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Illinois: Trace a change from filing to the affected account
Start with FERC: interstate and intrastate pipeline responsibilities. The table below links this decision to the represented gas companies in Illinois. It does not establish service or supplier availability for every account.
Keep a tariff change record
Record issuing utility, docket or filing reference, affected schedule, approval status, effective date and the first service period affected. Compare the approved sheet with the account’s actual classification.
Treat branding and enrollment separately
A company acquisition or a renamed program does not by itself establish a new price, automatic contract cancellation or eligibility at another utility. Retain customer notices and confirm the legal company and effective service rules.
Illinois utility application
| Gas service company | Schedule and implementation evidence | Primary reference |
|---|---|---|
| Nicor Gas | The named delivery company and its eligible small-commercial service class | Official program / tariff |
| Ameren Illinois | Ameren gas rate zone, service class and any separately qualified transportation schedule | Official program / tariff |
| Peoples Gas | The named delivery company and its eligible small-commercial service class | Official program / tariff |
| North Shore Gas | The named delivery company and its eligible small-commercial service class | Official program / tariff |
| MidAmerican Energy | Operating state and MidAmerican commercial gas rate | Official program / tariff |
Nicor Gas: the program detail behind this decision
The ICC identifies Nicor Gas, Peoples Gas and North Shore Gas for residential and small-commercial Gas Choice. An Alternative Gas Supplier sells supply while the delivery utility remains. The ICC’s utility list does not establish that every supplier accepts every commercial class or offers a suitable contract. Program Illinois.
Apply the evidence to an account file
Match a proposed or approved change to The named delivery company and its eligible small-commercial service class. Reopen the effective company reference and confirm Supplier registration, cancellation terms and return-to-utility conditions instead of importing a rule from another service company.
A change log with an explicit implementation gate
Use a row for the company, source URL, document type, schedule, status, approval date, effective date, affected accounts and action owner. A proposed sheet can inform a sensitivity scenario while remaining outside the effective budget. After approval, verify the final sheet rather than assuming the requested amount survived. For an ownership change, attach the service notice and identify any separate legacy rate areas. Retain the prior reference for earlier billing periods so corrections can be checked against the right rules.
Turn the review into a calculation
Plan notice and enrollment milestones. The planner uses your calendar-day inputs and does not send notices or confirm a utility enrollment date.
Read the Illinois utility guide for the wider service-company distinctions. Convert billed gas units using the bill’s heat-content factor when moving from volume to energy.
Sources and review notes
- FERC: interstate and intrastate pipeline responsibilities
- Illinois ICC Natural Gas Choice FAQ
- Midamerican Territory
Reviewed October 16, 2026. Program information can change. Confirm the effective utility tariff, supplier availability and written offer before proceeding. Examples and planning tools are educational; they are not executable quotes or verified customer results.