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Incentives/Policies for Renewables & Efficiency

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Interconnection Standards   

Last DSIRE Review: 10/10/2014
Program Overview:
State: Illinois
Incentive Type: Interconnection
Eligible Renewable/Other Technologies: Solar Thermal Electric, Photovoltaics, Landfill Gas, Wind, Biomass, Hydroelectric, Geothermal Electric, Fuel Cells, Municipal Solid Waste, CHP/Cogeneration, Anaerobic Digestion, Tidal Energy, Wave Energy, Ocean Thermal, Fuel Cells using Renewable Fuels, Microturbines, Other Distributed Generation Technologies
Applicable Sectors: Commercial, Industrial, Residential, Nonprofit, Schools, Local Government, State Government, Fed. Government, Agricultural, Institutional
Applicable Utilities:Investor-owned utilities
System Capacity Limit:No limit specified
Standard Agreement:Yes
Insurance Requirements:Vary by system size and/or type; levels established by PSC
External Disconnect Switch:Required
Net Metering Required:No
Authority 1:
Date Enacted:
Date Effective:
ยง 220 ILCS 5/16-107.5
Authority 2:
Date Enacted:
Date Effective:
83 Ill. Adm. Code, Part 466
Authority 3:
Date Enacted:
Date Effective:
83 Ill. Adm. Code, Part 467

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.

  Eric Schlaf
Illinois Commerce Commission
527 East Capitol
P.O. Box 19280
Springfield, IL 62794-9280
Phone: (217) 782-2743
Fax: (217) 782-1042
Web Site:
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Disclaimer: The information presented on the DSIRE web site provides an unofficial overview of financial incentives and other policies. It does not constitute professional tax advice or other professional financial guidance, and it should not be used as the only source of information when making purchasing decisions, investment decisions or tax decisions, or when executing other binding agreements. Please refer to the individual contact provided below each summary to verify that a specific financial incentive or other policy applies to your project.

While the DSIRE staff strives to provide the best information possible, the DSIRE staff, the N.C. Solar Center, N.C. State University and the Interstate Renewable Energy Council, Inc. make no representations or warranties, either express or implied, concerning the accuracy, completeness, reliability or suitability of the information. The DSIRE staff, the N.C. Solar Center, N.C. State University and the Interstate Renewable Energy Council, Inc. disclaim all liability of any kind arising out of your use or misuse of the information contained or referenced on DSIRE Web pages.

Copyright 2014 - 2015 North Carolina State University, under NREL Subcontract No. XEU-0-99515-01. Permission granted only for personal or educational use, or for use by or on behalf of the U.S. government. North Carolina State University prohibits the unauthorized display, reproduction, sale, and/or distribution of all or portions of the content of the Database of State Incentives for Renewables and Efficiency (DSIRE) without prior, written consent.