Interconnection Standards (Illinois)

From Open Energy Information

Last modified on February 12, 2015.

Rules Regulations Policies Program

Place Illinois
Name Interconnection Standards
Incentive Type Interconnection
Applicable Sector Agricultural, Commercial, Fed. Government, Industrial, Institutional, Local Government, Nonprofit, Residential, Schools, State Government
Eligible Technologies Anaerobic Digestion, Biomass, CHP/Cogeneration, Fuel Cells, Fuel Cells using Renewable Fuels, Geothermal Electric, Hydroelectric, Landfill Gas, Microturbines, Municipal Solid Waste, Ocean Thermal, Other Distributed Generation Technologies, Photovoltaics, Solar Thermal Electric, Tidal Energy, Wave Energy, Wind
Active Incentive Yes
Implementing Sector State/Territory
Energy Category Renewable Energy Incentive Programs
Applicable Utilities Investor-owned utilities

External Disconnect Switch Required

Insurance Requirements Vary by system size and/or type; levels established by PSC

Net Metering Required No

Standard Agreement Yes
System Capacity Limit No limit specified

Date added to DSIRE 2008-03-28
Last DSIRE Review 2012-11-28

References DSIRE[1]


In August 2007, Illinois enacted legislation (S.B. 680) requiring the Illinois Commerce Commission (ICC) to establish standards for net metering and interconnection for renewable energy systems by April 1, 2008. Although S.B. 680 only requires the promulgation of interconnection standards for "eligible renewable generating equipment," the ICC chose to take this opportunity to develop standards for all distributed generation up to 10 megawatts (MW). Final interconnection standards were adopted by the ICC in August 2008. In March 2010, the ICC established interconnection standards for Large Distributed Generation Facilities, or those over 10 MW.

Interconnection of Distributed Generation Facilities (up to 10 MW)

The interconnection rules set four levels of review for interconnection requests. A project must meet all of the requirements of a given classification in order to be eligible for that level of expedited review. The level of review required is generally based on system capacity, whether system components are certified by a nationally recognized testing laboratory (NRTL), and whether the system is connected to a radial distribution circuit or to an area network. The basic definitions* for each tier are as follows:

  • Tier 1: Certified, inverter-based systems with a capacity rating of 10 kilowatts (kW) or less.
  • Tier 2: Certified systems with a capacity rating of 2 MW or less, connected to a radial distribution network or a spot network serving one customer.
  • Tier 3: Certified systems with a capacity rating of 50 kW or less connected to an area network and from which power will not be exported; or certified, non-power-exporting systems with a capacity rating of 10 MW or less connected to a radial distribution network.
  • Tier 4: Systems with a capacity of 10 MW or less that do not meet the criteria for inclusion in a lower tier, including all systems using non-certified components and those that require additional construction by the utility in order accommodate the facility.

The ICC adopted IEEE 1547 as the technical standard of evaluation in July 2007. Systems are considered to be lab-certified if the components have been evaluated as compliant with UL 1741 and the 2008 National Electric Code (NEC) according to the testing protocols of IEEE 1547. The rules also specify the technical screens which may be applied to applications at each level of review as well as time limits for different stages of the evaluation process. Generally speaking, higher level applications are subject to more intensive screening and longer time limits.

All systems are required to have an external disconnect switch directly accessible to the utility. Facilities larger than 1 MW must carry liability insurance with coverage of at least $2 million per occurrence and $4 million in aggregate. Standardized interconnection agreements are available for all four tiers. The Tier 1 agreement is a simplified version of that used for projects requiring higher levels of review.

Interconnection of Large Distributed Generation Facilities (10 MW or larger)

The ICC adopted a separate set of rules applicable to distributed generation facilities over 10 Megawatts, which are not covered under the above interconnection standards. These rules provide a standard set of procedures covering the interconnection process as well as standard agreements. It should be noted that interconnections covered by the Federal Energy Regulatory Commission (FERC), the Midwest Independent Transmission System Operator, or PJM Interconnection are not subject to these new rules. See ICC Docket 08-0481 for more information.

* The definitions here cover several important classification criteria; however, interested parties should consult the actual rule for more precise definitions and additional restrictions.

Incentive Contact

Contact Name Eric Schlaf
Department Illinois Commerce Commission
Address 527 East Capitol
Address 2 P.O. Box 19280
Place Springfield, Illinois
Zip/Postal Code 62794-9280
Phone (217) 782-2743


Authorities (Please contact the if there are any file problems.)

Authority 1: § 220 ILCS 5/16-107.5
Date Effective 2007-08-24
Date Enacted 2007-08-24

Authority 2: 83 Ill. Adm. Code, Part 466
Date Effective 2008-08-25
Date Enacted 2008-08-13

Authority 3: 83 Ill. Adm. Code, Part 467
Date Effective 2010-03-01
Date Enacted 2010-02-10

  • Incentive and policy data are reviewed and approved by the N.C. Solar Center's DSIRE project staff.[1]


  1. 1.0 1.1  "Database of State Incentives for Renewables and Efficiency (DSIRE)"