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Combined Heat and Power Partnership

Illinois Interconnection Standards

Date Last Updated8/12/2014
Policy TypeInterconnection Standard
State/FederalIL
Policy Administrator/Contact OfficeIllinois Commerce Commission (ICC), Office of Governmental Affairs
Policy Initiation Date8/29/2008
Policy SummaryICC established standard interconnection connection requirements for distributed generation systems, including CHP. For distributed generation systems up to 10 MW, the 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:
  • Tier 1: applies to certified, inverter-based systems up to 10 kW. The Tier 1 agreement is a simplified version of that used for projects requiring higher levels of review.
  • Tier 2: applies to certified systems up to 2 MW, connected to a radial distribution network or a spot network serving one customer.
  • Tier 3: applies to certified systems up to 50 kW, connected to an area network and from which power will not be exported, or certified, non-exporting systems up to 10 MW, connected to a radial distribution network.
  • Tier 4: applies to systems up to 10 MW 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 and 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. Facilities >1 MW must carry liability insurance with coverage of at least $2 million per occurrence and $4 million in aggregate. All systems are required to have an external disconnect switch directly accessible to the utility. The rules also specify a procedure for dispute resolution.

For DG systems (including CHP) >10 MW, an interconnection feasibility study and a system impact study will be required. A standard interconnection agreement form is available from the utility, and fees and insurance requirements will be determined on a case-by-case basis.
CHP Eligibility RequirementsBoth fossil-fueled and renewably-fueled CHP systems are eligible for standardized interconnection.
Eligible Project Size (MW)Standardized interconnection applies to systems up to 10 MW.
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