Rules by state

Solar and battery interconnection rules in Illinois

Illinois electric interconnection of distributed generation. Every threshold below was read out of the document linked at the bottom of this page, and the same rules answer the free screening check.

Who this binds: investor owned utilities. A utility outside that list sets its own terms, so confirm who serves the address first.

Check a Illinois address free
How the size is measured

nameplate capacity: the maximum rated output in kilovolt-amps of a generator, prime mover, energy storage system or other electric power production equipment. Export capacity is the nameplate capacity in kilovolt-amps except where limited by an acceptable means. Illinois measures in kilovolt-amps rather than kilowatts.

Size bands and what each one obliges

Level 1 Size 0 to 25 kW

An export capacity of 25 kW or less and a nameplate capacity of 50 kW or less. Both tests must pass. The screen places this tier at 25 kW because a system with no stated export limit exports everything it makes; a deliberately export limited design may reach the higher nameplate allowance. The application fee is $50. Illinois publishes no insurance requirement at any level.

  • $50 application fee
  • Export capacity not above 25 kW as well as nameplate not above 50 kW
  • No insurance published in the rule
Level 2 Size 25.001 to 5000 kW

Eligibility by line voltage, from 500 kW below 5 kV up to 5 MW at 30 to 69 kV. Facilities connecting above 69 kV are ineligible regardless of size. The fee is $100 plus $1.00 per kVA.

  • $100 plus $1.00 per kVA
  • Supplemental review paid at the utility good faith estimate if required
Level 3 Size 5000.001 to 10000 kW

Area network facilities of 50 kW or less, and radial facilities where aggregate export capacity on the circuit is 10 MVA or less. The fee is $500 plus $2.00 per kVA.

  • $500 plus $2.00 per kVA

The screens that decide it

Ask the utility this, before you sell it

  1. Did this customer register for net metering before 1 January 2025? If so the old retail rate service continues for the lifetime of the system, and it survives both a change of electricity provider and a change of the customer benefiting from it. If not, the credit is one for one on supply charges only.
  2. If the project includes storage, confirm the tariff has been modified to net meter it. The 104th General Assembly required each electricity provider to modify its tariffs within 30 days to allow net metering for an energy storage or vehicle storage system of not more than 5,000 kilowatts nameplate.
  3. What is the relevant minimum load on this line section? Illinois screens against minimum load rather than peak load and only the utility holds the figure.
  4. Is this address served by a municipal utility or a cooperative? Neither is Commission jurisdictional and Part 466 does not reach them.

Worth knowing before you quote

Illinois publishes no insurance requirement at any level, confirmed by reading the general requirements section and the fee appendix rather than inferred. Level 4 covers everything that fails the lower levels at $1,000 plus $2.00 per kVA, applied toward any subsequent studies. Part 466 has a dedicated limited export and non exporting section, and storage sits inside the nameplate capacity definition. On compensation the statute is precise and it matters more than the interconnection fee: on and after 1 January 2025 the old net metering service is no longer offered to new customers. A facility registered before that date keeps it for the lifetime of the system, and that entitlement survives both a change of electricity provider and a change of the customer benefiting from the system, which makes an existing array a real asset on a resale. A customer starting after that date receives a one for one kilowatt hour or monetary credit against supply charges only, meaning the energy, capacity, transmission and purchased energy adjustment components, chosen by the customer at the time of application and not changeable later. Delivery charges are not offset. The statute sizes an eligible facility qualitatively, as intended primarily to offset the customer own current or future electrical requirements, with future requirements defined to include modeled use on occupying a new or vacant property, so there is no percentage test. The 104th General Assembly also required every electricity provider to modify its tariffs to net meter an energy storage or vehicle storage system of not more than 5,000 kilowatts nameplate.

Utility programs we have read in Illinois

Source

Illinois Administrative Code Title 83 Part 466, electric interconnection of distributed generation facilities, with net metering at Part 465

Read and recorded 2026-09-12. Binds electric distribution companies, defined as electric utilities subject to Commerce Commission jurisdiction. Municipals and cooperatives are not Commission jurisdictional and are outside it. Retail rate net metering closed to new customers on 31 December 2024 for Commonwealth Edison and Ameren Illinois and on 1 January 2025 for MidAmerican; new customers take hourly net billing.

What to do with this

Check a real address

The rules below are the general case. Run the free check to see which utility serves a specific address, which tier the system lands in, and what to ask.

Run the free check
Installers: keep the answer with the job

GridProjeX holds the project from here, with every value tied to the document it came from and the utility and permit tracks run to permission to operate.

How it works for installers
Utilities: see what applicants are told

The same published rules your applicants read here are the ones your queue sees. GridProjeX is the record both sides work from.

How it works for utilities

Also from CivyxIQ, if they fit what you already do: SolarProjeX for running the crews and the jobs, and Solar Home so the homeowner can follow their own project. Neither is needed to use the checker.