Public Service Commission pauses rule changes on what counts as a transmission-line “modification”

The Public Service Commission on Sept. 12 heard staff recommendations to revise how the commission defines a “modification” to existing transmission lines under its certificate-of-public-convenience-and-necessity (CPCN) rules and then took the matter under advisement.

Michael Dean, speaking for commission staff, summarized staff’s submission and proposed edits to the rulemaking record in Rulemaking 91. Dean said staff filed proposed changes after the commission’s notice of Sept. 12, 2025, and in response to order number 890684. He described staff’s primary edits as combining the definition of modification for generating stations into the definition for transmission-line modifications, reordering subsections, removing a proposed reference to operating-voltage changes, and proposing a set of enumerated exemptions for certain routine or like-for-like work.

Those proposed exemptions, as recounted by staff, include: rebuilding all or part of an existing transmission line consistent with an approved CPCN application; replacement of a transmission structure with certain limits on height where the replacement does not exceed adjacent structures or where any height increase is necessary to meet industry or utility design standards; replacement with a higher or larger structure when required by current standards or when the increase in height or size does not exceed 25 percent; increases to the size of a structure’s base or foundation; adding new transmission structures within or adjacent to an existing right-of-way to facilitate interconnection provided height limits or design-standards justifications are met; use of a larger replacement conductor to increase capacity if the conductor diameter increase does not exceed 25 percent and the line voltage is not increased; routine maintenance or repairs; and replacement or upgrade of shield wires. Dean said staff’s proposal generally tracked a filing by the Joint Exelon Utilities of Sept. 4, 2025, but staff did not accept a proposed categorical 25 percent height increase in all circumstances.

Commission discussion did not produce a formal vote. Chair Hoover of the Public Service Commission said the commission would take the written proposals and comments under advisement and issue a written order explaining next steps. Chair Hoover said the order will give directions to staff and explain the commission’s view of its current authority and whether any legislative changes might be necessary.

During a brief appearance, Daniel Herson, representing the Joint Exelon Utilities, asked whether parties would have an opportunity to comment on any written issuance. "I just wanted to make sure that, if the commission is issuing something, would the parties have an opportunity to comment?" Herson asked. Chair Hoover replied, "Yeah. Yeah. We will. Yeah."

The record from the session shows staff’s changes remain proposals; the commission did not adopt final rule language at this meeting. Commissioners indicated they will issue a written order that outlines staff directions and requests responses from parties before any final action or codified change is adopted.

The commission’s discussion focused on statutory and technical definitions in the CPCN rule set and on the practical effect of a percent-based threshold (25%) for when structural or conductor size changes would trigger a requirement to obtain or amend a CPCN. No formal rule adoption or vote was recorded at the Sept. 12 session.