PJM in the north, MISO in the centre and south

Illinois is the clearest state in which one jurisdiction spans two wholesale markets. ComEd territory in the north, including Chicago, is inside PJM; Ameren Illinois territory in the centre and south is inside MISO. The two systems buy capacity in different ways — PJM through its Reliability Pricing Model, MISO through its own resource-adequacy framework — and the Commission has studied the MISO side in its own MISO Zone 4 resource-adequacy work. For a buyer the point is not which market is cheaper on a given day but that capacity is a supply-side cost settled per market and per zone, so two Illinois sites with identical annual consumption can carry different capacity exposure inside an otherwise similar supply price. It is one reason a statewide blanket quote is a weaker instrument than a quote built per utility territory and reconciled against each site's own class.

• ComEd territory is in PJM; Ameren Illinois territory is in MISO.
• Capacity is bought differently in each market.
• ComEd's and Ameren's capacity exposure are not interchangeable.
• The ICC has studied MISO Zone 4 resource adequacy.
• Capacity lands inside the supply price, not the delivery tariff.

Delivery classes turn on metered demand, not annual volume

In Ameren Illinois territory the delivery class a site sits in is decided by metered demand, and the thresholds are published in the company's filed tariff: Rate DS-2 for non-residential service below 150 kilowatts, Rate DS-3 for demand at or above 150 kW but below 1,000 kW, and Rate DS-4 from 1,000 kW. Ameren defines demand as the highest average load in a fifteen-minute interval, and the tariff reassigns a customer who drifts across a line: below 150 kW in at least two of the prior twelve billing periods moves a site down to DS-2, at or above 1,000 kW in two or more periods moves it up to DS-4, each effective with the next June billing period, and a reassigned customer cannot return to DS-3 for a minimum of twelve billing periods. None of this changes when a business switches supplier. Delivery is the utility's service, the class is set by the meter's demand history, and the supply switch sits above it.

• Ameren's classes run DS-2 below 150 kW, DS-3 to 1,000 kW, DS-4 above.
• Demand is the highest fifteen-minute interval.
• Reassignment is decided over the prior twelve billing periods.
• Reassignment takes effect with the next June billing period.
• A supply switch does not change the delivery class.

Municipal aggregation reaches small businesses up to a usage line

Illinois authorises government aggregation under Section 1-92 of the Illinois Power Agency Act, and the programme is a supply purchase made on behalf of a group — not a change to delivery. Only communities in the Ameren Illinois and ComEd territories are pursuing it, and the statute does not reach customers served by an electric cooperative or by a municipal system that owns its own distribution. A programme takes one of two forms: an opt-out programme, which needs a referendum and enrols eligible customers unless they decline, and an opt-in programme, which enrols only those who ask. The eligible classes are residential and small commercial customers with total annual consumption of 15,000 kilowatt-hours or less, so the aggregation pool has a hard ceiling and a business above it is outside the programme by definition. Terms run from one to three years, and a customer already under a supplier contract or on the utility's real-time pricing option is generally not swept in.

• Government aggregation is authorised by Section 1-92 of the IPA Act.
• Only Ameren Illinois and ComEd territories host programmes.
• Co-op and municipal-system customers are outside the statute.
• Eligible load is residential and small commercial at or below 15,000 kWh a year.
• Programmes run one to three years and take opt-out or opt-in form.
• A business already under contract is generally not enrolled.

The no-fee exit, and who actually holds it

Illinois attaches a termination right to the small end of the commercial market. Since 1 January 2020, residential and small commercial retail customers may terminate a supplier contract at any time without termination fees or penalties, and the ICC's consumer site states the same rule in the aggregation context: suppliers are prohibited from applying early termination fees or penalties to residential and small commercial customers who switch or return to the utility. That same source is careful about who the protection is for, and it turns on the class. A business inside the small commercial definition can treat the exit as unpenalised; a larger account cannot assume it, and has only the termination clause it signed. The state does regulate the seller, though: a company selling retail electric service in Illinois needs ICC certification, and that covers not only the supplier but the agents, brokers and consultants who procure on a customer's behalf.

• Since 1 January 2020 small commercial customers can exit without fees.
• The ICC consumer site states the no-fee rule for that class.
• A larger account has only its own termination clause.
• Suppliers must be ICC-certified.
• Agents, brokers and consultants must also be certified.

What to establish before comparing an Illinois offer

The Illinois-specific questions are the ones about which side of a line the account sits on. Confirm which utility delivers the site and whether it is one of the three choice territories or a municipal or co-op system with none. Establish whether the account is inside the small commercial class — at or below 15,000 kilowatt-hours a year for aggregation purposes — or above it, because that decides both the aggregation pool and the no-fee exit. Pull the Price to Compare at the account's own usage and season, then make the supplier state whether the offer covers transmission as well as supply and how it treats the purchased-electricity adjustment. Confirm the delivery class from the meter's demand history, especially in Ameren territory where a drift across the 150 kW or 1,000 kW line changes the tariff. Finally, since the last twelve months of interval data is what both a utility class and a supplier price are built from, gather it before asking anyone for a number. Competitive supply depends on the service address, the meter and the utility territory, and not every address has a choice. An inquiry places no order and switches no supplier, and HighGround may receive compensation from providers on completed purchases.

• Confirm the delivery utility and whether choice exists there.
• Establish whether the account is small commercial or above the line.
• Pull the Price to Compare at your own usage and season.
• Make the supplier state its transmission and PEA treatment.
• Check the delivery class against the meter's demand history.
• Gather twelve months of usage data before asking for pricing.
• An inquiry places no order and switches no supplier.

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