Commonwealth Edison Company Submits Transmission Interconnection Agreement with Ameren Illinois Company

Strategic Insights -

Commonwealth Edison Company (ComEd), an Illinois-based electricity supplier, has submitted a Transmission Interconnection Agreement (TIA) to the Federal Energy Regulatory Commission (FERC) for review and acceptance. The TIA, which replaces the existing agreement accepted by FERC in 2015, outlines the terms and conditions for the interconnected operation of ComEd's and Ameren Illinois Company's (AIC) respective transmission systems. The agreement has been designated as Service Agreement No. 4212 under the PJM Tariff and is effective as of July 22, 2025.

The TIA has undergone significant changes, including updates to the title page, introductory paragraph, recitals, and various articles to reflect changes to interconnection points, metering, and dispute resolution processes. The agreement also includes new provisions governing MISO and PJM's roles and the parties' authority to enter into the TIA. ComEd has requested that the Commission grant an effective date of July 22, 2025, for the TIA, which is sixty-one days after the date of this filing.

Key Takeaways:

  • The Transmission Interconnection Agreement (TIA) submitted by ComEd to FERC replaces the existing agreement accepted in 2015 and outlines the terms and conditions for the interconnected operation of ComEd's and Ameren Illinois Company's (AIC) respective transmission systems.
  • The TIA includes significant changes, including updates to the title page, introductory paragraph, recitals, and various articles to reflect changes to interconnection points, metering, and dispute resolution processes.
  • The agreement has been designated as Service Agreement No. 4212 under the PJM Tariff and is effective as of July 22, 2025.
  • ComEd has requested that the Commission grant an effective date of July 22, 2025, for the TIA, which is sixty-one days after the date of this filing.
  • The TIA includes new provisions governing MISO and PJM's roles and the parties' authority to enter into the TIA.
  • ComEd has submitted a marked comparison of the public and non-public versions of the TIA against the public and non-public versions of the 2015 Agreement, respectively.
  • The TIA has been reviewed by MISO, which has authorized the Parties to state that it has reviewed the revised TIA and intends to file a Certificate of Concurrence.

Statistics:

  • 73,000 miles of overhead and underground transmission and distribution facilities maintained by ComEd in northern Illinois and Northern Indiana.
  • Over 4 million customers served by ComEd.
  • 61 days: The requested effective date for the TIA, which is sixty-one days after the date of this filing.
  • 2015: The year in which the existing TIA was accepted by FERC.
  • 2015 Agreement: The agreement being replaced by the new TIA submitted by ComEd.
  • 2025: The year in which the TIA is effective, as of July 22, 2025.

Sources:

  • Commonwealth Edison Company, "Transmission Interconnection Agreement with Ameren Illinois Company" (Submitted to Federal Energy Regulatory Commission, May 22, 2025).
  • Order No. 714 (Federal Energy Regulatory Commission, 2024).
  • 18 C.F.R. SSSS 35.13 (2024).
  • https://www.ferc.gov/ceii (Commission's procedures for access to CEII materials).
  • https://www.pjm.com/library/filing-order (PJM's internet site with FERC filings).
  • http://www.ferc.gov/docs-filing/elibrary.asp (Commission's eLibrary website).