Natural Gas Guides for Illinois Businesses

Natural gas choice looks like electricity choice on the surface — an eligible business can buy the gas commodity competitively while the utility delivers it — but the rules differ by territory, and in one large territory the model is entirely different. The gas utility depends on location: Peoples Gas serves the City of Chicago, Nicor Gas serves most of northern Illinois outside Chicago, North Shore Gas serves parts of Lake County and the far-north suburbs, and Ameren Illinois serves much of downstate. Some communities sit on a boundary, so the utility name on a recent bill is the reliable confirmation.

In Nicor, Peoples, and North Shore territory, eligible commercial customers can buy gas supply from a licensed alternative gas supplier through each utility’s Choices for You program while the utility continues delivery, metering, and emergency service. In Ameren Illinois gas territory, there is no standard small-commercial supplier-choice program; only larger non-residential customers can self-supply through Ameren’s Rider T transportation service. On this site we do not describe a “switch your gas supplier” path where it does not exist.

As with electricity, a gas bill splits into supply and delivery. The supply charge is the commodity, often priced per therm and, on utility service, tied to a periodically adjusted purchased-gas cost; delivery covers the utility’s pipes, metering, riders, and taxes and stays with the utility. A supplier contract prices the supply portion only, so applying a supply-price difference to the whole bill overstates any change.

Commercial gas load is usually heavily seasonal — winter-weighted for heating, though more constant for process or hot-water uses — which shapes how a term is priced and why a full year of therm usage matters for an accurate quote. That seasonality also makes the volume-tolerance terms important: a narrow swing band on a weather-sensitive building can turn an attractive headline price into an expensive one when a cold snap pushes usage outside the band. The shape of the year, not just the total, is part of what a supplier is pricing.

The honest comparison on the gas side is the same discipline used for electricity, adapted to the commodity. Rather than measuring a future fixed supplier price against a single historical utility purchased-gas-cost month — which mixes different periods and hides that future utility costs are unknown — a sound comparison uses the actual delivery period and treats budget certainty as a value separate from expected cost. And as with electricity, retail gas choice does not automatically save money; it is an option to evaluate for a specific account, in a specific territory, with the terms read.

Confirming the utility first is not a formality; it changes the entire path. A Chicago restaurant on Peoples Gas, a suburban warehouse on Nicor, and a Lake County plant on North Shore all have a standard commercial supplier-choice program available, while a downstate facility on Ameren does not — its only competitive route is Rider T transportation, and only if it is large enough to qualify. Advice written for one territory can be actively wrong in another, which is why the gas utility printed on a recent bill is the true starting point. A handful of communities sit on a boundary between utilities, so the bill settles it where a map cannot.

For accounts with meaningful gas load, the procurement discipline mirrors electricity but weights the seasonal and volume terms more heavily. Gather at least twelve months of therm usage so the winter-weighted shape is visible; identify the rate class and whether the account is a candidate for interruptible or transportation service; and compare offers on the actual delivery period rather than against a single utility purchased-gas-cost month. Larger facilities may find that transportation arrangements change the economics enough to be worth the added administration, while smaller accounts are usually best served by a straightforward fixed or structured supply comparison.

The through-line is that gas is its own decision, not an afterthought to electricity. For a hotel, restaurant, laundromat, or manufacturer, gas can be a comparable or larger share of the energy budget than power, and it renews on its own contract. Reviewing the two commodities together — and aligning their renewal dates where possible — lets a business look at its whole energy position once a year instead of reacting to two separate deadlines.

A safety note underlies all of this: whatever a business decides about gas supply, the delivery utility remains the emergency contact for a suspected leak or service problem. Choosing a competitive supplier does not change who to call or who responds; the utility still owns and maintains the pipes and the meter and handles emergencies. That separation between the commodity decision and the physical service is worth keeping clear, both for safety and for understanding what a supplier contract actually does.

These guides cover the territory map, how choice works, and procurement specifics for Chicagoland and downstate businesses — including where standard supplier choice applies and where, as in Ameren gas territory, only transportation service is available to qualifying larger accounts.